Draft Report Submitted: 3 October 2013

Lead Seahorse Expert:
Dr. Amanda Vincent a.vincent@fisheries.ubc.ca
Project Seahorse
Fisheries Centre
The University of British Columbia
2202 Main Mall
Vancouver, BC V6T 1Z4
Phone: 604-827-5475
Fax: 604-827-5199
Web: www.projectseahorse.org
Research Associate:
Dr. Sarah Foster s.foster@fisheries.ubc.ca
Seahorse Biologist:
Lindsay Aylesworth l.aylesworth@fisheries.ubc.ca

LIST OF FIGURES ............................................................................................................................... iv
LIST OF TABLES .................................................................................................................................. v
EXECUTIVE SUMMARY ..................................................................................................................... vi
PREFACE ......................................................................................................................................... vii
PROJECT BACKGROUND .................................................................................................................... 1
PHASE 1: SEAHORSE REVIEW REPORT: BIOLOGY AND ECOLOGY OF SEAHORSES ................................. 5
1.1. KEY POINTS FROM OUR PHASE 1 REVIEW: ............................................................................................5
1.2. SEAHORSE TAXONOMY........................................................................................................................7
1.2.1. Seahorse taxonomy in general ...............................................................................................................7
1.2.2. Taxonomy of H. kuda ..............................................................................................................................8
1.2.3. Confirmation of species found at Lung Mei Project Site and Ting Kok East Relocation Site ..................8
1.3. SEAHORSE DISTRIBUTION ................................................................................................................. 10
1.3.1. Distribution of H. kuda in Hong Kong SAR ........................................................................................... 11
1.3.2. Distribution of H. kuda globally ........................................................................................................... 11
1.3.3. Distribution of other Hippocampus spp. in Hong Kong SAR ................................................................ 12
1.3.4. Distribution of Hippocampus spp. in Southeast Asia ........................................................................... 12
1.4. ABUNDANCE .................................................................................................................................... 12
1.5. SEAHORSE SURVIVAL ........................................................................................................................ 12
1.5.1. Survival of H. kuda (see 1.9.6 on Ecology: Predation) ......................................................................... 13
1.5.2. Survival of other Hippocampus spp. .................................................................................................... 13
1.6. SEAHORSE GROWTH ......................................................................................................................... 13
1.6.1. Growth of H. kuda ................................................................................................................................ 14
1.6.2. Growth of other Hippocampus spp. .................................................................................................... 14
1.7. SEAHORSE REPRODUCTION & BREEDING BEHAVIOUR ...................................................................... 14
1.7.1. Reproduction in H. kuda ...................................................................................................................... 14
1.7.2. Reproduction in other Hippocampus spp. ........................................................................................... 16
1.8. SEAHORSE MOVEMENT & DISPERSAL ................................................................................................ 16
1.8.1. Movement and dispersal of H. kuda .................................................................................................... 16
1.8.2. Movement and dispersal of other Hippocampus spp.......................................................................... 17
1.9. ECOLOGY .......................................................................................................................................... 18
1.9.1. Abiotic habitat requirements of H. kuda ............................................................................................. 19
1.9.2. Abiotic habitat requirements for other Hippocampus spp. ................................................................. 19
1.9.3. Responses to habitat change – H. kuda ............................................................................................... 19
1.9.4. Responses to habitat change – other syngnathids .............................................................................. 20
1.9.5. Artificial habitat ................................................................................................................................... 21
1.9.6. Hippocampus kuda as predator ........................................................................................................... 21
1.9.7. Other syngnathids as predators ........................................................................................................... 22
1.9.8. Seahorses as prey ................................................................................................................................ 22
1.10. THREATS & CONSERVATION ............................................................................................................ 22
1.10.1. Threats to H. Kuda worldwide ........................................................................................................... 23
1.10.2. Threats to Hippocampus spp worldwide ........................................................................................... 23
1.10.3. Seahorse conservation in Hong Kong SAR ......................................................................................... 24
1.11. PHASE 1 SUMMARY ........................................................................................................................ 24 iii

PHASE 2: SEAHORSE INVESTIGATION REPORT – CHARACTERIZING THE HABITAT AND SEAHORSES AT
LUNG MEI AND TING KOK EAST ....................................................................................................... 26
2.1. ERM’S APPROACH IN CHOOSING TING KOK EAST AS THE RELOCATION SITE ....................................... 27
2.1.1. Tolo Harbour marine and coastal ecosystem ...................................................................................... 27
2.1.2. Characterizing the Lung Mei Project Site ............................................................................................. 28
2.1.3. Characterizing and selecting the Reference Sites and Relocation Site ................................................ 32
2.1.4. Habitat comparison between Lung Mei and Ting Kok East ................................................................. 35
2.2. CHARACTERIZING SEAHORSES AT LUNG MEI PROJECT SITE AND TING KOK EAST RELOCATION SITE ..... 36
2.3. PHASE 2 SUMMARY .......................................................................................................................... 40
PHASE 3: PRECAUTIONARY MITIGATION REPORT ........................................................................... 41
3.1. INTRODUCTION ................................................................................................................................ 41
3.2. POSSIBLE IMPACTS OF THE PROJECT ................................................................................................. 41
3.2.1. Possible impacts on seahorses at the Lung Mei Project Site, assuming no relocation ....................... 42
3.2.2. Possible impacts on Seahorses in Ting Kok East Relocation Site ......................................................... 45
3.2.3. Possible impacts on seahorses elsewhere in Greater Lung Mei .......................................................... 45
3.2.4. Additions to ERM’s Precautionary Mitigation Measures Report ......................................................... 46
3.3. POSSIBLE IMPACTS OF THE REMEDIATION / RELOCATION PLAN ......................................................... 48
3.3.1. Possible impacts of relocation on seahorses from the Lung Mei Project Site ..................................... 48
3.3.2. Possible impacts of relocation on seahorses in the Ting Kok East Relocation Site ............................. 48
3.3.3. Possible impacts of relocation on seahorses elsewhere in Greater Lung Mei .................................... 49
3.3.4. Additions to ERM’s Precautionary Mitigation Measures Report on relocation activities of seahorses from Lung Mei Project Site to Ting Kok East Relocation Site ......................................................................... 49
3.4. ENHANCEMENTS FOR ERM’S PROPOSED PRECAUTIONARY MITIGATION MEASURES ........................... 50
3.4.1. Setting the goal and objectives for mitigation process ....................................................................... 50
3.4.2. Target seahorse species ....................................................................................................................... 51
3.4.3. Monitoring before relocation in Lung Mei Project Site and Ting Kok East Relocation Site ................. 51
3.4.4. Capture and measurement methods ................................................................................................... 52
3.4.5. Tagging the seahorses .......................................................................................................................... 53
3.4.6. Search and capture methods for eventual relocation ......................................................................... 53
3.4.7. Transport to relocation site ................................................................................................................. 54
3.4.8. Release at Ting Kok East Relocation Site ............................................................................................. 55
3.4.9. Monitoring after relocation ................................................................................................................. 55
3.4.10. Special considerations for seahorses in sensitive conditions ............................................................ 56
3.4.11. Identifying signs of seahorse stress ................................................................................................... 56
3.5. CONCLUSION FOR PHASE 3 ................................................................................................................ 56
APPENDICES .................................................................................................................................... 58
APPENDIX 1 – Seahorse species found in Southeast Asia ........................................................................... 58
APPENDIX 2 - Sygnathid growth rate estimates ........................................................................................ 61
APPENDIX 3 – Sample monitoring sheets for seahorse surveys .................................................................. 62
REFERENCES .................................................................................................................................... 64
iv

F
IGURE
1.
M
AP OF
L
UNG
M
EI IN
P
LOVER
C
OVE IN
T
AI
P
O
, H
ONG
K
ONG
SAR,
INDICATING
L
UNG
M
EI
P ROJECT S ITE AND G REATER L UNG M EI . ............................................................................................. 1
F IGURE 2.
M AP OF T ING K OK E AST IN P LOVER C OVE IN T AI P O , H ONG K ONG SAR, INDICATING T ING K OK
E
AST
R
ELOCATION
S
ITE
. ...................................................................................................................... 2
F IGURE 3.
H IPPOCAMPUS KUDA .. .................................................................................................................. 3
F IGURE 4.
A ) H IPPOCAMPUS KUDA , B ) H.
SPINOSISSIMUS AND C ) H.
TRIMACULATUS . ..................................... 9
F
IGURE
5.
L
OCATION OF
L
UNG
M
EI AND
12 R
EFERENCE
S
ITES
. ................................................................ 10
F IGURE 6.
G LOBAL DISTRIBUTION OF H IPPOCAMPUS KUDA ....................................................................... 11
F IGURE 7.
D IAGRAM INDICATING THE DISTINGUISHING CHARACTERISTICS ............................................... 39
T ABLE 1.
R EPRODUCTIVE AND BREEDING CHARACTERISTICS OF H IPPOCAMPUS KUDA ............................... 15
T
ABLE
2.
P
OSSIBLE IMPACTS OF THE
P
ROJECT ON SEAHORSES AT THE
L
UNG
M
EI
P
ROJECT
S
ITE
, T
ING
K
OK
E AST R ELOCATION S ITE , AND G REATER L UNG M EI ........................................................................... 47
T ABLE 3.
P OSSIBLE IMPACTS OF MITIGATION ACTIVITIES ON SEAHORSES AT THE L UNG M EI P ROJECT S ITE ,
T
ING
K
OK
E
AST
R
ELOCATION
S
ITE AND
G
REATER
L
UNG
M
EI
.......................................................... 50
v

vi

Project Seahorse, the IUCN SSC Seahorse, Pipefish and Stickleback Specialist Group, was contracted by Hong Kong Civil Engineering and Development Department (CEDD) to review and provide expert input on the three reports produced by the consultancy firm, ERM. These reports covered an investigation to design precautionary mitigation measures for any seahorses found within a site targeted for Development of a Bathing Beach at Lung Mei, Tai Po, Hong Kong SAR. Project Seahorse is uniquely poised to comment on these ERM reports because of its unusual blend of expertise in seahorse research, management and policy.
Our report, entitled Independent Expert Review on Findings under Agreement No. PW 1/2013 is the output for that contract, and reviews/annotates/comments (etc.) on the three reports produced by ERM.
Following the ERM format, our report is broken down into three phases, providing comments, critiques and supplemental information where relevant.
PHASE 1: SEAHORSE REVIEW REPORT: BIOLOGY AND ECOLOGY OF
SEAHORSES – In this first section of our report to Hong Kong CEDD, we comment on the literature review in ERM’s Phase 1
Seahorse Review Report .
PHASE 2: SEAHORSE INVESTIGATION REPORT – CHARACTERIZING THE
HABITAT AND SEAHORSES AT LUNG MEI AND TING KOK EAST – In this second section of our report to the Hong Kong CEDD we review ERM’s Phase 2
Seahorse
Investigation Report , and provide comments and revisions.
PHASE 3: PRECAUTIONARY MITIGATION REPORT – In this third (and final) section of our report we summarize the potential impacts of the Project on seahorses, with special reference to ERM’s Phase 3
Precautionary Mitigation Measures Report .
Project Seahorse activities were executed by the following staff:
Amanda Vincent, PhD: Director, Project Seahorse and Chair, IUCN SSC Seahorse, Pipefish and
Stickleback Specialist Group.
Sarah Foster, PhD: Programme Manager, Project Seahorse and Member, IUCN SSC Seahorse,
Pipefish and Stickleback Specialist Group.
Lindsay Aylesworth, BSc: Seahorse Biologist, Project Seahorse.
Scott Finestone, BSc: Operations Manager, Project Seahorse. vii

Lung Mei, located in Plover Cove in Tai Po, Hong Kong SAR (
Figure 1
), is adjacent to a prominent
leisure area, Tai Mei Tuk, which provides well-established facilities and water-based recreation activities for holiday-makers[1]. In 1998, the ex-Provincial Regional Council of Hong Kong SAR recommended development of a pubic bathing beach (the Project) at Lung Mei (Lung Mei Project Site or Project Site) because of the inadequate capacity of the public swimming pool in the district[1]. After the completion of a feasibility study in 2001 and an environmental impact assessment (EIA) in 2008, an environmental permit was awarded for the construction of the Project in April 2010[1].
Figure 1. Map of Lung Mei in Plover Cove in Tai Po, Hong Kong SAR, indicating Lung Mei Project Site and Greater Lung Mei.
Also indicated are intertidal and subtidal (dive) seahorse survey areas, and location of seahorse sightings, as described in ERM’s
Seahorse Investigation Report (2013).
The conditions of the environmental permit for the Project included requirements to implement precautionary measures to minimize potential adverse impacts on fish species of conservation importance found at Lung Mei Project Site[1]. All studies carried out through 2011 found only three fishes of conservation importance at the Project Site: the two-spot goby ( Psammogobius biocellataus ); the tropical sand goby ( Favonigobius reichei) ; and the grass puffer ( Takifugu niphobles )[2-5]. The EIA reports concluded that there would be no unacceptable residual marine ecological impacts from the
1

Project on these species[3]. Despite of the findings of the EIA and additional surveys, public concern remained high about the potential Project impacts on the marine environment[1]. In response, the Civil
Engineering and Development Department (CEDD) commissioned an additional study in 2012 that recommended the relocation of echinoderms and the three fish species of conservation importance from the intertidal area of the Lung Mei Project Site to the intertidal area of Ting Kok East, also in Plover
Cove (hereafter referred to as the ‘Relocation Site’; Figure 2 )[1].
Figure 2. Map of Ting Kok East in Plover Cove in Tai Po, Hong Kong SAR, indicating Ting Kok East Relocation Site. Also indicated are intertidal and subtidal (dive) seahorse survey areas, and location of seahorse sightings, as described in ERM’s
Seahorse Investigation Report (2013).
At the same time that the relocation was recommended, members of the public raised concerns about potential impacts of the Project on other fishes of conservation concern, the seahorses ( Hippocampus spp.)[1]. Although the EIA (surveys in 2006) and EIA Supplementary Surveys (surveys in 2008) had found no seahorses in the Lung Mei Project Site, environmental groups and individuals noted that there had been previous sightings of spotted seahorses ( Hippocampus kuda
, Figure 3 ) at the Project Site[1]. In
consideration of the public concern, and the Vulnerable status of H. kuda on the IUCN Red List of
Threatened Species, the Hong Kong Civil Engineering and Development Department (CEDD) contracted the consultancy firm ERM to carry out an investigation and to design precautionary mitigation measures for any seahorses found within the proposed Lung Mei Project Site[1]. ERM undertook its work in three phases:
2

Phase 1: To review the relevant biological and ecological literature on seahorses as it relates to those that may be found in the Project Site. ERM reports on this objective in their document named the Seahorse Review Report [6].
Phase 2: To provide baseline information on the characteristics of seahorses and their habitats at the Project Site and Ting Kok East Relocation Site. ERM reports on this objective in their document named the Seahorse Investigation Report [7].
Phase 3: To design and propose precautionary mitigation measures for seahorses that may be found at the Project Site, including those in sensitive conditions (e.g. pregnant, ready to breed, injured), and provide guidelines for post-procedure monitoring of those seahorses.
ERM reports on this objective in their document named the Precautionary Mitigation
Measures Report [8].
Figure 3. Hippocampus kuda . Photo by Photo by N. Samaras.
Project Seahorse (which acts as the IUCN SSC Seahorse, Pipefish and Stickleback Specialist Group) has now been contracted by Hong Kong CEDD to provide expert input on the three reports produced by
ERM. Project Seahorse, a group based at the University of British Columbia (Canada) and Zoological
Society of London (UK), is uniquely poised to provide such advice, given its unusual blend of research,
3

management and policy expertise. Project Seahorse is the recognised global authority on seahorse biology, trade, and fisheries management, as measured by its diverse seahorse-expertise roles, including:
(i) IUCN SSC Specialist Group for Seahorses, Pipefishes and Sticklebacks; (ii) Chair, CITES Working
Group on syngnathids; (iii) FishBase Authority for syngnathids, (iv) authors of papers and definitive taxonomy.
This report, entitled Independent Expert Review on Findings under Agreement No. PW 1/2013 is the output for that contract, and reviews each of the three reports produced by ERM. Following the
ERM format, our report is broken down into three phases, providing comments, critiques and supplemental information where relevant. The report on each phase begins with is a summary of key messages arising from our review of the Project and the work done by ERM.
4

In this first section of our report to Hong Kong CEDD, we comment on the literature review in the
Seahorse Review Report provided by ERM Consulting. In so doing we have:
-
Confirmed the taxonomy of the seahorses found during the course of ERM’s investigation.
-
Supplemented the literature review of seahorse biology and ecology, with particular focus on reproduction, and movement and dispersal.
-
Collated and scanned biological knowledge of seahorse species in the Hong Kong SAR, with particular reference to H. kuda .
-
Drawn on the biology of other seahorse species to infer life history and population parameters for H. kuda where species-specific estimates were lacking.
Seahorses have life history characteristics that make their populations susceptible to fishing and coastal development including low fecundity, low mobility, mate fidelity and parental care, and they typically are found vulnerable marine habitats[9]. However seahorses have other characteristics, such as a generalist diet, which helps offset these risks [9]. Understanding the biological characteristics of H. kuda will enable us to evaluate the potential impacts of the Project and proposed mitigation measures on these species and their susceptibility or resilience to these impacts.
1.1. KEY POINTS FROM OUR PHASE 1 REVIEW:
Taxonomy: We confirm the taxonomy of the seahorses sighted at Lung Mei Project Site and Ting Kok
East Relocation Site as H. kuda . We also note that other species may be present in the Tolo Harbour region, especially H. spinosissimus and H. trimaculatus . We provide identification characteristics for these species in case that they are sighted in future survey work.
Distribution: We explain surveys of longer duration and broader spatial coverage are needed for Tolo
Harbour, in order to determine how seahorse distributions vary over space and time. Understanding temporal shifts in species distributions is critical to determining impacts and mitigation for the Project but we do not yet know whether the seahorses’ geographic distributions, habitats, or depths change over the course of a year. Nor we do not know whether species other than H. kuda may be present in Lung
Mei Project Site, Greater Lung Mei or Ting Kok East at different times of year.
Abundance: Our extensive literature review revealed no published information on the abundance or natural densities of wild H. kuda anywhere in its geographic range, including Hong Kong SAR.
Survival: Survival rates or life spans for wild H. kuda remain unknown. In captivity, H. kuda specimens have been reported to live to two years, and survival of all life stages has been shown to vary with temperature and salinity. It is unclear to what extent any of this remains true for wild populations.
Growth: Species with faster growth rates are generally more resilient to anthropogenic impacts than species that grow slowly. Growth rates in seahorses have been poorly investigated to date, especially for
5

wild populations, but limited information on captive H. kuda suggested they grow rapidly at rates that are comparable to those of other syngnathids.
Reproduction: We have updated the summary of H. kuda reproductive and breeding characteristics provided by ERM. Available information indicates that H. kuda mature at larger sizes and older ages than other seahorse species of similar size, reproduce year-round but with seasonal peaks, have highly variable brood sizes and are monogamous.
Movement and dispersal: The limited available information on H. kuda movement and dispersal suggests they maintain home ranges but little is known about how these vary in size among life stages and habitats. Although there is evidence that long distance dispersal via rafting on floating materials was likely an important factor in the spread of H. kuda across Southeast Asia, mechanisms for dispersal of different life stages on shorter time scales remain unknown. Nor do we understand seasonal movement patterns.
Ecology: Most of our discussion of habitat requirements for H. kuda is limited to abiotic factors because the ERM report has already detailed the key biotic factors. Important abiotic habitat variables include temperature, salinity and pH. Questions about H. kuda habitat that arise from our review of other seahorses include habitat partitioning by life stage and seasons, and the species response to changes in habitat quantity and quality (such as water pollution, noise pollution, etc.). We also do not know the extent to which anthropogenic habitats may influence H. kuda distribution and density.
Threats: Hong Kong SAR is the largest global consumer of dried seahorses for traditional Chinese medicine, but most of these fish come from outside Hong Kong’s waters, such as off the coast of
Thailand. The greatest threat to local seahorses in Hong Kong SAR is from coastal development and associated habitat degradation. There is no known target fishery for seahorses in Hong Kong SAR, and bycatch is no longer a problem because of the implementation of a trawl ban in Hong Kong SAR waters.
Conservation: Hong Kong SAR has four marine parks and one marine reserve. These protect habitats that could be home to seahorses - including coral reefs, mangroves and seagrass beds – but we do not know if seahorses are actually found in these areas. The trawl ban certainly should afford seahorses in
Hong Kong SAR some protection, given that trawling is commonly a major threat to seahorse populations.
6

Based on our thorough review of seahorse biology and ecology, a few key gaps remain in our understanding of seahorses in the Lung Mei Project Site and Ting Kok East Relocation Site. These limit our ability to assess the potential impacts from the Project and proposed mitigation plans.

Spatial and temporal trends in distribution and abundance of H. kuda and other species (especially
H. trimaculatus ), including seasonal movement patterns; home range size and variations by habitat type.
 Mating and reproduction patterns of H. kuda and other seahorse species in the Hong Kong region – including important habitats and seasons for mating and reproduction.
Habitat preferences of H. kuda in the wild, including habitat partitioning by life stage and seasons.

Impact of habitat changes such as water quality and noise pollution on H. kuda populations.

Response of H. kuda to artificial (anthropogenic) habitat changes in its natural environment (such as development).
1.2. SEAHORSE TAXONOMY
In its Phase 1 report Seahorse Review Report , ERM identified the seahorses they found at Lung Mei
Project Site and Ting Kok East Relocation Site as H. kuda , without explanation. Unfortunately, seahorses can be very difficult to identify with many species looking very much alike. The name H. kuda, in particular, has been assigned to a variety of species[10]. In this section, we therefore supplement ERM’s Phase 1 report with a general discussion of seahorse taxonomy and the challenges it poses, and by confirming and justifying the taxonomy of the seahorses found by ERM.
1.2.1. Seahorse taxonomy in general
Globally, the taxonomy of seahorses still requires clarification and creates many species identification challenges[11]. The number of actual seahorse species is a point of conflict for scientists, with the relationships among the species not fully resolved[11]. Morphological, genetic and behavioural evidence suggests there are currently about 48 species[12], once synonyms have been reconciled. This differs from the number reported by ERM (55 species), which may have relied on alternative classification schemes[13, 14]. It turns out that many scientists claiming a new species are, in fact, simply renaming one that has already been described[11]. Some species do, however, have distinguishing features that allow for easier identification[10].
Names given to seahorses are often unreliable[11]. This is partly because seahorses specialize in crypsis, can change colour and grow skin filaments to match their surroundings[11] and are morphologically similar to other species[10]. That said, some species (e.g. H. abdominalis and H. trimaculatus )[10] are quite distinctive. We do not know how seahorse appearance is affected by habitat, geographic location, temperature, and/or age[11].
7

1.2.2. Taxonomy of H. kuda
The name H. kuda is taxonomically problematic because it has been used for virtually any smooth seahorse from the Indo-Pacific basin[10]. Taxonomic work has suggested that at least 15 names for apparently distinct species were merely synonyms for H. kuda [10]. Three additional Southeast Asian seahorse species ( H. barbouri, H. comes, and H. kelloggi) were once part of the H. kuda complex[10].
For the smooth seahorses found throughout Southeast Asia, H. kelloggi and H. kuda can be particularly difficult to tell apart because of their morphological similarity and individual seahorses that vary in morphology and are non-descript[10]. Untangling this species complex wherein a single name is applied to many species is difficult, and a final resolution will only emerge after more detailed analysis[10].
Additional taxonomic and genetic information is needed to clarify the relationships in the H. kuda complex[10] – and it is critical that such justification be given when assigning this name to seahorse specimens.
1.2.3. Confirmation of species found at Lung Mei Project Site and Ting Kok East Relocation Site
Our report will focus on H. kuda as the only seahorse species positively identified in the area. After reviewing the photographs provided by ERM, Project Seahorse confirms that the 12 seahorses found at the Lung Mei Project Site and Ting Kok East Relocation Site are H. kuda, based on the following characteristics among others: a) smooth body with no spines; b) coronet turned back with rounded and
broad flanges; and c) a deep body[10] (
Figure 4
).
8

Figure 4. a) Hippocampus kuda , b) H. spinosissimus and c) H. trimaculatus .
All drawings by Lawrence Richardson, and extracted from [10].
9

The identification of ERM’s seahorse specimens as
H. kuda is compatible with findings from previous studies in the Tolo Harbour marine ecosystem. The Agriculture Fisheries and Conservation Department of Hong Kong SAR (AFCD) carried out field surveys during December 2012 and January 2013 at Lung
Mei, Ting Kok East, Yung Shue O North and Lai Chi Chong (see
Figure 5
), where it also reported
sightings of H. kuda [15] (we discuss these surveys in more detail in 2.1.2.4). Additionally, a separate study reported adult H. kuda at Kei Ling Hai Lo Wai[16], which is adjacent to Yung Shue O North in
Three Fathoms Cove (
Figure 5
).
Figure 5. Location of Lung Mei and 12 Reference Sites.
1.3. SEAHORSE DISTRIBUTION
We here place the information on distribution of H. kuda provided by ERM within the broader context of all Hippocampus species found in Hong Kong SAR region and Southeast Asia. Such information is central to evaluating impacts of the proposed Project on seahorses. We really do need to understand the distribution and occurrence of H.
kuda as well as other seahorse species that might be found in the
Project and Relocation Sites.
10

Our understanding of how seahorse distributions in Hong Kong vary over space and time should be enhanced with more survey effort. For example, the AFCD surveys undertaken in December 2012 and
January 2013 were only conducted for four days at Lung Mei Project Site and Ting Kok East Relocation
Site, and two days at Yung Shue O North and Lai Chi Chong[15] it is unclear what percentage of total available seahorse habitat was covered by these surveys.
1.3.1. Distribution of H. kuda in Hong Kong SAR
Hippocampus kuda is one of the most commonly reported seahorse species in Hong Kong SAR[15, 17].
Aside from its confirmed presence at the Project Site (see 1.2.3), annual reef check surveys conducted jointly by the AFCD and the Reef Check Foundation reported a total of 103 H. kuda sightings in waters off Yan Chau Tong, Hoi Ha Wan, Kat O, Sharp Island, Ninepin, Tung Ping Chau, Port Island and Bluff
Island from 2001 to 2012[15]. As stated by ERM, H. kuda has been primarily sighted in the eastern waters of Hong Kong SAR such as Hoi Ha Wan and Tai Mei Tuk within Tolo Harbour[6].
1.3.2. Distribution of H. kuda globally
Hippocampus kuda occur throughout both the eastern and western Indian Ocean as well as the central
and northwest regions of the Pacific Ocean[11] (
Figure 6
). The species is found in at least 20 national
and other jurisdictions [9] (Appendix 1).
Figure 6. Global distribution of Hippocampus kuda. Map from www.iSeahorse.org.
11

1.3.3. Distribution of other Hippocampus spp. in Hong Kong SAR
The only other seahorse species confirmed to occur in Hong Kong waters is H. trimaculatus [15, 17, 18], but no specific information on its distribution is available. A literature review of fish species known in
Hong Kong SAR waters describes the presence of H. trimaculatus from fisheries surveys, without their precise locations[18]. The Ocean Park Conservation Foundation of Hong Kong (OPCFHK) reported sighting H. trimaculatus during its 2010 surveys on the eastern side of Hong Kong SAR, but again without exact locations[17].
Based on known and suspected distributions, three other species may also occur in Hong Kong’s waters:
H. histrix, H. kelloggi , and H. spinosissimus [10]. OPCFHK reports that H. kelloggi is occurs in Hong
Kong’s waters, but provides no evidence for this claim[17]. Based on habitat preferences, it is reasonable to suspect that the H. spinosissimus and H. trimaculatus
( Figure 4 ) may be found in Lung
Mei, Ting Kok East and/or Plover Cove. Full identification features of these two species can be found at http://seahorse.fisheries.ubc.ca/why-seahorses/species .
1.3.4. Distribution of Hippocampus spp. in Southeast Asia
A total of 14 species of seahorses is found in Southeast Asia (Appendix 1). The largest, H. kelloggi , reaches heights of up to 28 cm (height in seahorses is measured as the distance from the top of the coronet to the tip of the straightened tail). The smallest species, H. satomiae , reaches only 1.1 cm in height as a fully-grown adult. Hippocampus histrix and H. kuda are confirmed from the largest number of countries throughout Southeast Asia. In contrast other species such as H. waleananus and H. pontohi are only found in a single nation’s waters.
1.4. ABUNDANCE
Seahorses are considered patchy and rare. The densities that have been reported (for 14/48 species) range from 0.001-0.51 seahorses m
-2
[19, 20]. Seahorses are generally found alone or in pairs[20], with seahorse partners are lingering in the same general vicinity[20, 21]. We found no published information on the abundance or natural densities of wild H. kuda . In Hong Kong SAR, OPCF’s first systematic seahorse survey covering 31 sites from September 2011 to October 2012 found only six H. kuda , indicating that their regional abundance is likely very low[17]. However survey effort per site was not reported[17]. Mean reported densities for a similarly sized estuarine seahorse species in the Caribbean,
H. reidi , ranged from 0.001 to 0.04 seahorses/m
2 [20]
.
1.5. SEAHORSE SURVIVAL
Understanding the factors that influence seahorse survival helps us to assess the potential impacts of the
Project as well as proposed mitigation measures. The lifespans and age-specific survival rates of seahorses, and the parameters that influence them, such as predation and disease, are virtually unknown for most species. Most estimates of maximum age and survival rates come from observations of
12

seahorses in captivity ( ex situ ) or from modeling exercises (e.g. cohort analysis), with uncertainties as to how estimates compare to actual lifespans of seahorses in the wild ( in situ ).
1.5.1. Survival of H.
kuda (see 1.9.6 on Ecology: Predation)
Hippocampus kuda individuals held in aquaria reputedly lived about two years[22]. However, some seahorses of similar-sized species live an average of 3 to 5 years in the wild (see 1.5.2). Male body size and pouch size have also been shown to influence the future fitness and survival of H. kuda offspring raised in captivity[23]. Ex situ research on H. kuda has identified disease caused by bacteria[24, 25], facultative parasites[26] and marine leeches[27].
1.5.2. Survival of other Hippocampus spp.
Inferred life spans for other seahorse species range from about 1 year in the very small species H. zosterae[28] to an average of 3 to 5 years for larger species ( H. capensis[29] ; H. guttulatus[30] ; H. hippocampus[31] ).
Natural mortality rates are unknown for almost all seahorse species. In Australia, about 86% of individually identified adult H. whitei that had been tagged were still present after four months[21]. In another study, however, H. comes was estimated to have a high rate of natural mortality[32]. Predation mortality is probably greatest in juveniles because their planktonic dispersal makes them susceptible to predation by piscivorous fish and planktivorous organisms[9]. Some individuals are also subject to partial predation by crabs (as indicated by direct observations of seahorses with shortened tails)[33, 34], juvenile fish[35], and shorebirds[35].
Reports of disease in Hippocampus have arisen from laboratory and aquaculture observations. Health ailments included those caused by bacteria[22, 24, 25], cestodes[36, 37] , microsporidians [37, 38] , fungi[39], ciliates[40, 41], trematodes[27, 42] and marine leeches[27].
1.6. SEAHORSE GROWTH
There are few data for seahorse growth rates in captivity and even fewer in the wild[9] . Yet i ndividual growth rates are key variables in determining how populations respond to natural and anthropogenic change; species with faster growth rates are generally more resilient to anthropogenic impacts than species that grow slowly[43]. Growth data can also be used to infer ages based on seahorse size, quantify reproduction and seasonal effects on reproduction, clarify natural and anthropogenic mortality, and compare these variables to those of other fishes in a management context[43].
Size or age at sexual maturity is also used to compare species growth rates – quicker growing species tend to mature at smaller sizes or younger ages[44]. Although the ERM report makes brief mention of rapid growth in seahorses, we now provide additional information about H. kuda and other seahorse species.
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1.6.1. Growth of H. kuda
Hippocampus kuda grows rapidly at rates that are comparable to those of other syngnathids; seahorses and pipefish from warm waters (Appendix 2). Reported maximum sizes of H. kuda vary from 15 cm[13] to 20.2 cm[45]. Estimates of size and age at sexual maturity for H. kuda are between 8 and 14 cm[46], and seven to eight months[47]. Ex situ studies of H. kuda reveal larval growth taking two to three weeks and high growth rates in the first few weeks following birth[48]. A rapid second growth stage, most likely influenced by the behavioural shift from pelagic to benthic form[48], occurs around 8 cm in length[48].
.
1.6.2. Growth of other Hippocampus spp.
Growth rates of a few other seahorse species have been studied in situ (Appendix 2). In one example, mathematical models were used to estimate differences in growth rates between males and females of H. whitei and also between groups of the same species living in two different habitats[49]. Results indicated minimal differences in growth rates between sexes, but different growth rates among seahorses living in different habitats[49].
1.7. SEAHORSE REPRODUCTION & BREEDING BEHAVIOUR
Of all seahorse characteristics, it is their breeding behaviour that makes them most vulnerable to anthropogenic impacts. In all seahorse species, the female transfers her eggs to the male, where they are fertilized [9]. The male then broods the developing embryos in a specialized abdominal pouch, providing them with nutrition, oxygen and a controlled environment [9]. After approximately 10 days to
6 weeks, depending on species and water temperature, the male gives birth to relatively few, independent young that disperse in the water column[9]. In many species, the same male and female mate repeatedly and exclusively[21].
1.7.1. Reproduction in H. kuda
In
Table 1
we have updated the summary of
H. kuda reproductive and breeding characteristics provided by ERM (Table 2.1 of their Seahorse Review Report , p. 7).
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Table 1. Reproductive and breeding characteristics of Hippocampus kuda
Characteristic
Breeding season
Average egg diameter
Gestation duration
Interval between pregnancies
Average length at birth
Minimum and maximum reported brood size
Minimum size at sexual maturity
Estimated age at sexual maturity
Pelagic duration of larvae
Mating pattern
Age at settlement
Sexual dimorphism
Description
12 months[50]
1.8 mm[51]
10-24 days[50, 52]
12 days[53]
7 mm[53]
30[52] - 1751[53]
101 mm in males[52], 110 mm in females[52]
7-12 months[54]
19-22 days[13]
Monogamous[55]
2-3 weeks[48]
None[54]
Age at maturity: Current, albeit limited, data indicates that H. kuda matures between seven and 12 months old[47, 54], whereas some other seahorse species can mature as early as 4-5 months[56] . Indeed in an ex situ study that compared H. kuda to two similarly sized tropical seahorse species, H. barbouri and H. fuscus , H. kuda was the slowest to mature and reproduce, but grew to be the longest and the largest[56].
Size at maturity: An ex situ study on H. kuda provides us with the most recent estimates of size at maturity for this species[52] . This study indicated that males matured younger than females, with males showing courtship signs like changes in colouration and posture at an average height of 101 ± 2 mm
(from 85-90 days old), whereas females matured at a slightly larger size of 110 ± 2 mm[52].
Breeding season: Reproduction is known to occur year-round in Viet Nam for H. kuda[50] . However reproductive peaks (peaks in number of pregnant males) have been observed in some parts of their range; e.g. in Viet Nam, peaks were observed in April, May, September and December[50].
Gestation length and egg diameter: Estimates for the gestation length of H. kuda comes from ex situ studies, and range from 10-24 days[50] to 21-24 days[52]. The difference in observed gestation lengths may be related to differences in ex situ water temperature[46] . Egg diameters measured from an ex situ study were 1.8 mm[51]. For ex situ animals, the time interval between pregnancies was recorded to be
12 days[53].
Brood sizes and newborn seahorses: The range in reported brood sizes for H. kuda is quite large, from
30[52] to 1751 young[53]. Newborn H. kuda average 7 mm in length[53] and spend an estimated 19-22 days as pelagic larvae[13]. Offspring of larger H. kuda parents have higher survival rates and higher postnatal growth rates than offspring of smaller parents[23]. Male body size, number of offspring, and pouch size are also known to influence the future fitness and survival of offspring[23].
Mating patterns and sexual dimorphism: Careful observations of mating revealed elaborate courtship occurs before mating in H. kuda as in many other seahorse species[57]. Hippocampus kuda is known to be monogamous within a breeding cycle, and does not demonstrate sexual dimorphism[54].
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1.7.2. Reproduction in other Hippocampus spp.
For the majority of seahorse species, information about age at sexual maturity has been obtained mostly from ex situ observations [9]. While size at maturity is a more useful indicator of maturity than age at maturity in seahorses[58], this information is missing for several heavily traded seahorse species.
Behavioural studies on seahorses confirmed that the majority of species exhibit monogamous pairing
[9]. Pair bonds are often reinforced by daily courtship greetings between partners. In H. whitei , the female seahorse initiated daily greetings[21]. Courtship began on the morning that the male had released his young, often enduring for up to 9 hours[21]. Despite the fact that male seahorses become pregnant, they still compete for mates at the beginning of the season[59]. However, this competitive behaviour is less common in low-density populations. In species where monogamous pair bonds were formed, daily courtship greetings were observed[60].
Monogamy in most species means that a widowed partner may stop reproducing, at least temporarily[21]. Low population densities mean that seahorses may have trouble finding a new partner[21]. Male brooding means that survival of the young in marsupio depends on the survival of the male[59]. Finally, their small brood size limits the potential reproductive rate of the pair (although this may be offset by frequent spawning and enhanced juvenile survival through parental care)[59].
1.8. SEAHORSE MOVEMENT & DISPERSAL
Since fish move to access the resources necessary for their survival, growth, and reproduction[61], movement is an important factor to take into consideration for evaluating the impacts of human activities such as the Project at Lung Mei and its mitigation. Sedentary animals, such as seahorses, tend to remain within a small area (i.e. home range) that allows them to access all vital resources including food, shelter/protection, and mating opportunities[61].
The key factors to review in a discussion of seahorse movement include adult home range, seasonal migrations, dispersal at different life stages, and dispersal through evolutionary time scales. We address each of these in turn for H. kuda and then fill in the gaps by examining information for other seahorses.
In so doing, we supplement information on seahorse movement and dispersal provided in the ERM report; most of that came from a single, short-term, displacement study.
1.8.1. Movement and dispersal of H. kuda
Home range: The only available study on H. kuda home range size showed that (as reported by ERM), adult H. kuda had overlapping home ranges with a mean area of 32.35 m
2
in a tropical eelgrass bed; no comment was made about changes in home range size with life history stages and/or habitat types[62] .
Juvenile dispersal: Juvenile dispersal by currents has been suggested for several species including H. kuda [51].
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Evolutionary dispersal: Movement and dispersal research to date on H. kuda has focused on the species’ historic dispersal across Southeast Asia[63]. Genetic evidence indicates that long distance dispersal via rafting on floating materials was likely an important factor in the spread of H. kuda across
Southeast Asia[63]. However, distant populations now appear to have developed a considerable degree of genetic isolation. Past research speculates that short shallow stretches of poor H. kuda habitat may be significant barriers dispersal[63]. This may be because habitats in deeper areas tend to show more geographic stability while shallow habitat can be ephemeral[63]. The probability of re-colonization of an area by H. kuda following a population loss was inferred to be low (at least within ecological timeframes) because of passive dispersal and inconsistent connectivity of high quality habitat[63].
1.8.2. Movement and dispersal of other Hippocampus spp.
Seahorse are sedentary, and move short distances on a daily basis, though there is recent evidence that they can move longer distances than previously thought[61]. The unusual body morphology of seahorses sacrifices speed in favour of high levels of maneuverability[61]. The caudal fin is absent from seahorses and their primary means of movement is achieved through undulation of the dorsal fin (amiiform swimming) which is poorly suited for forward propulsion [64]. When not swimming their grasping, prehensile tail allows them to securely anchor to holdfasts to stay in one location [64]. However, it is not uncommon for seahorses to be found lying on the seafloor not holding onto anything. Active movement over distance is limited by this body morphology. Instead, long distance dispersal may be achieved through more passive means. For example, adult seahorses have been found in the open ocean, hanging on to floating debris with their tails [65]. After birth, juvenile seahorses of some species spend several weeks in the water column before settling into small home ranges [66, 67].
Home ranges: The sedentary nature of seahorses during adulthood results in a home-range size that is often very small. Hippocampus comes, a tropical seahorse of similar size to H. kuda , was found to move just 5 m from their holdfast with individuals showing high fidelity to their chosen holdfast[68]. Paired seahorses had greater site fidelity than individuals lacking partners[68]. Only 15% of H. comes individuals observed over a 16 month study period moved away from their holdfast[68]. Mean relocation distance for H. comes was 11 m, with the longest relocation distance measuring 21.5 m.
Relocations often occurred as a result of a lost of holdfast or a missing partner[68]. In all cases, females tended to move greater distances than males[68].
Indeed most seahorse species studied to date have maintained individual home ranges, at least during the breeding season. For example, similar site fidelity patterns to H. kuda have been observed in H. reidi, H. subelongatus and H. whitei [21, 69]. Sex differences in home range size have been documented for some species such as H. guttulatus[70] , H. hippocampus[70] and H. reidi [69] Only one seahorse studied to date, H. abdominalis , which is a larger temperate species, does not exhibit high site fidelity
[49].
Unlike most other fish with limited home ranges[2, 71, 72], seahorses do not defend their territories[73].
The difference may reflect the fact that seahorses neither rely on oviposition sites or defend their young[73]. Presumably they do not find it necessary or energetically expedient to defend the area in which their partners or prey were found[73]. Such a situation might arise if partnerships were
17

maintained in some other manner and prey were either indefensible or abundant relative to size of the seahorse population[73].
One displacement study of H. guttulatus , resulted in very different movement patterns depending on whether they were placed near (<20 m) or far (>750 m) from their home ranges[61]. Individuals relocated to nearby locations moved only a short distance and showed evidence of homing ability, while individuals that were moved further traveled a much greater distance (up to 150 m) and did not demonstrate a homing ability[61]. This suggests that seahorses may have some homing ability to return to their previous locations, depending on how far they have been moved[61]. As summarized by ERM, individuals tended to move towards environments similar in both depth and water current speed to their original capture location[61]. However, the observations in this study were made over very short time periods (maximum of 10 days) and we do not know how the displaced seahorses behaved in the longer term[61].
The small home ranges of most seahorse species may have enabled the seahorses to adopt camouflage appropriate for their environment, and to maintain a stable social structure[73]. Seahorse movement patterns also have consequences for their resilience to anthropogenic impacts; low mobility and small home range sizes mean that seahorses may be slow to recolonize depleted areas (although this may be offset by planktonic dispersal of juveniles, discussed below)[61, 73].
Seasonal migrations: Adults of some species of seahorses may make seasonal migrations to deeper waters in the winter/colder months. Such moves have been inferred for H. erectus[74] , H. guttulatus[30] , H. hippocampus[30] , H. subelongatus[75] and H. whitei[21] , as well as for the pipefishes Syngnathus fuscus[76] and Syngnathus leptorhynchus[77] . It is unknown if H. kuda make seasonal migrations.
Dispersal at different life stages: Dispersal of seahorse adults over large distances appeared primarily to occur when adults were cast adrift by storms or carried away while grasping floating debris[63]. Adult
H. fisheri have been caught at the surface in the open sea[11], while the occurrence of H. ingens in the stomachs of tuna suggests they were occasionally found in the pelagic zone[78], possibly associated with rafts of drifting seaweed. Young seahorses are more likely to disperse than adults[9].
Some species are clearly planktonic immediately after birth whereas juveniles of other seahorse species have been inferred to be planktonic because they rose to the surface of the water column in captivity immediately after leaving the pouch, or did not settle immediately after birth in the wild[9]. The extent of juvenile dispersal by passive means is unknown but may explain some gene flow among populations; juvenile dispersal by currents has been suggested for several species including juvenile H. kuda[51] .
While in the water column, young seahorses may attach themselves to floating Sargassum weed and/or macroalgae[11].
1.9. ECOLOGY
Understanding the ecological characteristics of H. kuda will enable us to understand the potential for impacts from the Project and proposed mitigation activities on seahorses and their susceptibility or resilience to these impacts. Seahorses have ecological characteristics that make their populations
18

susceptible to fishing and coastal development. For example, seahorses often live in habitats such as estuaries, seagrass beds and coral reefs that are vulnerable to coastal development and pollution[9].
However seahorses have other characteristics, such as a generalist diet, which helps offset these risks[9].
Seahorses, like so many animal species, require different environmental conditions to survive, grow and reproduce; the latter usually requires the most specific and optimal conditions[9]. An appreciation of their ecological needs provides an important supplement to the ERM report. We focus on abiotic parameters because the ERM report has adequately detailed the key biotic factors.
1.9.1. Abiotic habitat requirements of H. kuda
As detailed above in 1.5.1 (Survival of H. kuda ), H. kuda are influenced by abiotic conditions including temperature, salinity and pH. Hippocampus kuda can tolerate temperatures ranging from 26-32°C but the optimal temperature range for fecundity and spawning is narrower, from 26 to 28°C[79]. The threshold for embryonic development was recorded at 13.7°C, below which temperatures are too cold for development[80]. Temperature has an indirect impact on the survival rates of newborn seahorses because of its effects on fecundity, spawning, fertilization and hatching of H. kuda [79, 80].
Hippocampus kuda has a high range of salinity tolerance ranging from 15 ppt to an upper limit of 50 ppt[81]. For juvenile H. kuda , the optimal salinity is about 15 to 20 ppt[81]. The best environment for H. kuda is one that is slightly alkaline, with pH of 7.4-8.5 [48, 52, 81, 82].
The photoperiod of H. kuda in aquaculture environment is often set around 12-hour light and 12-hour dark coinciding with reports that H. kuda is a diurnal species [48, 52, 81, 82].
1.9.2. Abiotic habitat requirements for other Hippocampus spp.
One consideration – to supplement the ERM report – is that seahorses may change habitat and depth choice as they grow[32, 69]. For example, H. comes prefer Sargassum spp. beds in shallow subtidal environments as juveniles, and then move to adjacent communities composed of hard corals and sponges when older[32]. Among adults, size classes may also differ in habitat occupancy, with larger individuals of some species found in deeper waters( H. comes [83]; H. reidi ,[69]).
Species habitat choice may also be linked to foraging strategy and prey use as demonstrated by the habitat differences between H. guttulatus and H. hippocampus , with the former a relatively sedentary ambush predator preferring complex habitat while the later an active forager for both planktonic and epibenthic prey prefers less complex habitats[19]. Additionally seahorses encountered on bare substrates
(including H. kuda ) may be temporarily exploiting open habitats while transitioning between covered microhabitats[19].
1.9.3. Responses to habitat change – H. kuda
Only one study has documented the response of H. kuda to changes in habitat. In Malaysia, H. kuda numbers declined as an extensive port development around the Pulai Estuary destroyed large tracts of a
19

seagrass meadow[84, 85]. This suggests that not only is H. kuda vulnerable to habitat loss, but also it may prefer more complex habitats.
1.9.4. Responses to habitat change – other syngnathids
Background information on seahorse responses to habitat change is vital to understanding potential impacts on relocation procedures and evaluating mitigation options. As there is little information on seahorse responses to change in their habitats, we here also draw on the relevant literature for their syngnathid relatives.
Syngnathids can certainly be affected (lethally or sublethally) by physical degradation and destruction of their habitats. In Florida populations of H. zosterae and Syngnathus scovelli in Tampa Bay declined during demolition and construction phases of two nearby marine projects that damaged seagrass habitats[86] . In the Philippines, coral reefs that had been degraded by blast and poison fishing had very low densities of H. comes [87]. Some species (e.g. S. fuscus ) also adjust foraging tactics to match varying habitat complexity[88], while variation in structural complexity had little effect on the foraging success of other species (e.g. H. erectus [89]).
At least some syngnathids may respond poorly to chemical pollutants, eutrophication or other changes in water quality and associated visibility. It is unclear whether seahorses have any particular sensitivity
(indicator species) to environmental change, but they are vulnerable to stress, which often manifests in disease[22]. Two Syngnathus species ( S. floridae and S. scovelli ) were significantly less abundant in polluted seagrass beds in the northeast Gulf of Mexico than in recovering ones[90]. Temporal trends in the mean annual population size of Nilsson’s pipefish
S. rostellatus , sampled from the Thames Estuary in the U.K., correlate with changes in water treatment practice and reductions in organic pollution[91] .
Some effects of reduced water quality arise from lower light levels or hypoxia associated with eutrophication or pollution. For example, lower light levels reduced prey capture rates by the seahorse
H. erectus[89] . This has broader implications as visual acuity has been recognized as important for prey capture in other syngnathids, e.g. S. typhle and S. abaster [92].
Hypoxic conditions arising from excessive fertilizer use in Chesapeake Bay, USA, led to reductions in feeding by northern and dusky pipefishes ( S. fuscus and S. floridae , respectively) that were predicted to affect health, growth and reproduction[93]. That said, both these pipefish species were able to tolerate low dissolved oxygen concentrations that were below levels lethal to most commercially important species [93]. Such tolerance accords with observations that seahorses are often found in habitats with highly variable water conditions (e.g. estuaries) and in places with suboptimal water quality (e.g. busy marinas[94]). Indeed, hypoxic conditions negatively affected embryonic growth but not embryonic survival in the brood pouch of a male S. typhle[95] .
Seahorses are vulnerable to noise pollution . Noise pollution may affect syngnathid populations, not least because their low mobility limits their ability to escape noisy areas. Seahorses exposed to loud noise in aquariums for 1 month demonstrated physiological, chronic stress responses with reduced mass and body condition[96] and spent less time stationary, an indication of irritation[97]. Reproductive and feeding rates had not, however, declined by the end of the experiment [96]. In the wild, settlement-stage
20

larval syngnathids certainly distinguish among noises, preferring high-frequency over low-frequency trap noise on coral reefs[98]. The implications of such distinctions have not, however, been assessed.
Habitat change may favour certain syngnathid populations, while challenging others.
For example, habitat damage caused by seine fishing in the Ria Formosa lagoon system, Portugal, benefited H. hippocampus over the sympatric H. guttulatus : the former prefers the simpler habitats that emerge from fishing while the latter occupied the more complex habitats that are damaged by seining[19]. Also, there were more S. scovelli in boat-scarred than in reference seagrass beds in Charlotte Harbor, Florida[99]. A vast increase in the numbers of pipefish Entelurus aequoreus in the north-east Atlantic Ocean and North
Sea after 2003 was variably attributed to (1) introduction of an alien habitat-forming seaweed
( Sargassum muticum ) that created habitat with more food and shelter for the pipefish, (2) increases in sea surface temperatures, (3) fishery removal of putative competitors and (4) expansions in the range of their prey items[22, 100-102]. That said, anecdotal reports suggest a considerable drop in numbers of E. aequoreus by 2010 [103].
1.9.5. Artificial habitat
Anthropogenic habitat has potential value for syngnathids to a level that needs to be investigated in the context of the Lung Mei installation of a shark net and relocation of some mooring buoys. Some seahorses are known to grasp artificial structures, and as reported by ERM in their Phase 1 report, H. kuda is one of them (fishnets and cages,[104]). Additionally, shark nets[105], salmon cages[106], wooden piers[107], jetty piles[108], and frayed net material[109] have all shown to act as seahorse habitat. Moreover, new research suggests that addition of artificial habitat may increase seahorse abundance in areas with degraded habitat[110].
The removal of artificial habitat has also had unforeseen consequences. In Tasmania, Australia, antipredator nets at Atlantic salmon farms can have large numbers of seahorses on them[111], which die when the nets are removed from the water to be treated against fouling[106]. Similarly, the numbers of
H. abdominalis and H. whitei declined significantly upon replacement of a swimming net in Australia, with recovery of the latter population taking >15 months[105]. The real conservation effect of removing nets will depend on whether they actually enhance seahorse numbers or merely act as fish attraction devices, spatially concentrating the same number of seahorses.
1.9.6. Hippocampus kuda as predator
Few studies have been conducted on H. kuda predator-prey relationships, except for several aquaculture related studies on growth-foraging patterns[79, 80]. Hippocampus kuda juveniles feed on zooplankton and the adults feed on crustaceans with a preference for mysids[80]. Newborn H. kuda had higher growth and survival rates when fed copepods compared to rotifers[53]. Hippocampus kuda adults were found to feed during the daytime with peaks in feeding rates at 12:00 and 18:00, they did not feed at night[113]. Seasonal food consumption in culture facilities has been observed to peak from May to
November[114]. These ex situ studies may provide some insight into H. kuda predatory habits in the wild.
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1.9.7. Other syngnathids as predators
Seahorses are generally considered ambush predators[89] and have many features, such as excellent camouflage, that facilitate prey capture[89, 112]. Ensuring adequate food supply is an important factor to consider when determining a relocation site for seahorses.
If we expand our review to include other seahorse species and their syngnathid relatives, we find that predatory behavior of seahorses can be influenced by habitat complexity . Hippocampus erectus obtains prey over a wide range of habitat complexities although they preferred to grasp a holdfast when feeding[89]. Among pipefish relatives, small size-classes of pipefish select prey based on their vulnerability to predation (i.e. attack smaller prey), while the prey preferences of large pipefish are influenced by habitat complexity[88]. As seahorses grow, their diet undergoes an ontogenetic shift from small to large food items[112, 115, 116].When seahorses are prolific, their feeding can affect the structure of some benthic invertebrate communities[117]. Seahorses show little intra-species competition, probably because of the relatively high abundance of their prey [115-117].
1.9.8. Seahorses as prey
As little is known about the predators of H. kuda , limited to records of them being eaten by trevally[35], we must reach to additional seahorse and syngnathid literature to gain an understanding of predators of seahorses. Seahorses are prey for many types of species, although their cryptic ability enables them to hide from most predators . When considering a site for relocation of seahorses, it is important to consider known predators to seahorses in the area.
Seahorses are generally eaten in low numbers. They have few natural predators because of their camouflage capabilities, and unpalatable bony plates and spines[47]. Several seagrass-dwelling species of seahorses, pipefish, and seadragons have developed filamentous appendages to mimic their surroundings[11]. Seahorses that live in corals often have a textured body surface to mimic the reef.
Though seahorses and other Syngnathidae are not an important part of any species’ diet, their primarily predators are teleost fishes (e.g. tuna, porgy)[35] and seabirds (e.g. terns, herons)[35]. Other predators include invertebrates (e.g. cuttlefish), elasmobranchs (e.g. sharks), reptiles (e.g. sea turtles), and mammals (e.g. dolphins)[35]. When seahorses become a larger component of diets, it is because they are foraged opportunistically during periods of high population densities; where seahorses are found in low numbers (as appears to be the case in the Hong Kong region, see 1.3.1) it is unlikely that they are an important part of the diet of other marine organisms[35].
Pipefishes and seahorses, when exposed to predation risk, may limit color-change displays normally used to attract mates[118]. Since pipefishes, seadragons and seahorses have limited swimming ability, they are vulnerable to more rapid-swimming predators if they are caught outside their normal habitat or their camouflage fails[35]. This may be one of the reasons to consider habitat when choosing a site for any relocation activity.
1.10. THREATS & CONSERVATION
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There are no known target fisheries for seahorses in Hong Kong SAR. Bycatch, which was a known pressure on seahorses historically, is no longer a problem due to the implementation of a trawl ban in
Hong Kong SAR waters[119]. Therefore the only threat to local seahorses in Hong Kong SAR is from coastal development and associated habitat degradation.
All seahorses are listed on Appendix II of the Convention on International Trade in Endangered Species
(CITES)[120]. Consequently, 178 nations are obliged to guarantee that their exports do not threaten wild seahorse populations. Hong Kong SAR requires an export permit from the source country for any shipment of seahorses into Hong Kong SAR, as mandated by CITES[119]. HK merchants should also report seahorse imports, although this is not a CITES obligation.
1.10.1. Threats to H. Kuda worldwide
Hippocampus kuda is listed as Vulnerable (VU A4cd) on the IUCN Red List of Threatened
Species[121]. This listing is based on inferred declines of at least 30% caused by targeted catch, incidental capture, and habitat degradation[121]. While there are few quantitative data on changes in population numbers of the species, there is indirect evidence to suggest that declines have taken place and are continuing[121].
Hippocampus kuda is caught and traded for traditional medicines, aquaria and curios throughout its range[122]. It is one of five species comprising the vast majority of international seahorse trade; trade in this species is extensive with hundreds of thousands of individuals exported per annum[94].
Hippocampus kuda is susceptible to incidental catch from trawling in many locations throughout its range[122, 123]. In China, Cambodia and the Republic of Korea seahorses are caught as bycatch although no information exists on volumes[124]. Declines in Thailand of seahorse catches are attributed to overfishing, an increasing number of fishers, activities of trawlers, and habitat destruction[122].
Hippocampus kuda is also threatened by damage to its habitats from coastal development and destructive fishing practices[125]. For example, in Malaysia, H. kuda numbers declined due to an extensive port development around the Pulai Estuary that destroyed large tracts of seagrass meadow[84,
85]. Land-based activities such as coastal construction can diminish seagrass beds and mangroves while leading to increased pollution and siltation in surrounding marine waters[126]. Some fishing methods such as trawling result in substantial damage to seagrass beds[126]. The decline in and fragmentation of the species’ habitats throughout its range raise the possibility of declines in populations in addition to those caused by fisheries.
1.10.2. Threats to Hippocampus spp worldwide
Many species of seahorse are now included in the IUCN Red List of Threatened Species[121], which serves to warn of serious concern, but does not itself impose any restrictions.
Seahorse species are
(variably) threatened by direct exploitation, accidental capture (bycatch), and habitat degradation[125] .
Some of the world’s poorest fishers make their living by targeting seahorses[125]. Bycatch from trawlers, however, appears to be the largest source of seahorses in international trade[33, 57, 122, 123,
127-129].
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Most exploited seahorses are exported either dried for traditional medicines, tonic foods, and curiosities, or live for ornamental display[125]. Traditional Chinese medicine and its derivatives account for the largest consumption of seahorses, with past estimates of the global trade exceeding 20 million dried seahorses annually[125]. However, capture for the live aquarium trade is the main pressure in certain regions [125].
Hong Kong SAR is one of the major global consumers of dry seahorses and at the global level, indeed a review of official trade data suggested that Hong Kong SAR was the largest consumer of dried seahorses globally[94]. High demand for seahorses as traditional Chinese medicine on the Hong Kong SAR markets contributes to the global threat to seahorse populations. The seahorses imported into Hong Kong SAR mainly come from Southeast Asian countries, including Thailand, but also from West African countries
Senegal and Guinea [94].
1.10.3. Seahorse conservation in Hong Kong SAR
Seahorses are not included on the Hong Kong SAR list of Key Species of Conservation Concern, nor are they protected by local law[119]. Hong Kong has four marine parks and one marine reserve to help protect habitats that may be home to seahorses, including coral reefs, mangroves and seagrass beds[119]. However no published systematic studies have been done to compare seahorse populations inside and outside these protected areas. Seahorses are certainly afforded some protection in Hong Kong
SAR by the trawl ban[119], as trawling is a major threat to seahorses where it occurs[125].
A full review of global seahorse conservation activity is available[125].
1.11. PHASE 1 SUMMARY
In this first section of our report to Hong Kong CEDD, we have commented and critiqued the literature review portion of the Seahorse Review Report provided by ERM Consulting in Phase 1 of its activities.
In so doing we have:
Confirmed the taxonomy of the seahorses found during the course of ERM’s investigation as H. kuda .
Supplemented the literature review of seahorse biology and ecology, with particular focus on reproduction, movement and dispersal.
Collated and scanned biological knowledge of seahorse species in the Hong Kong SAR, with particular reference to H. kuda .
Drawn on the biology of other syngnathid and seahorse species to infer life history and population parameters for H. kuda where species specific estimates were lacking.
Based on our thorough review of seahorse biology and ecology, a few key gaps remain in our understanding of seahorses in the Lung Mei Project Site and Ting Kok East Relocation Site. These limit our ability to assess the potential impacts from the Project and proposed mitigation plans.
24


Spatial and temporal trends in distribution and abundance of H. kuda and other species (especially
H. trimaculatus ), including seasonal movement patterns; home range size and variations by habitat type.
 Mating and reproduction patterns of H. kuda and other seahorse species in the Hong Kong region – including important habitats and seasons for mating and reproduction.
Habitat preferences of H. kuda in the wild, including habitat partitioning by life stage and seasons.

Impact of habitat changes such as water quality and noise pollution on H. kuda populations.

Response of H. kuda to artificial (anthropogenic) habitat changes in its natural environment (such as development).
With this information in mind, we turn to commenting on the seahorse survey investigation undertaken by ERM to characterize seahorse populations in Lung Mei Project Site and Ting Kok East Relocation
Site. In the next section of our report, we will examine the information ERM was able to provide on seahorses at the two locations in Phase 2 of their project activities.
25

There have been conflicting reports about the presence of seahorses at the Lung Mei Project Site.
Neither the EIA surveys nor supplemental surveys found any seahorses, including the spotted seahorse
H. kuda . However, environmental groups and individuals have reported sightings of spotted seahorses at the Project Site. In consideration of the public concern, and the ‘Vulnerable’ status of the spotted seahorses on the IUCN Red List of Threatened Species[121], the Hong Kong CEDD contracted the consultancy firm ERM to investigate the presence of seahorses at the Lung Mei Project Site and identified Ting Kok East Relocation Site [7].
In this second section of our report to the Hong Kong CEDD we review ERM’s Seahorse Investigation
Report[7] , and provide comments and revisions. Our review has two main objectives:
 2.1. To evaluate ERM’s approach in deciding upon Ting Kok East as the Relocation Site for species of conservation concern being moved from Lung Mei Project Site.

2.2. To evaluate how ERM found and characterized the seahorses at both the Lung Mei
Project Site and the Ting Kok East Relocation Site.
With meeting objective 2.1, we have reviewed and commented on:

Tolo Harbour marine and costal ecosystem;
 characterization of habitat in the Lung Mei Project Site,;
 characterization of habitat in five Reference Sites (those that were evaluated for their suitability as relocation sites, including Ting Kok East, Shuen Wan, Wu Chau, Yung Shue O
North and Lai Chi Chong;
Figure 5
);
 characterization of habitat in the three potential relocation sites (the Reference Sites that were considered as candidate relocation sites, including Ting Kok East, Yung Shue O North, Lai
Chi Chong); and
 criteria by which ERM chose the designated Relocation Site as Ting Kok East.
In meeting objective 2.2 we have reviewed and commented on:
 methods employed by ERM to find and characterize the seahorses in the Project and
Relocation Sites; and
 results from ERM’s seahorse surveys in the Project and Relocation Sites.
We will address the proposed plan of mitigation, monitoring and evaluation in Phase 3 of our report.
26

2.1. ERM’S APPROACH IN CHOOSING TING KOK EAST AS THE RELOCATION SITE
In this section of our report we evaluate the steps taken by ERM to identify Ting Kok East as the
Relocation Site for seahorses from Lung Mei Project Site. ERM had previously chosen Ting Kok East as the site for receiving the echinoderms and three fish species of conservation concern from Lung Mei before seahorses were known to be at the Lung Mei Project Site.
Two important pieces of information are missing from ERM’s Phase 1 Seahorse Review Report[6] and
Phase 2 Seahorse Investigation Report[7] . First, ERM does not explain how it characterized the ecological profile of the Project Site (Lung Mei) or the Relocation site (Ting Kok East). Second, it does not describe the entire process by which it chose Ting Kok East as the Relocation Site. We address these gaps in order to ensure the process is transparent to a third party observer, and to analyze whether Ting
Kok East is indeed a suitable Relocation Site for H. kuda . This required us to consult and summarize information contained in the EIA[3], Supplemental EIA[4], Further Marine Ecology Investigation[5] and AFCD Surveys[15].
We take four approaches in evaluating the suitability of Ting Kok East as a Relocation Site:
1.
We collate available information on Tolo Harbour ecosystem in which Lung Mei Project Site and Ting Kok East are situated (2.1.1).
2.
We review the surveys conducted by ERM in 2006, 2008 and 2012, and AFCD in 2012/2013 to infer what might be missing in an ecological characteristics of Lung Mei Project Site (2.1.2).
3.
We evaluate the steps taken by ERM to choose Ting Kok East as the Relocation Site for animals, including seahorses, from Lung Mei Project Site (2.1.3).
4.
We compare the ecological characteristics of the two sites, Lung Mei Project Site and Ting Kok
East Relocation Site, to evaluate their similarity (2.1.4).
We conclude that the characterization of the biological and ecological profiles of Lung Mei Project Site and Ting Kok East Relocation Site were adequate, and we confirm the similarity of the two sites. There was, however, an apparent lack of consideration for abiotic factors in these two areas.
We here modify and enhance the good approaches that ERM used to identify suitable relocation sites for the seahorses from Lung Mei Project Site.
Proximity to the Project Site may be an important factor in making such a decision, but we suggest other important factors to consider when evaluating relocation sites.
2.1.1. Tolo Harbour marine and coastal ecosystem
The Project Site and the five Reference Sites (those that were considered candidate relocations sites; see
2.1.3.1 below)
are all located in the Tolo Harbour marine coastal ecosystem (
Figure 5
)[130] .
Understanding the general characteristics of Tolo Harbour is, therefore, important in evaluating the conditions needed by local species, the connectivity among all sites, and general threats to the ecosystem. As this broader context is missing from ERM reports to CEDD, we consulted the published literature to provide it here for due consideration.
The characteristics of Tolo Harbour have led to historic problems of pollution and degradation from human activities[130, 131]. The Tolo Harbour marine coastal ecosystem is located in the north-eastern
27

part of Hong Kong (
Figure 5
)[130]. Tolo Harbour is nearly land-locked, with only one narrow channel
connecting it to the open sea[130]. Tolo Harbour is approximately 15 km in length, and the average depth varies from less than 10 m in the Harbour subzone and subtidal areas to over 20 m in the Channel near the mouth[130]. The tidal currents are very slow both at the Harbour (0.04 ms
-1
) and in the Channel
(0.08 ms
-1
), leading to weak water circulation[130]. Additionally, the prevailing northeasterly winds throughout the year entrap pollutants in Tolo Harbour[130, 131].
The Tolo Harbour marine ecosystem and coastal zone have degraded since the 1970’s because of urbanization, industrialization and livestock rearing[130, 131]. Additionally, Hong Kong’s largest reservoir (in terms of area) was constructed in the 1960’s, with ensuing sea filling[130, 131]. These threats have degraded water quality by increasing freshwater run-off, pollutants, and turbidity[130, 131].
As a result, the overall abundance and diversity of marine communities have decreased throughout the ecosystem (including phytoplankton, fish, intertidal and subtidal benthos)[130, 131]. Although water quality improved throughout the 1990’s as a result of the Tolo Harbour Action Plan, hypoxia remains a chronic problem in some parts of the ecosystem[130].
2.1.2. Characterizing the Lung Mei Project Site
In this section of our report we review and synthesize background information that was used by ERM to characterize the ecological profile of the Lung Mei Project Site. This was necessary because ERM’s literature review provided no biological information on the habitat and species in the Site[6].
2.1.2.1. ERM’s EIA for Development of Bathing Beach at Lung Mei, Tai Po
An environmental impact assessment (EIA) was carried out by ERM in 2006 in support of an environmental permit application for the construction of the bathing beach at Lung Mei. This report contained a literature review on intertidal and benthic assemblages within Lung Mei, and little information was available. Consequently baseline surveys on intertidal, benthic and subtidal habitats were undertaken to characterize the Project Site. Coral and mangrove habitats were additionally surveyed as were areas located within 500 m from the proposed Project Site, including Ting Kok Special
Site of Scientific Interest (Ting Kok SSSI), East Yeung Chau and North Mai Shi Chau ( Figure 5 ).
A variety of different methods were used to characterize the habitats of Lung Mei Project Site and the surrounding areas. Qualitative surveys were carried out along the shore and in mangroves to describe the diversity of macrofauna and mangrove species. Belt transects were carried out along the artificial / disturbed shoreline perpendicular to the waterline to assess distribution and abundance (density) of flora; five quadrats were placed randomly along each transect, and all animals in each quadrat were identified to the species level. For areas on the vertical seawall, qualitative surveys were undertaken to produce a complete species list. Benthic surveys included core sampling to provide an indication of the quality of the sediment and volumes of different types of sediment to be dredged. Subtidal dive surveys allowed for semi-quantitative information of subtidal habitat to be obtained, including information on seabed composition, presence / absence of hard and soft corals and their relative abundance. These dive surveys were carried out at Tai Mei Tuk, Yeung Chau and Ma Shi Chau, and each consisted of 5x10 m transects
28

running parallel to shoreline. After each transect was laid out video footage was taken to allow for assessment of benthic cover and taxon abundance. Each transect was approximately 4 m wide.
These surveys provided a thorough snapshot of the ecological characteristics of Lung Mei and surround areas in 2006, but the limited temporal replication means we cannot know how these characteristics might vary across seasons or across years . Surveys were carried out for only three days in three consecutive months (one day in each of October, November and December 2006). Furthermore, the surveys were undertaken seven years ago, and it is possible that the ecological profile of the area has changed since then.
2.1.2.2. Further Information submitted by ERM under section 8.(1) of the Environmental Impact
Assessment Ordinance (EIAO) Technical Memorandum
After review of the EIA document the Hong Kong Environmental Protection Department requested additional ecological surveys. ERM conducted Supplemental EIA surveys of Lung Mei (and Reference
Sites, see 2.1.3.1) in both the dry and wet seasons of 2008. These intertidal surveys (that included the shallow subtidal) focused on the diversity, rarity, abundance and richness of wildlife. Two types of surveys were carried out:
Active searching was conducted during the night in the dry season and day in the wet season to account for extreme spring low tides which occur at these opposing times. Direct observations were made in all major habitat and substrate types. Hand netting was employed to collect highly mobile organisms, i.e. shrimp, crab, and fish. Surveys involved 4-7 specialists, each spending 2-3 hours at a site, subject to the site and tidal conditions. The effort spent searching at each site was standardized to “number of man hours” spent searching to facilitate comparison of results among sites. These active were used to produce an extensive list of marine fauna at surveyed sites.
Quantitative surveys included intertidal transects to quantify habitat, benthic cores, and crustacean and fish surveys to examine the diversity and abundance of intertidal and shallow subtidal fauna at Lung Mei
Project Site. These active searches were undertaken at Lung Mei Project Site during low tide, once in the dry season (March 2008) and once in the wet season (May 2008).
For the intertidal surveys, 3x30 m horizontal transects were haphazardly deployed parallel to the shoreline at each of three shore heights – 0.5 m, 1 m and 1.5 m – which intertidal fauna typically inhabit.
Five 25x25 cm quadrats were placed randomly along each transect to assess the abundance and diversity of marine fauna. Surface sediment was wet-sieved to obtain all mobile organisms living on or in the surface sediment within each quadrat (“epifauna”). All crustacean species observed and their relative abundance along each transect was recorded.
Benthic sediment core samples were collected from the three shore heights – 0.5 m, 1 m and 1.5 m – with seven core samples taken randomly at each height. Two of these samples were analyzed for particle size distribution and the remaining five samples were used to examine the diversity and abundance of infauna.
29

The intertidal fish surveys involved field observation, photographic record and drop-trapping during day-time low tide to examine diversity and abundance of fish species in the study area. Drop traps are essentially bottomless boxes that are dropped onto the sediment surface to enclose a known area, and are suitable for repetitive sampling of small fishes and /or highly mobile marine organisms such as shrimp and crabs in shallow water.
Several statistical tests were conducted to evaluate the similarity of the fauna found at Lung Mei Project
Site and Ting Kok East Relocation Site. Shannon-Weiner Diversity Index and Pielou’s Evenness Test were used to compare epifaunal assemblages in terms of diversity and abundance of species. ANOVA tests were performed to determine whether species richness and abundance differed between the sites, among years and among seasons. Community differences between sites were tested using the Plymouth
Routines in Multivariate Ecological Research (PRIMERv6) software. Analysis of similarity (ANOSIM) was conducted to test the null hypothesis that there were no differences between sites and between seasons. A similarity of percent analysis (SIMPER) was used to identify the discriminating taxa between sites and between seasons.
As was the case with the EIA surveys of 2006, the snapshot picture provided by ERM’s extensive survey methods was thorough and complete, but lacked temporal replication. Surveys were undertaken only once in dry season and once in wet season. Additionally, these surveys were carried out five years ago, and species composition and abundance may have changed since then.
2.1.2.3. Further Investigation and Design of Marine Ecological Mitigation Measures March 2012
ERM’s 2012 surveys aimed to update past information on both the Project Site and the Relocation Site
(Ting Kok East), to assess the biological similarities of these sites, and to confirm the choice of
Relocation Site. These surveys included the intertidal areas within 20 m of the Project boundary and nearby areas likely to be affected by the Project. The survey methods used in 2012 were similar to the
Supplemental EIA surveys (2008) and described in 2.1.2.2. Active searches were done during one day and one night in both the wet season (May to June 2012) and dry season (February / March 2012) in
Lung Mei Project Site and Ting Kok East Relocation Site.
ERM also used quantitative surveys, including intertidal transect surveys and intertidal fish surveys.
Quantitative surveys took place during the day also in both the wet and dry seasons, although the number of days taken to complete the quantitative surveys at each site is unclear from the ERM report.
The data from the quantitative surveys carried out by ERM in 2012 were analysed as per 2.1.2.2.
In our view, ERM’s survey design and subsequent data analysis was comprehensive in 2012 and adequately compared the similarity of the ecological profiles of Lung Mei and Ting Kok East.
2.1.2.4. Agriculture, Fisheries, and Conservation Department (AFCD) Ecological Surveys 2012/2013
In December 2012 and January 2013, the Agriculture, Fisheries and Conservation Department (AFCD) conducted field surveys to obtain updated ecological information at Lung Mei. These followed the same
30

procedure used during the Supplemental EIA surveys undertaken in 2008 and described in 2.1.2.2 of this report. It was during these surveys that two seahorse sightings were recorded at Lung Mei Project Site.
2.1.2.5. Marine ecological profile of the Lung Mei Project Site
The four sets of surveys described above, those carried out for the EIA in 2006 (2.1.2.1), Supplemental
EIA surveys in 2008 (2.1.2.2), Further Marine Ecology Investigation in 2012 (2.1.2.3), and AFCD in
2012/2013 (2.1.2.4) together provide a good ecological profile of the Lung Mei Project Site.
We here provide a full summary description of the Project Site, which was missing from ERM’s report.
We also comment on the characteristics of the habitat where seahorses were found in Lung Mei Project
Site, as described in 2.2 of our report (below).
Located at the mouth of Plover Cove, Lung Mei comprises a mix of soft and hard shore habitats with freshwater runoff from Lo Tsz River. The total sea area of the Project Site is 5.4 ha. An artificial / disturbed shoreline covers 1.2 km of Greater Lung Mei and supports a low diversity of species. There are 0.5 ha of mangroves in the Project Site, located near the river mouth of the Shan Liue River and Ting
Kok SSSI. No seagrass areas are located in Lung Mei. Water visibility is minimal, ranging from 0.5 to
1.5 m.
Benthic studies undertaken for the EIA in 2006 within Tolo Harbour and the Channel found the seabed dominated by polychaetes, with low species diversity and low biomass. All species recorded during these surveys were found to occur frequently through this marine ecosystem.
No rare or endemic species were located during any surveys in Lung Mei. A total of three coral species
( Cyphastrea serailia, Oulastrea crispata and Psammocora superficialis ) were found within the Project
Site, with all considered common in Hong Kong. Other benthic fauna recorded in Lung Mei included sponges, ascidians, rock oyster, sea cucumber, urchins and tube anemones. Three species of conservation importance were identified during the Supplemental EIA surveys of 2008, Further Marine
Ecology Investigation in 2012, and the AFCD surveys of 2012/2013: the two spot goby ( Psammogobius biocellatus ); tropical sand goby ( Favonigobius reichei ); and grass puffer ( Takifugu niphobles ).
However, these species are considered common in the Tolo Harbor marine ecosystem and elsewhere in
Hong Kong. The AFCD surveys uncovered additional fish species of conservation concern including one cowfish, eight dragonets and two seahorses.
It appears from the surveys that Lung Mei generally has a lower diversity and abundance of marine species than other surveyed sites in Hong Kong. The intertidal and shallow subtidal fauna found on all surveys were typical of other sandy or rocky shores in Hong Kong. However, compared to the other sites surveyed by ERM in the Tolo Harbour marine ecosystem, Lung Mei had the lowest number of infaunal and epifaunal species, including crustaceans, and the lowest mean abundance and species richness for fish diversity. ERM states that Lung Mei is not a nursery or breeding ground for species in the area due to the lack of seagrass and mangrove habitat. Seagrass beds and mangrove habitats are indeed commonly considered as nursery and breeding grounds for marine species. That said, their absence from the site does not preclude Lung Mei from providing essential habitat for some species.
31

Ecological profiles were consistent across all surveys, in all years, leading us to infer that the characterization of the habitat at Lung Mei Project Site is reasonable.
2.1.3. Characterizing and selecting the Reference Sites and Relocation Site
Our review of the original EIA and subsequent supporting documents suggests that the following steps were taken in deciding that Ting Kok East would serve as the Relocation Site for species of conservation concern from Lung Mei Project Site, including seahorses:

A review of survey data identified twelve sites within Plover Cove and Tolo
Harbour/Channel that had similar habitat characteristics to Lung Mei.

These twelve sites were subject to expert visits to confirm their habitat characteristics, nature of substratum and surrounding environment, as well as abiotic conditions (e.g. wave exposure).

The results of these visits narrowed the site selection to five Reference Sites – which were then subject to active search as described in 2.1.2.2.

The results of the active search further narrowed the list of Reference Sites to just three – which were subject to quantitative surveys , also described in 2.1.2.2.

Based on the results of the quantitative surveys, all three of the remaining Reference Sites were considered to be ecologically similar to Lung Mei. ERM chose Ting Kok East as the final Relocation Site on the basis of its close proximity to the Lung Mei Project Site.
We now review this process.
2.1.3.1. Selecting the Reference Sites
The HK Environmental Protection Department requested that ERM carry out additional surveys to address comments with respect to the original EIA that the ecological character of Lung Mei was considered in isolation, and not compared to that of other soft shore habitats in Plover Cove and Tolo
Harbour/Channel.
A desktop review of aerial photographs, scientific papers, journals and habitat maps presented in various
EIA reports and other studies helped to identify sites within Plover Cove and Tolo Harbour/Channel that had similar habitat characteristics to Lung Mei. Twelve potential sites were selected following the desktop review
1
(
Figure 5
). ERM qualified biologists visited each of these twelve sites from February to
March 2008 to investigate and verify their habitat characteristics, nature of substratum and surrounding environment, as well as abiotic conditions (e.g. wave exposure). The results of these visits identified five locations referred to as “Reference Sites” – Ting Kok East, Shuen Wan, Wu Chau, Yung Shue O North
and Lai Chi Chong – to be compared with the ecological value of the habitat at Lung Mei (
Figure 5
).
In our view, ERM’s process for selecting the five Reference Sites was comprehensive and sound.
1 Additional Information in response to EPD’s letter ref.(92) in EP2/N5/C/46. Pt.4 , Table B3, p.B-4
32

2.1.3.2. Methods for characterizing the Reference Sites
Additional characterization was needed in order to evaluate the potential of the five Reference Sites as sites for relocating the species of conservation concern found at Lung Mei Project Site (which at this point did not include seahorses). First, a site map showing the nature of the substratum for each of the five Reference Sites was prepared by ERM. ERM then carried out active searches (as part of the
Additional EIA surveys in 2008, as described in 2.1.2.2) at these five sites to examine their intertidal faunal diversity
2
.
The results of active searches indicated that three of the five Reference Sites – Ting Kok East, Yung
Shue O North and Lai Chi Chong – shared similar ecological profiles with the Lung Mei Project Site as determined by comparing the nature of the substratum, habitat characteristics, surrounding environment and faunal composition.
Therefore these three sites were subject to quantitative surveys of their intertidal area as described in
2.1.2.2 – including transects to describe habitat, benthic cores, and crustacean and fish surveys.
Since ERMs quantitative surveys were carried out in 2008, in December 2012 and January 2013 the
AFCD conducted field surveys, using the same techniques as described in 2.1.2.2, to update the ecological information at Ting Kok East, Yung Shue O North and Lai Chi Chong. It was during these surveys that seahorses were sighted at Ting Kok East, Yung Shue O North and Lai Chi Chong.
In our view, ERM’s process for narrowing down the Reference Sites to just three was comprehensive and sound. It is also valuable that AFCD was able to update the ecological information at the three sites.
2.1.3.3. Marine ecological profiles of the Reference Sites
The results of the quantitative surveys of the three Reference Sites that were considered ecologically similar to Lung Mei are summarized below.
Ting Kok East
Located closest to Lung Mei and within Plover Cove, Ting Kok East comprised of a mix of soft and hard shore habitats with a very gentle gradient, very similar to Lung Mei. High and mid-intertidal zones mainly consisted of boulders and cobbles with a sandy bottom. A large area of mangroves, and freshwater runoff from Shan Liu River can also be found in the area.
Compared to other relocation sites, Ting Kok East had moderate diversity, for intertidal and shallow subtidal fauna. The continuous patches of mangrove habitat is thought to provide a nursery / breeding ground for many species. The three species of conservation concern, the two spot goby ( Psammogobius biocellatus ), tropical sand goby ( Favonigobius reichei ) and grass puffer ( Takifugu niphobles ) were observed, and there were eight sightings of the spotted seahorse H. kuda .
Yung Shue O North
2 Additional Information in response to EPD’s letter ref.(92) in EP2/N5/C/46. Pt.4 , Table B3, p.B-7
33

Located within Tolo Harbour at Three Fathoms Cove and opposite to Wu Chau, Yung Shue O North contains mixed soft and hard shore habitats with freshwater runoff from one large natural stream and a larger area of mangroves. The mid intertidal zone consists of boulders and rubble with a sand bed while the low intertidal zone consists mainly of fine sand with boulders and rubbles.
Compared to other potential relocation sites, Yung Shue O North has comparatively moderate diversity for intertidal and shallow sub-tidal fauna, and continuous patches of mangrove habitat. The mangrove habitat is thought to be a nursery and breeding ground for many species. It also has a natural and unpolluted stream close by. The three species of conservation concern, the two spot goby
( Psammogobius biocellatus ), tropical sand goby ( Favonigobius reichei ) and grass puffer ( Takifugu niphobles ) were observed , and there were twelve sightings of the spotted seahorse H. kuda .
Lai Chi Chong
Located within Tolo Channel and next to the Sai Kung West Country Park, Lai Chi Chong contains mixed soft and hard shore habitats with a gentle gradient in some areas. A thin sand beach can be found in the backshore with some boulders. The mid intertidal zone consists of boulders and rubble with sand bottom while the low intertidal zone consists mainly of fine sand with boulders and rubbles. Freshwater run-off from natural streams and mangroves are found in the area.
Compared to other potential relocation sites, Lai Chi Chong had comparatively high diversity for intertidal and shallow sub-tidal fauna along with small patches of mangrove and seagrass habitats. It also has a natural and unpolluted stream close by. The mangrove habitat is thought to be a nursery and breeding ground for many species. The three species of conservation concern, the two spot goby
( Psammogobius biocellatus ), tropical sand goby ( Favonigobius reichei ) and grass puffer ( Takifugu niphobles ) were observed, and there were five sightings of the spotted seahorse H. kuda .
In our view, the three Reference sites are indeed ecologically similar, however AFCDs survey approach does not allow us to assess nor compare the relative abundance of seahorses at the three sites.
2.1.3.4. Selecting Ting Kok East as the Relocation Site
In the Precautionary Mitigation Measures Report provided by ERM, it lists the set of criteria used to select the Relocation Site for any seahorses that may be found in Lung Mei Project Site. These criteria included similarity in water depth, water current speed, proximity to the Project Site and biological characteristics (e.g. habitat types) and features such as species composition . Based on these criteria, all three Reference Sites were considered potentially suitable to receive the seahorses. Additionally, none of these sites was predicted to experience ecological impacts as a result of the Project. Thus ERM made the decision for the Relocation Site on its proximity to the Project Site, seeking to minimize transport time for relocated fishes. On this basis they selected Ting Kok East, which is nearest to the Project Site (<
500 m).
34

After ecological similarity, distance to Project Site is certainly one criterion by which ERM could further narrow the three Reference Sites to one final Relocation Site. However, we would also encourage evaluation of the following:
Expected and anticipated threats at the proposed Reference Sites. It is important that the proposed
Reception Site be free of deleterious influences, and expected to stay so.
Possible predators in the Reception Site, which might limit success of any Relocation.
Abiotic factors such as temperature, salinity, depth and current. That said, the Sites are close together along the coast of one sheltered bay and unlikely to differ meaningfully in any of these variables.
Distance to the nearest Marine Protected Area or other management space. Indeed an MPA might be a good Relocation Site.
2.1.4. Habitat comparison between Lung Mei and Ting Kok East
Ensuring similarity between the a Project Site and a proposed Relocation Site is essential because seahorses, as with most animals, prefer habitats where they have an ample food supply, shelter from predation, and the chance to encounter a mate. In this section we summarize the methods used to compare the similarity of the relocation site and Lung Mei while synthesizing the results of these surveys.
To ensure that the proposed Relocation Site and Project Site had similar ecological and biological characteristics, ERM carried out additional investigations in both the wet and dry seasons of 2012 to compare the similarity of the two sites (see 2.1.2.3 for survey details).
The results of these ecological surveys revealed that the Project Site and Relocation Site supported similar habitats with similar species assemblages. Quantitative data obtained from the intertidal transect surveys showed that the abundance, species richness, diversity, evenness and structure of epifauna assemblages were similar between Lung Mei and Ting Kok East. Similarity was confirmed by lack of significant differences in parametric tests, and low r-values of non-parametric, multivariate analyses of community data. The three fish species of conservation importance recorded during the 2008 additional surveys (i.e. two-spot goby, Indo-Pacific tropical sand goby and grass puffer) were also observed during the 2012 active search surveys at both Lung Mei and Ting Kok East.
We consider that the available background documents and new information provided by ERM surveys are sufficient to confirm the similarity of ecological and biological characteristics of Lung Mei and
Ting Kok East.
35

2.2. CHARACTERIZING SEAHORSES AT LUNG MEI PROJECT SITE AND TING KOK
EAST RELOCATION SITE
After the public and AFCD reported the presence of seahorses at the Project Site, ERM planned and carried out seahorse surveys to characterize the seahorses and their habitats at Lung Mei Project Site and
Ting Kok East Relocation Site, and address information gaps identified in their Phase 1 Seahorse
Review Report . The information gaps identified by ERM included:

Establishing site and species specific information.

Establishing the marine ecological profile of the Project Site and Relocation Site and describe the characteristics of habitats of the seahorse species.

Investigating if an interim relocation site/facility might be beneficial to the survival of seahorses in sensitive conditions and the availability of such site/facility.

Exploring the feasibility of seahorse tagging for the post-relocation monitoring based on findings of any local tagging exercise, if available.

Collecting information on occurrence and abundance of seahorses in relation to: o time of day (day or night); and o tidal conditions.
ERM provided critical baseline information for seahorse biology and ecology at Lung Mei Project Site and Ting Kok East Relocation Site
. ERM did a thorough search for seahorses at both sites. Its surveys should also have included areas in Greater Lung Mei beyond the Project Site. Although ERM’s work serves as a thorough snapshot, the lack temporal (throughout the year) and spatial (throughout Greater
Lung Mei) replication of the surveys limits understanding
about the biology of seahorses at the Project and Relocation Sites.
2.2.1. ERM’s seahorse surveys at Lung Mei Project Site and Ting Kok East Relocation Site
2.2.1.1. Methods
Both intertidal and subtidal surveys were undertaken at the Project and Relocation Sites in search of seahorses in June 2013. Surveys were conducted in all major habitat/substrate types in the Project and
Relocation Sites. Habitat types in the surveyed area included bare sand, soft bottom with scattered rubble, sand with boulders and rubble, upper shore/sand beach, and cobble/boulder zone. Encountered seahorses were identified to species level and photographed. Survey effort was not equal between the intertidal and subtidal surveys and therefore seahorse sightings were standardized per unit search effort, which ERM defined as “number of man-hours”.
Qualitative intertidal surveys covered both the intertidal and shallow subtidal zones from 0.5 to 2 m chart datum depth, for a total search area of approximately 10,000 m
2
(50 x 200 m) (
Figure 1
;
Figure 2
).
Three days and three nights were spent surveying the intertidal area at Lung Mei Project Site in June
2013.
36

Quantitative subtidal surveys were conducted using underwater visual census by scuba diving. Four dives were conducted in a 30,000 m
2
(150 x 200 m) survey area covering a depth range of 0.5-6 m chart
datum – two during the day and two at night ( Figure 1 ;
Figure 2 ). Thirty belt transects of 5 x 200 m were
executed to cover the entire 30,000 m
2 survey area. For these quantitative surveys, sighted seahorses were recorded by video. Habitat was only characterized during the daytime surveys.
2.2.1.2. Results
Lung Mei Project Site: Four seahorses, identified as H. kuda , were sighted in the Project Site – one
during an intertidal survey at high tide and three during subtidal dives (
Figure 1
). Two sightings
occurred at night, one close to sunrise and the other close to sunset. Three of these sightings occurred on the same day. There is the possibility that some of these were resightings of the same individual, although size and sex distinctions indicate that there were at least three seahorses at Lung Mei.
Seahorses in the Project Area were found in shallow, subtidal areas ranging in depth from 0.5 to 3 m.
However, seahorses may also occur in the deeper, subtidal areas outside the designated Lung Mei
Project Site, which should also have been surveyed. If seahorses do occur in areas immediately outside the Project Site, they may also be indirectly affected by the Project (e.g. runoff) or removal of seahorses from within the Project Site with which they might interact. We discuss these potential impacts in more detail in Phase 3 of our report.
The seahorses at Lung Mei were found in a habitat of mixed sand with boulders and rubble in the intertidal area and in soft bottom habitat with tunicates, shells and debris in subtidal areas. All seahorses were recorded near the mouth of the Shan Liu Stream at the western edge of the Project Site, perhaps indicating a preference for this lower-salinity environment.
Three out of the four individual H. kuda (two females, and one male) sighted in the Lung Mei were larger than the mean size of sexual maturity for this species as described in 1.7.1 of this report, but ERM reported no pregnant seahorses. The other individual, a female, was close to size of sexual maturity.
ERM notes, however, that reported seahorse heights may not be accurate because of a desire to minimize handling time of seahorses.
Ting Kok East Relocation Site: Eight seahorses identified as H. kuda were encountered during the
seahorse surveys at Ting Kok East (
Figure 2
). There is the possibility that some of these were
resightings of the same individual, although size and sex distinctions indicate that there were at least five seahorses at Ting Kok East Relocation Site. All seahorses were found in a habitat with mixed sand and rubble, and additional debris (dead shells, urchins). The two seahorses found during the intertidal survey at high tide were reported in water depths of 0.5 m. The remaining six individuals were found in waters depths of 2.0 – 2.5 m during the subtidal surveys. Four seahorses were recorded during night surveys and four seahorses were recorded during the day.
All individuals appear to have reached size of sexual maturity, but ERM reported no pregnant seahorses, and an even sex ratio of 1:1 (four males to four females) was observed. This sex ratio should be noted with caution, as ERM Consulting admits they are not confident in determining the sex of the seahorse in cases where the male is not clearly pregnant.
37

2.2.1.3. Project Seahorse review of ERM’s seahorse surveys
While we appreciate ERM’s determination in searching for seahorses, we are able to make a number of recommendations that would improve the coverage, reliability and accuracy of the surveys.
We have discovered that the standard transect swims that ERM employs are not an effective means to search for seahorses[94]. Project Seahorse instead recommends haphazard directional swims – straight lines are not necessary but avoid backtracking - with measured effort: the distance travelled and search time [132]. “Distance traveled” is simply the distance covered while searching for seahorses[132].
“Search time” is the time spent actively searching for seahorses [132].
Once a seahorse is found, we recommend focusing effort in that area; one of the best predictors of finding a seahorse is searching in close proximity to another individual[94]. Once a seahorse is found,
Project Seahorse recommends searching in increasing concentric circles out to 50 m away from the individual. Some seahorse species are known to occur in pairs and searching near another individual can increase the likelihood of encountering naturally clustered species. A pair can be inferred if a male and female seahorse are observed to interact frequently with one another over many days.
We recommend surveying an area multiple times to ensure proper characterization of seahorses and their habitats. Seahorses are cryptic, rare and patchily distributed. Because seahorses are also elusive
(nocturnal, camouflaged, hidden beneath rubble), it can be very difficult for even the highly trained observer to spot them[132].
Even with ERM’s diligent efforts, few conclusions can be drawn about the biological characteristics of seahorses at the Project and Relocation Sites because of the lack of temporal (throughout the year) and spatial (throughout Greater Lung Mei) replication of the surveys.
Understanding the seahorses in Lung Mei would require additional seahorse surveys outside the Project
Site, but within Greater Lung Mei (
Figure 1
). The Project Brief describes that the study area “covers the
intertidal areas within 20 m of the Project Site boundary and other areas likely to be affected by the
Project (e.g. works laydown areas)”. Yet coastal development can have effects that reach far beyond the physical project area (e.g. water quality). Additional seahorses may live within Greater Lung Mei
(outside the Project Site) and have the potential to move into the Project Site, or interact socially with seahorses in the Project Site.
We note three other areas of uncertainty with ERM’s seahorse surveys:
 The possibility that ERM’s tally includes resightings of individual seahorses means that the total numbers of seahorses at both sites remain unknown, although size and sex distinctions indicate that there were at least three seahorses at Lung Mei Project Site and five at Ting Kok East
Relocation Site.
 The sex ratio in the Sites remains open to some question, given ERM’s comments about its difficulty in determining sex when male seahorses are not pregnant (but see below).

The very limited temporal coverage of the surveys means that lack of observed breeding individuals may not reflect the Sites’ importance for reproductive activity over the entire year.
38

Upon encountering a seahorse, it is important to record species identification, size, sex, holdfast, and depth.

To confirm species identity, take two photos of the seahorse. The first photo should be of the side profile of the seahorse with a ruler[132]. Make sure the facial spines and the coronet can be clearly seen in the photo[132]. The second photograph should be a close-up of the side profile of
the head, with clearly visible facial spines (especially check spines) and coronet (
Figure 7
)[132].

Seahorses are most easily measured using torso length (also known as trade height:
Figure 7
).
Torso length is the distance between the top of the coronet and the last trunk ring at the base of the dorsal fin, and can usually be measured by placing a ruler parallel to the length of the seahorse[132]. Record torso length to the nearest 0.5cm. Torso length can also be measured from a photo of the seahorse with a scaled object in the background.

Recording the sex of adult seahorses is straightforward with some practice. Male seahorses have
a brood pouch under the belly which females lack (
Figure 7
)[132]. The brood pouch is apparent
even if the male is not pregnant. As well, female trunks end abruptly, meeting the tail at right angles, just at the base of the dorsal fin[132]. Male trunks extend posterior to the base of the dorsal fin, tapering to the tail[132]. Record the sex as unknown, when in doubt.

If the seahorse is male, record whether he is pregnant (swollen brood pouch) or not.
Figure 7. Diagram indicating the distinguishing characteristics of a seahorse, and how to measure “Torso Length”.
Diagrams by Shedd Aquarium/Project Seahorse.
39

2.3. PHASE 2 SUMMARY
Our evaluation in this second section provides the following contributions:
 We conclude that the characterization of the ecological profiles of Lung Mei Project Site and
Ting Kok East Relocation Site were adequate, although temporally limited.
 We confirm the similarity of biological / ecological characteristics of Lung Mei Project Site and
Ting Kok East Relocation Site.
 We suggest additional criteria and caveats to the good approaches that ERM used to identify suitable relocation sites for the relocated seahorses, in addition to proximity to Lung Mei Project
Site.
 We consider that ERM did a thorough search for seahorses at the Lung Mei Project Site and Ting
Kok East Relocation Site, and provide a good snapshot of seahorses at one time.
 We point out that any conclusions about the biological characteristics of seahorses at the Lung
Mei Project Site and Ting Kok East Relocation Sites are limited due to the lack of temporal
(throughout the year) and spatial (throughout Greater Lung Mei) replication of the surveys.
 We suggest enhancements to the seahorse surveys in support of gathering useful data for evaluating impacts from construction activities on seahorse populations.
With this information in mind, we turn next to evaluating the possible impacts of the Project and the proposed remediation/relocation techniques on seahorses in Lung Mei Project Site, Ting Kok East
Relocation Site and Greater Lung Mei.
40

** HOME RANGES
* RSG guidelines
3.1. INTRODUCTION
In this third (and final) section of our report we summarize the potential impacts of the Project on seahorses, with special reference to ERM’s Phase 3 Precautionary Mitigation Measures Report . The section includes the following analyses, with information drawn from previous studies and expert opinion:

Identify possible impacts from construction activities on seahorses within the Lung Mei Project
Site, Ting Kok East Relocation Site and Greater Lung Mei (outside the Lung Mei Project Site).
Our comments on the impacts are made assuming no relocation of seahorses in Lung Mei
Project Site.

Identify possible impacts associated with relocating seahorses from Lung Mei Project Site to
Ting Kok East Relocation Site, considering also Greater Lung Mei.
 Enhance ERM’s guidelines for relocation and monitoring, as remedial measures for the Project.

Provided an appendix of sample monitoring forms and references.
We note a great need for CEDD to define its goal, objectives and metrics for remedial efforts and particularly for seahorse relocation.
We infer that the Project should not pose significant threats to seahorse populations in Tolo Harbour or
Hong Kong waters more generally. We cannot be certain that individual seahorses from Lung Mei
Project Site will remain and/or thrive in Ting Kok East Relocation Site but their numbers are low enough that their survival (or lack thereof) should not affect population persistence for H. kuda in Tolo
Harbour or Hong Kong more generally. We propose monitoring to help determine the actual response of the relocated individuals, and of those seahorses in the Relocation Site. Such monitoring would be globally important in helping to improve the effectiveness of relocation planning for seahorses, while also gathering useful biological and ecological information about seahorses in Hong Kong.
3.2. POSSIBLE IMPACTS OF THE PROJECT
In this section we probe the possible impacts of the Project on seahorses at the Lung Mei Project Site,
Ting Kok East Relocation Site, and Greater Lung Mei (
Figure 1
;
Figure 2
). We consider three time
scales:

Immediate impacts: Caused by the Project and occur at same place and time. This set of impacts could occur over the entire duration of Project, taking months for some activities.

Delayed impacts: Caused by the Project and occur at same place – but deferred in time. This set of impacts will emerge after direct Project activities have ceased.
41


Future impacts: Caused by later maintenance or enhancement activities associated with the
Project.
We evaluate each potential impact as causing low, medium or high concern in terms of its effect on the local seahorses, remembering that seahorse numbers are very small and unlikely to affect population persistence of seahorses in Tolo Harbour or Hong Kong.
We understand that the Project will involve the following activities:

Sewerage construction project to improve water quality in anticipation of the Project
(scheduled for November 2010)[3];

Construction of 200 m long beach with groyne at each end, including dredging and sandfilling[1];

Construction of a culvert at the eastern side, and small culvert and open drainage channel at the western end to collect and divert surface run-off from upstream locations[1];

Construction to create the beach and build beach facilities, kiosk, car park, and road improvements[1];

Relocation of 12 mooring buoys to outside the Lung Mei Project Site[1].
The duration and timing of the Project are important in evaluating the extent and severity of possible impacts on seahorses. We can only base our opinions and input on information provided by the Hong
Kong CEDD. According to the Development of a Bathing Beach at Lung Mei, Tai Po
Environmental, Drainage and Traffic Impact Assessments Investigation (EIA) , the construction and completion of the beach and its supporting facilities will take two years to complete[3]. Dredging is expected to take two months to produce an estimated 10,500 m
3 of marine sediment, and it is anticipated that sand filling of the beach will take approximately four months[3]. The Project will result in a loss of
4.7 ha of coastal waters and relocation of 12 mooring buoys[3].
3.2.1. Possible impacts on seahorses at the Lung Mei Project Site, assuming no relocation
3.2.1.1. Immediate Impacts
The proposed Project could have some immediate impacts on seahorses at the Lung Mei Project Site.
We will briefly discuss the possible impacts of three main activities – dredging, sand filling, and other construction activities – and explain our evaluation of their possible effects. Most such activities generate low concern but we have do moderate concern about the possible effects from noise associated
with dredging and sand filling, and habitat loss from sand filling (
Table 2
).
Dredging
Dredging may cause habitat loss, noise, increased turbidity, and changes in water quality (
Table 2
).
Sediment removal may, of course, kill any seahorses in the path of the dredger, which would be of high concern for the individual seahorses. Habitat is damaged through sediment removal during dredging but usually recovers rather quickly, making it low concern[133-136]. Otherwise, noise levels may be of some concern as seahorses are known to be stressed by noise pollution [96, 97] (see 1.9.4). In contrast,
42

turbidity and water quality changes are unlikely to be very problematic on the temporal and spatial scale reported here [89].
Habitat loss for seahorses associated with dredging of sandy and muddy bottoms that are characteristic of Lung Mei Project Site is a low level concern because of the temporary nature of the impact and the minimal spatial area to be dredged[3]. Although dredging can result in both temporary and permanent destruction of the seabed, full recovery post-dredging has been documented[133, 134]. Dredged areas and the associated biological communities vary in the speed of their recovery but sandy areas can expect to show recovery of most benthic species in two to three years [136]. However, in studies with low intensity disturbance, such as the small area to be dredged in a brief time period for this Project, benthic biota can recover within one[135] to two months[134].The Project EIA (2007) noted that the risk from dredging was low or negligible because the habitat was already poor and the affected area is small[3]
The implications of noise pollution on seahorses and other syngnathids have yet to be fully assessed, but could be of moderate concern for the individuals involved. Sound travels faster and further in water than in air, and the noise from dredging is known to travel large distances underwater and is considered to be of low frequency[137]. The low mobility of these fishes means they have particularly limited ability to relocate[125]. Chronic levels of stress become apparent in fish exposed to persistent low frequency noise[138, 139]. Indeed, seahorses exposed to loud noise in aquariums for one month demonstrated clear physiological, chronic stress responses with reduced mass and body condition[97] and spent more time moving, an indication of irritation[97]. Reproductive and feeding rates had not, however, declined by the end of the experiment[97]. In the wild, larval syngnathids that are about to settle out of the plankton certainly distinguish among noises, preferring high-frequency over low-frequency trap noise on coral reefs[98]. The implications of such distinctions have not, however, been assessed.
Turbidity and water quality changes associated with dredging will probably pose only short-term threats
(
Table 2
). Once dredging has ceased, it is anticipated that turbidity and water quality around dredging
sites will return to pre-dredging levels[3]. The only caveat would be if the dredging created a release of toxic or problematic chemicals. At least some syngnathids may respond poorly to chemical pollutants, eutrophication or other changes in water quality and associated visibility[22, 125]. It is unclear whether seahorses have any particular sensitivity to environmental change (i.e. indicator species) but they are certainly vulnerable to stress, which often manifests as disease[22] (see1.5.1 & 1.5.2).
Sand Filling
Sand placement may, of course, kill any seahorses in its path, raising high concern for the individuals involved. We lack information on how seahorses would react to sand filling, but seahorses usually respond to threats by staying stationary [94]. Otherwise, sand filling might create three main impacts on seahorses at the Lung Mei Project Site: habitat loss, increased turbidity, and changes in water quality
(
Table 2
).
Sand filling activities are anticipated to result in a loss of 4.7 ha of coastal waters in the Project Site, some of which includes possible seahorse habitat. This raises a moderate concern on a local scale because the injury to habitat from sand filling persists far longer than that from dredging[134, 135].
ERM reports that there is similar habitat within Plover Cove in terms of biophysical properties but we do not know whether (and how) seahorses use or do not use other areas. There is no information on how sites for seahorse foraging, breeding and recruitment are distributed within Plover Cove (as discussed in
2.2.1.3).
43

Additional Construction Activities
The three main activities embedded in the Project may also have impacts on seahorses at the Lung Mei
Project Site: (i) land based construction activities associated with parking lot and bathing facilities, (ii)
installation of the shark net, and (iii) relocation of the mooring buoys (
Table 2
). None of these is likely
to present serious long-term problems, and we have ranked them to be of low concern. The impacts from land-based construction activities may include spills of oils, chemicals and lubricants that run-off into the intertidal waters of the Lung Mei Project Site[3]; this run-off would be associated with decreases in water quality. Shark nets are known to act as additional seahorse habitat[105]; therefore installing shark nets may alter or modify current foraging and breeding grounds for seahorses.
Relocation of the mooring buoys (and the mooring lines that may also act as additional seahorse habitat) may cause temporary modification of current foraging or breeding grounds for seahorses.
3.2.1.2. Delayed Impacts
Delayed impacts on seahorses at the Lung Mei Project Site would be attributable to the same three main activities that may generate immediate impacts: dredging, sand filling, and other construction activities such as installation of the shark net and relocating the mooring buoys. Most such activities generate low concern but we have do moderate concern about the possible effects from noise associated with
dredging and sand filling, and habitat loss from sand filling (
Table 2
).
Dredging
The only delayed effect of dredging on seahorses at the Lung Mei Project Site would probably be the chronic stress associated with noise pollution, and causes moderate concern. Even two months of noise pollution from dredging may affect seahorses in the Lung Mei Project Site[97], not least because the low mobility of these fishes means they have particularly limited ability to escape noise (see 3.2.1.1).
Sand Filling
Although sand filling will only last a short time, the operational noise and ensuing habitat loss may have longer term impacts on seahorses, causing our evaluation of this impact as a moderate level of concern
(see 3.2.1.1). The loss or degradation of foraging or breeding grounds could lead to slower growth or lower reproductive success in seahorses in the long run[125].
Additional Construction Activities
We anticipate that two main activities may have delayed negative and positive impacts on seahorses in the Lung Mei Project Site: improvements in water quality (initiated before the physical activities on the
Lung Mei Project Site) and installation of the shark nets (
Table 2
).
A sewerage construction project was scheduled to be completed by November 2010 with the intention of improving water quality to a level that would allow Lung Mei Project Site to serve as a bathing beach.
If effectively completed, this should lead to overall improvements to water quality in Greater Lung Mei, which may reduce current seahorse stress levels of living in conditions with poorer water quality. Over time, reductions in stress levels may lead to increased reproductive success of seahorses and persistence in Greater Lung Mei.
44

The installation of shark nets over time may lead to the creation of new seahorse habitat, as has happened elsewhere[105]. Such an array of holdfasts may increase foraging and breeding success for seahorses in the Lung Mei Project Site.
3.2.1.3. Future Impacts
The only likely impacts in the foreseeable future would come from maintenance of shark nets, although this seems to be of low concern. There is currently no plan for dredging, sand filling or groyne maintenance to support the beach[3]. Any later decision to embark on such activities would necessitate
consideration of their impacts as when they were first undertaken at Lung Mei Project Site (
Table 2
).
Maintenance of shark nets has previously had a negative impact on seahorse populations, by displacing those living on this new habitat[105]. The real impact of shark net maintenance will depend on whether the nets are enhancing seahorse numbers or merely acting as fish attraction devices, spatially concentrating the same number of seahorses. In the former case, net maintenance may prove problematic. For example, the numbers of H. abdominalis and H. whitei declined significantly upon replacement of a swimming net in Australia, with recovery of the latter population taking >15 months[105]. Also in Australia, the large number of seahorses that occupied anti-predator nets at farms for Atlantic salmon ( Salmo salar ) died when the nets were removed from the water to be treated against fouling[111]. In Hong Kong, it will be important to trial the emerging (and still relatively untested) guidelines about maintaining shark nets with consideration for resident seahorse populations[105].
3.2.2. Possible impacts on Seahorses in Ting Kok East Relocation Site
Seahorses already resident in Ting Kok East Relocation Site would face some impacts (immediate, delayed and future) similar to those in the Lung Mei Project Site itself, raising only low levels of
concern (
Table 2
). We are not aware of any mitigation plans for addressing potential impacts on the
seahorses from Ting Kok East Relocation Site.
The only immediate or delayed impacts might come from the noise associated with dredging and sand filling activities. The noise from these activities is known to travel large distances underwater and the low mobility / site fidelity of seahorses limits their potential to escape noise. The result may be chronic stress for the animals, and all the problems that creates (see 3.2.1.1).
We foresee no future impacts on seahorses at Ting Kok East Relocation Site from later construction or maintenance activities in Lung Mei Project Site.
3.2.3. Possible impacts on seahorses elsewhere in Greater Lung Mei
Seahorses living near the boundaries of the Lung Mei Project Site in Greater Lung Mei would face many of the same impacts (immediate, delayed and future) as those in the Lung Mei Project Site itself, and
45

raise the same level of concern (
Table 2
). We are not aware of any mitigation plans for addressing
potential impacts on these nearby seahorses.
Some impacts will be felt if seahorses in Greater Lung Mei spend time interacting with the seahorses in
Lung Mei Project Site. Seahorse pairs may, for example, straddle the boundary of the Lung Mei Project
Site, such that any damaging effects on the seahorses in Lung Mei Project Site would affect a partner in
Greater Lung Mei. Moreover, if Greater Lung Mei seahorses visit Lung Mei Project Site for social interactions or foraging, the impacts of habitat loss due to sand filling in Lung Mei Project Site may also extend to the visitors. On the other hand, shark nets and mooring buoys in Lung Mei Project Site may generate new habitat for Greater Lung Mei seahorses --- and maintenance or re-siting of these features could cause eventual problems for Greater Lung Mei seahorses (see 3.2.1.1).
Other impacts may be felt because a threat extends beyond the boundary of the Lung Mei Project Site
(e.g. with noise from dredging and sand filling, which raises moderate concern). We do not anticipate turbidity impacts from dredging, given that a silt curtain will be deployed to keep impacts of sediments to the Lung Mei Project Site. As well, the environmental impact assessment predicts all impacts from dredging will be maintained in the Lung Mei Project Site[3]. The impacts from construction activities may, however, include spills of oils, chemicals and lubricants that extend beyond the Lung Mei Project
Site; this run-off would be associated with decreases in water quality[3]. In contrast, the sewerage construction project should generate a net benefit to the seahorses[3].
3.2.4. Additions to ERM’s Precautionary Mitigation Measures Report
We have enhanced and strengthened ERM’s assessment of possible impacts on seahorses as follows:
• We insisted that underwater noise from dredging and sand filling could indeed present a risk to individual seahorses, which cannot easily escape the noise (in contrast to many other fish species[125]).
• We added consideration of the impacts on seahorses associated with installation and maintenance of the shark net at the Lung Mei Project Site and Greater Lung Mei (just outside the shark net).
• We took a comprehensive view of the possible impacts of the Project on seahorses in Ting Kok East
Relocation Site, both because of their proximity to Lung Mei Project Site and their location in the proposed Ting Kok East Relocation Site.
• We explored possible impacts of the Project on seahorses elsewhere in Greater Lung Mei, which had been overlooked in the ERM report, despite the animals’ proximity to Project activities.
46

Table 2. Possible impacts of the Project on seahorses at the Lung Mei Project Site, Ting Kok East Relocation Site, and Greater
Lung Mei. In this evaluation, we assume no remedial activities or relocations. We then provide our level of concern about each impact for the individual animals involved. Our evaluations are based on the facts provided to us in the EIA. We have identified five possible negative effects and two possible positive effects of construction activities, as follows:
Neg 1 – direct mortality;
Neg 2 – habitat loss or modification, and its consequences;
Neg 3 – increased stress for individuals, and its consequences;
Neg 4 – reduced visibility affecting foraging success;
Neg 5 – decrease in water quality;
Pos 1 – increase in water quality; and
Pos 2 – creation of new habitat.
Possible impacts of the Project on individual seahorses, assuming no remediation
Immediate Lung Mei Project Site Ting Kok East
Relocation Site
Greater Lung Mei Level of
Concern
Dredging
Extraction of sediment
Noise
Neg 1, Neg 2
Neg 3
Not Applicable Neg 2
Neg 3 Neg 3
Neg 1 – High
Neg 2 – Low
Moderate
Turbidity
Chemical leaks from machinery
Sand Filling
Physical placement of sand
Neg 4
Neg 3, Neg 5
Neg 1, Neg 2
Not Applicable Not Applicable
Not Applicable Neg 3; Neg 5
Not Applicable Neg 2
Low
Low
Neg 3 Neg 3
Not Applicable Not Applicable
Not Applicable Neg 3; Neg 5
Neg 1 – High
Neg 2 –
Moderate
Moderate
Low
Low
Noise
Turbidity
Chemical leaks from machinery
Other Construction Activities
Neg 3
Neg 4
Neg 3; Neg 5
Chemical leaks from machinery
Shark net installation
Neg 3; Neg 5
Neg 2
Relocation of mooring buoys Neg 2
Delayed
Dredging
Noise Neg 3
Sand filling
Physical placement of sand Neg 2
Noise Neg 3
Not Applicable Neg 3; Neg 5
Not Applicable Neg 2
Not Applicable Neg 2
Neg 3 Neg 3
Not Applicable Neg 2
Neg 3 Neg 3
Low
Low
Low
Moderate
Moderate
Moderate
Other Construction Activities
Sewerage installation (2010) Pos 1
Shark net installation Pos 2
Future
Maintenance of shark nets Neg 2, Pos 2
Maintenance of groynes (if eventually undertaken)
Neg 2, Neg 3
Not Applicable Pos 1
Not Applicable Pos 2
Not Applicable Neg 2, Pos 2
Not Applicable Neg 2, Neg 3
Low
Low
Moderate
Low
47

3.3. POSSIBLE IMPACTS OF THE REMEDIATION / RELOCATION PLAN
3.3.1. Possible impacts of relocation on seahorses from the Lung Mei Project Site
3.3.1.1. Immediate Impacts
The proposed remediation / relocation plan would have immediate impacts on seahorses currently found
in Lung Mei Project Site (
Table 3
). The most obvious of these is increased stress from capture, handing,
tagging, transport and release activities. There is a further risk that breeding pairs may be separated as a consequence of the relocation exercise, especially if one partner is not moved (perhaps because it lives just outside the Project area, elsewhere in Greater Lung Mei). Then there is the risk that the seahorses relocated from Lung Mei Project Site may encounter predation, face aggression or increased competition with existing seahorses from Ting Kok East Relocation Site, or be exposed to new disease transmission from the seahorses at the Ting Kok East Relocation Site.
All experience with seahorses suggests that none of these immediate impacts generates great concern.
Seahorses are frequently removed from the water and handled in the course of field research, and then resume their holdfasts and reproductive cycles seemingly unperturbed[21, 34, 140-142].
3.3.1.2. Delayed Impacts
The greatest risk for seahorses relocated from Lung Mei Project Site is that they may fail to thrive
(
Table 3
). They could encounter new predators, difficulty in foraging, disruption to breeding, exposure
to new diseases or simply fail to settle down in the new habitat. There is also a small risk that their reproduction might be so compromised as to penalize their fitness. Such disadvantages could either lead some seahorses relocated from Lung Mei Project Site (and perhaps even some resident seahorses from
Ting Kok East Relocation Site) to leave the Ting Kok East Relocation Site and disperse elsewhere or to the death of some seahorses. On the other hand, adding seahorses to Ting Kok East Relocation Site might result in a greater critical mass of seahorses for reproductive opportunities.
3.3.1.3. Future Impacts
The only obvious future impact direct from the current Project would be the ongoing stress from
monitoring but this is not thought to be a large concern (see Table 3 ).
3.3.2. Possible impacts of relocation on seahorses in the Ting Kok East Relocation Site
In terms of immediate and delayed impacts, the seahorses from Ting Kong East Relocation Site are
unlikely to be disturbed by capture, measurements or tagging (see
Table 3
). On intermediate and
delayed time scales, there is some risk that these seahorses from Ting Kong East Relocation Site may face aggression or increased competition with the introduced seahorses from Lung Mei Project Site, or
48

be exposed to new disease transmission from the relocated seahorses. On the other hand, one benefit from the arrival of seahorses from Lung Mei Project Site may be access to more mates.
3.3.3. Possible impacts of relocation on seahorses elsewhere in Greater Lung Mei
The relocation of seahorses from Lung Mei Project Site will affect those living elsewhere in Greater
Lung Mei primarily through pair disruption, if only one member of a pair is relocated (
Table 3
). This
may reduce the reproduction of seahorses in the area. Again, in terms of immediate and delayed impacts, the Greater Lung Mei seahorses are unlikely to be disturbed by capture, measurements or tagging.
3.3.4. Additions to ERM’s Precautionary Mitigation Measures Report on relocation activities of seahorses from Lung Mei Project Site to Ting Kok East Relocation Site
We have enhanced and strengthened ERM’s assessment of possible impacts on seahorses in the
Proposed Mitigation Plan as follows:

We raised the points that the relocation of the seahorses from Lung Mei Project Site might generate aggression among seahorses or allow the spread of disease.

We noted that there is not enough baseline information about the seahorses in Ting Kok East
Relocation Site or information on density dependent responses of seahorses to be confident that new arrivals from Lung Mei Project Site will generate no competition.

We added that, conversely, the arrival of new seahorses might enhance mate opportunities for seahorses from Ting Kok East Relocation Site.

We explored possible impacts of the remedial action on seahorses elsewhere in Greater Lung
Mei.
49

Table 3. Possible impacts of mitigation activities on seahorses at the Lung Mei Project Site, Ting Kok East Relocation Site and
Greater Lung Mei. In this evaluation, we assume no monitoring prior to relocation (but see 3.4.3). We then provide our level of concern about each impact for the individual animals involved. Our evaluations are based on the facts provided to us in the EIA.
We have identified seven possible negative effects and one possible positive effect of remediation activities, as follows:
Neg 1 – increased stress for individuals, and its consequences
Neg 2 – separation of breeding pairs
Neg 3 – direct mortality (e.g. through predation)
Neg 4 – aggression and/or increased competition with other seahorses
Neg 5 – increased disease transmission
Neg 6 – decrease in mate availability
Neg 7 – failure to thrive
Pos 1 – increased mate availability
Possible impacts of mitigation activities on individual seahorses, assuming no monitoring prior to relocation (but see 3.4.4)
Immediate Lung Mei Project Site Ting Kok East Relocation Greater Lung Level of
Capture
Handling
Tagging
Transport
Release
Seahorse interactions
Neg 1, Neg 2
Neg 1
Neg 1
Neg 1
Neg 1, Neg 3
Neg 4, Neg 5, Pos 1
Site
Not Applicable
Not Applicable
Neg 1
Not Applicable
Not Applicable
Neg 4, Neg 5, Pos 1
Mei
Neg 2
Not Applicable
Not Applicable
Not Applicable
Not Applicable
Neg 6
Concern
Low
Low
Low
Low
Low
Low
Delayed
All relocation procedures
Seahorse
Interactions
Future
Monitoring
Neg 1, Neg 3, Neg 7
Neg 2, Neg 4, Neg 5, Pos 1
Neg 1
Not Applicable
Neg 2, Neg 4, Neg 5, Pos 1
Neg 1
Not Applicable
Neg 6
Neg 1
Moderate
Low
Low
3.4. ENHANCEMENTS FOR ERM’S PROPOSED PRECAUTIONARY MITIGATION
MEASURES
In this section, we make suggestions that should enhance ERM’s Proposed Precautionary Mitigation
Measures[8]. We try to follow ERM’s outline of procedures with additional sections on seahorse monitoring and stress.
3.4.1. Setting the goal and objectives for mitigation process
We consider it vital that the CEDD sets a single clear goal (with multiple objectives) for its mitigation work with seahorses in Lung Mei Project Site, against which it can measure its success or effectiveness.
In its documentation, CEDD alludes only briefly to two aims: “promote proliferation and sustainability of seahorses” [referring to those from Lung Mei] 3 [1] and “to promote the survivorship of the relocated
3 Agreement No. PW 1/2013 Development of a Bathing Beach at Lung Mei, Tai Po Investigation and
Design of Precautionary Mitigation Measures for Seahorses – Final Inception Report. P.5
50

seahorses” 4
[1]. Both statements were with reference to specific activities for enhancing with artificial habitat and not just for relocation per se
. ERM mentions in passing one aim as being to “reduce the potential impacts to seahorses found within the Lung Mei Project Site” 5 [8].
We suggest that specific objectives might include the following among many others, with the decision resting with CEDD:

80% of seahorses from Lung Mei Project Site survive relocation (for a defined period).

60% of seahorses from Lung Mei Project Site establish residence in Ting Kok East Relocation
Site.

40% of seahorses from Lung Mei Project Site reproduce three times after relocation.

The number of seahorses in Ting Kok East Relocation Site remains stable (if the hope is merely to avoid adverse impacts of the relocation).

The number of seahorses in Ting Kok East Relocation Site increases, at least partly as a result of relocation.
These and many more objectives would be reasonable but it is important to define the anticipated success in order to guide mitigation measures more carefully.
3.4.2. Target seahorse species
The proposed remediation plan needs to consider all Hippocampus species that may be present in the area (see 1.3.3). At present, it mentions only H. kuda as the target species for relocation but other seahorses should also be incorporated: H. trimaculatus is known from this region of Hong Kong and H. spinosissimus is inferred to be present in Hong Kong waters. Our advice would be the same for any species – to follow ERM’s plan tempered by our input – but assessment and relocation would clearly need to treat each species separately, particularly in the matter of reception sites and populations.
3.4.3. Monitoring before relocation in Lung Mei Project Site and Ting Kok East Relocation Site
We encourage CEDD to consider monitoring seahorses in Lung Mei Project Site, Ting Kok East
Relocation Site and Greater Lung Mei for as many months as possible before any relocation takes place; such preparation would help to plan the relocation and to provide baseline metrics for any assessment of effectiveness (see 3.4.1). Ideally the animals should be measured and marked individually[140] during this monitoring, to allow baseline data and preparation for the relocation (see 3.4.5). Such preparation would also reduce stress for many animals during the actual relocation.
For each sighting, the following should be recorded (see Section 2.2.1.3, 3.4.4, 3.4.5, and 3.4.6):
4 Agreement No. PW 1/2013 Development of a Bathing Beach at Lung Mei, Tai Po Investigation and
Design of Precautionary Mitigation Measures for Seahorses – Final Inception Report. P.6
5 Development of a Bathing Beach at Lung Mei, Tai Po Investigation and Design of Precautionary
Mitigation Measures for Seahorses- Precautionary Mitigation Measures Report. P.10
51


Species

Sex

Reproductive Status

Torso length to nearest 0.5 cm ( Figure 7 ; [132])

Tag identity

Sighting location, depth and holdfast

Proximity to nearest seahorses

Signs of stress or injury
Regular tracking should generate the following information:

Species identification and presence

Seahorse abundance

Size structure

Sex ratio

Population estimates, through mark/recapture study (if the animals are marked or tagged)

Seasonal fluctuations and changes

Reproductive cycle and outputs

Habitat preferences

Putative pairs, remembering that seahorses in Lung Mei Project Site may have partners elsewhere in Greater Lung Mei.
All new information – especially about seasonal fluctuations in numbers or reproduction – will be highly useful for minimizing impacts from construction activities on seahorse populations. For example, identifying putative pairs (two animals of the opposite sex that interact repeatedly) in Lung Mei Project
Site will allow the mates to be moved and placed together during the relocation. As another example, an understanding of precisely where resident seahorses from Ting Kok East Relocation Site are situated (by sex and pair status) could help in appropriate placing for the newcomers from Lung Mei Project Site.
Furthermore, if it is discovered that H. Kuda in the Lung Mei Project Site do participate in seasonal migrations, it would be possible to plan the timing of threatening aspects of construction (e.g. sand filling) around this behavior.
3.4.4. Capture and measurement methods
We here provide a method for seahorse capture and measurement, to fill gaps in ERM documentation.
This process must be carefully implemented for these unusual fish.
To extract the seahorse from its holdfast, the field biologist should unhook tickle the tip of its tail until it releases its grasp[143]. The field biologist then places the seahorses into a hard plastic container and takes it to the surface[143].
Once the seahorse is onboard (or ashore), the information in 3.4.4 should be recorded, with torso length being directly measured as follows:
52

 The biologist holds the seahorse in one hand with its tail curled around the biologist’s little finger
(temporary holdfast)[143].
 The biologist holds the seahorse’s trunk between thumb and forefinger and measures its torso length with a caliper held in the other hand, while the seahorse lies passively[143].
Further information on how to assess seahorses can be found in Project Seahorse’s toolkit for monitoring seahorse populations underwater [132].
3.4.5. Tagging the seahorses
We recommend tagging the seahorses from both Lung Mei Project Site and Ting Kok East Relocation
Site (see 3.4.2). This procedure should only be undertaken by a Fish Expert trained in Visible Implant
Florescent Elastomers (VIFE) techniques with seahorses.
All seahorses should be tagged with VIFE once measurements have been taken. VIFE is a two-part polymer, which trained biologists mix and apply using a 0.3 cc injecting syringe with a 29 gage narrow bore hypodermic needle[144]. Once animals are captured by hand, the VIFE should be injected under the skin on the lateral surfaces of the tail and abdomen[144]. The VIFE is injected as a liquid and subsequently hardens under the seahorse skin[144]. The amount of liquid dispensed for tagging is less than 0.05 cc. The VIFE covers less than 1% over the subcutaneous area of the skin. Both laboratory and field tests have verified that these tags do not cause damage or mortality[144]. This tagging methodology allows monitors to track individual seahorses for months and years[144]. It is readily applied after some initial coaching.
We recommend that biologists mark seahorses individually to generate useful information and flexibility for analysis at no extra cost or trouble. The best approach is to use one colour on each of three trunk rings to create a series of distinctive combinations[144].
3.4.6. Search and capture methods for eventual relocation
For the actual relocation, seahorses should ideally be captured in a non-breeding season, at a time when many animals may be unpaired[145]. Breeding season in Lung Mei Project Site is unknown at present but could be inferred from the monitoring (noting presence of pregnant males) conducted before relocation. On the day of relocation, it would be best to collect seahorses early in the day to maximize the chances that members of a pair are found near each other.
Given that it will be very important to find all the seahorses in Lung Mei Project Site and Ting Kok East
Relocation Site before relocating the former, we recommend the following:

That the silt curtain be set up at Lung Mei Project Site before conducting any searches for seahorses in the area. This will prevent seahorses outside the area from entering, while confining all the seahorses likely to be affected by the Project to within the search area.

That searching is done by a team of people who cover as much area as possible, on multiple days, until saturation is reached (when additional seahorse sightings per unit search effort
53

reaches zero). We do not understand the basis for ERM’s recommendation of ≥28 hours of searching (or 46 hours if pregnant males are found).

That seahorses be found through systematic but wide ranging swims. Transects are not effective for finding sparsely distributed animals, particularly for the highly cryptic seahorses. Moreover, this is not a survey but a relocation experiment.
It should be noted that finding seahorses is a slow business, requiring careful 360° inspection of possible holdfasts in search of the animal’s head, trunk or (more easily) tail. This should be done on scuba in even the shallowest waters.
All seahorses that are captured should be measured and evaluated as outlined in 3.4.3 and 3.4.4, and newly discovered individuals should be marked with VIFE as outlined in 3.4.5.
3.4.7. Transport to relocation site
We make the following additions to ERM’s suggested protocol, while emphasising the ERM guideline that seahorses should be transported and released on the same day of capture.

Only seahorses in good health should be transported[146].

Seahorses should not be sedated for transport[46].

Individuals of different species should not be transported in the same bag or container unless species are known to be compatible with one another[46].
The following protocol is extracted from the Syngnathid Husbandry in Public Aquariums Manual on transporting seahorses internationally, and suggests many precautions[46]. Seahorses have been successfully transported long distances using Kordon Breathable bags http://www.petsforum.com/novalek/kordonp.htm. No oxygen is added to these bags, and the top of the bag is tied off at the surface of the water. Seahorses transported this way do not get sloshed out of the water in transit not do they accidentally ingest air from snapping at the water line. For most species, the use of holdfasts in the bag is also recommended. It allows these fish that naturally spend a lot of time holding onto something a place to rest and conserve energy to reduce their metabolism during transport.
Types of holdfasts that have been used include thin twisted pieces of PVC rod and small plastic plants.
Bags should be placed in sturdier containers, ensuring they do not touch one another. If the box is too large, newspaper or empty inflated bags should be used to ensure the bags do not move within the container during transport. Containers should be secured to the boat, truck etc. to avoid any possible movement and should be maintained in a horizontal position at all times[146]. Heat / cool packs can be used should the transit conditions dictate. Fishes that have become sick or that have been injured during transport should receive veterinary treatment as soon as possible and, if necessary, should be humanely destroyed[146]. A record of any such occurrences should be kept[146]. Sick or dead fishes should be removed from containers, when feasible, and a record kept[146].
While we recognize that CEDD will be able to choose simpler measures for transporting seahorses the
<500 m from Lung Mei Project Site to Ting Kok East Relocation Site, this account of international transport is still informative. It supports our view that, contrary to ERM’s guidelines, there is no need to change the water every hour nor to provide oxygen. The former would be disruptive, possibly adding
54

stress[46]. And the latter could be problematic, given how easily seahorses contract gas bubble/buoyancy diseases [46]. We do note, however, that there may be value in providing shade or cover for containers, placing holdfasts in the container, and placing at least two seahorses together in a container; our observations suggest that the presence of another seahorse reduces stress[94].
3.4.8. Release at Ting Kok East Relocation Site
While the ERM protocol recommends that seahorses be released into the habitat type and depth at which they are found, there is no recommendation relating to the spatial distribution of seahorse releases in
Ting Kok East Relocation Site. We make the following suggestions to maximize the chance of survival for the animals relocated from Lung Mei Project Site.

Plan the releases carefully, freeing only two seahorses at a time (as a pair if known)[147]. This gradual release should reduce the risk from predation. It would probably be best to allow an hour between releases, to let the previously-released animals settle[147].

Scatter the seahorses, in putative pairs. Seahorses of most species (and especially the males) occupy fairly small home ranges. It would be best not to pile them on top of each other at release, or on top of the members of the relocation population[147]. This may also reduce predation risk.

Monitor the released seahorses underwater at a few meters distance until they settle onto holdfasts, where they are safer from currents and predation. This may take some time but it will be better to wait than to interfere.
3.4.9. Monitoring after relocation
We recommend a revision to ERM’s monitoring plan to improve capacity to evaluate the success of the relocation. Regular monitoring will improve understanding of how well the seahorses as both Lung Mei
Project Site and Ting Kok East Relocation Site respond to the relocation. It may also help reveal whether any seahorse disappearances – which are entirely possible – are likely a result of further movement or mortalities.

Ting Kok East Relocation Site should be surveyed daily for the first week following relocation procedures, three times a week until the end of the first month, weekly for three months, then monthly for a year.

Lung Mei Project Site and Greater Lung Mei should be surveyed weekly for the first month after relocation, then monthly for the next year to evaluate impacts from the Project on seahorses in these areas. Particular effort should be paid to searching the shark net installed at Lung Mei
Project Site as it may act as new habitat and attract seahorses to the area.
We provide a sample monitoring sheet for the surveys (see Appendix 3). Data recording should cover the same variables as in 3.4.4.
55

3.4.10. Special considerations for seahorses in sensitive conditions
Three categories of seahorse – those that are actively courting/mating, pregnant or injured – need special comment.

In the unlikely event that courting pairs are encountered during the relocation exercise, it would be best to defer collection until late in the day – most seahorses court in the morning – and to make special efforts to identify release partners together and monitor their later behaviour.

Pregnant seahorses should just be moved along with the others with particular care taken to ensure they settle to a holdfast on release.

Seahorses that are already injured on discovery should also just be moved along with the others.
Wild seahorses have been known to survive loss of tail sections or severe pouch injuries, with later breeding success.

In the unlikely event that a seahorse is injured in transit, it is probably still best to release and monitor it. Shore-based treatment and holding would add stress to the animal and seahorse veterinary medicine is still rudimentary.
3.4.11. Identifying signs of seahorse stress
We here contribute comments on seahorse stress, an area not included in the ERM report. Seahorses exhibit stress in a number of ways[96, 97].
 gaping (head tilts upwards, mouth opens, no sound produced)
 clicking (head tilts upwards, mouth opens, and clicking sound produced)
3
.
 increased breathing
 tail adjustments
 extended moving or swimming (without grasping holdfast)
 females drop eggs before or during transfer to mate
 pregnant males expel pre-mature embryos [148]
Such behavioral changes in response to environmental stress could lead to suppressed immune function and disease resistance, growth rate and reproduction[96, 97, 148].
It would be good practice for the fish expert to monitor seahorses for indicators of stress every 30-60 minutes during the relocation. It would also be useful to record concerns on the monitoring sheets so they can be considered when reviewing the success of the relocation (once the goal is articulated).
Realistically, however, it is difficult to see how such monitoring for stress would affect the relocation, once it is underway. The key will be to do everything possible ab initio to reduce stress, particularly by placing a holdfast in the transport containers and providing some shade or cover for the container.
3.5. CONCLUSION FOR PHASE 3
Our best understanding is that this Project is unlikely to threaten wild populations of H. kuda .
Moreover, most impacts from the Project raise little concern even for individual seahorses, although we
56

deduce that noise levels across the region and habitat damage in Lung Mei Project Site may cause problems for particular animals in Lung Mei Project Site, Ting Kok East Relocation Site and Greater
Lung Mei. Already planned remediation will reduce many possible impacts. The big remaining risk, however, is that the relocated animals will fail to thrive in Ting Kok East Relocation Site and either die or leave.
We have provided a large amount of information about possible seahorse reaction to the Project and to proposed mitigation efforts, as a complement to the substantive report already provided by ERM. We recognize that CEDD will have to make choices in its implementation of our advice. At a minimum, we urge CEDD to monitor seahorses in both Lung Mei Project Site and Ting Kok East Relocation Site for months before and after the relocation. The installation of a shark net will add an interesting angle on the Project, given the general tendency for seahorses to cling to such structures. We also urge CEDD to monitor noise in Lung Mei Project Site and Ting Kok East Relocation Site throughout the Project as this is the most likely irritant for the seahorses; results from this Project could help improve future remedial efforts. The planned water quality monitoring will also offer useful information when evaluating the
Project. We note and endorse the plans to erect a silt screen around Lung Mei Project Site.
The most important omission at present is a clear statement of the goal and objectives of remedial action for seahorses, and then a set of metrics against which the Project will be evaluated. Once that is articulated, CEDD has the potential to undertake a globally important case study of seahorse relocations.
Such an initiative will be important for the persistence of individual seahorses from Lung Mei Project
Site but could also become internationally useful as other relocation projects are mooted, especially given the increasing focus on seahorse conservation under the CITES Appendix II listing for all species.
57

APPENDIX 1 – Seahorse species found in Southeast Asia
Maximum height in cm, preferred habitat and confirmed distribution are reported. All information taken from Lourie et al 2004 [10 ] , except where indicated.
SPECIES
H. barbouri
H. bargibanti
H. comes
H. denise
H. histrix
SIZE
(CM)
REPORTED
HABITATS
15
2.4
18.7
2.14
17
Seagrass, hard corals
Gorgonian corals
Coral reef, sponge, kelp,
Sargassum,
Gorgonian seafans
REPORTED
DEPTH
RANGE
To 10 m
16 to 40 m
To 20 m
13 to 102 m[150, 151]
Seagrass, weedy rocky reefs, sponges, soft bottom with soft corals and sponges
6 to 20 m
CONFIRMED
DISTRIBUTION
SUSPECTED
DISTRIBUTION
Indonesia, Malaysia, Philippines No other locations suspected
Australia, New Caledonia, Federated States of
Indonesia, Japan, Papua New
Guinea, Philippines
China[149], Indonesia,
Micronesia, Malaysia,
Palau, Solomon
Islands, Vanuatu
No other locations suspected Malaysia, Philippines,
Singapore, Thailand, Vietnam
Australia[151], Indonesia,
Malaysia, Federated States of
Micronesia, Palau, Papua New
Guinea, Philippines, Solomon
Islands, Vanuatu
China, Federated States of
No other locations suspected
Micronesia, New Caledonia,
Reunion, Tahiti, India,
Indonesia, Japan, Malaysia,
Mauritius, Papua New Guinea,
Philippines, Samoa, South
Africa, Tonga, United Republic of Tanzania, Hawaii, Vietnam
Bangladesh; Brunei
Darussalam;
Cambodia; China
( Hong Kong SAR and Province of
Taiwan); Comoros;
Fiji; Kenya; Kiribati;
Madagascar;
Mozambique;
Myanmar; Nauru;
Palau; Seychelles;
Singapore; Solomon
Islands; Sri Lanka;
Thailand; Tuvalu;
United
States of America
(American Samoa);
Vanuatu
58

SPECIES
H. kelloggi
H. kuda
H. mohnikei
H. spinosissimus
SIZE
(CM)
28
17
8
17.2
H. trimaculatus 17
REPORTED
HABITATS
Gorgonian corals, sea whips, soft bottoms
Coastal bays and lagoons, seagrass, sandy sediments in rocky littoral zone, macroalgae, seagrass beds, muddy bottoms, mangroves, estuaries, harbours, lower reaches of rivers
Seagrass, estuaries
Octocorals, macro algae, sand, near coral reefs
Octocorals, macro algae, gravel, sandy bottoms near shallow reefs, muddy bottoms
REPORTED
DEPTH
RANGE
To 152 m[152]
To 8 m (but maximum reported depth of 55 m)[152]
Shallow waters
(2 to 6 m)[94,
128, 153]
>8 m to 70 m[158]
3 m[94] to 100 m[159]
CONFIRMED
DISTRIBUTION
China, India, Indonesia, Japan,
Malaysia, Pakistan, Philippines,
Thailand, United Republic of
Tanzania, Vietnam
Australia, Cambodia, China
( Hong Kong SAR & Taiwan),
Fiji, New Caledonia, Tahiti,
India, Indonesia, Japan,
Malaysia, Pakistan, Papua New
Guinea, Philippines, Federated
States of Micronesia, Singapore;
Solomon Islands, Thailand;
Tonga; Hawaii, Vietnam
Cambodia[154], India[153],
Japan, Korea[155],
Malaysia[94], Thailand [156, 157] ,
Vietnam[47]
Australia, Cambodia, China,
Indonesia, Malaysia, Myanmar,
Philippines, Singapore,
India[159], Thailand, Vietnam
Australia, Cambodia, China
( Hong Kong SAR & Taiwan),
Tahiti, India, Indonesia, Japan,
Malaysia, Myanmar,
Philippines, Singapore,
Thailand, Vietnam
SUSPECTED
DISTRIBUTION
Australia; Bahrain;
Bangladesh; Brunei
Darussalam;
Cambodia;
China (Hong Kong
SAR and Province of
Taiwan); Djibouti;
Egypt; Eritrea; Iraq;
Islamic Republic of
Iran; Israel; Kenya;
Kuwait; Myanmar;
Oman; Qatar; Saudi
Arabia;
Seychelles;
Singapore; Somalia;
Sri Lanka;
Sudan; United Arab
Emirates; Yemen
Bangladesh; Brunei
Darussalam; China;
Kiribati; Myanmar;
Nauru; Palau; Samoa;
Sri Lanka; Tuvalu;
United States of
America (American
Samoa); Vanuatu
Cambodia; China;
Thailand; Viet Nam
Bangladesh; Brunei
Darussalam; China;
China ( Hong Kong
SAR ); India; Papua
New Guinea
Bangladesh; Brunei
Darussalam; China;
Papua New Guinea;
Sri Lanka
59

SPECIES
H. pontohi
H. satomiae
H. severnsi
H. waleananus
SIZE
(CM)
1.4
1.1
1.3
1.6
REPORTED
HABITATS
Algae, soft corals, hydroids
Seafans, coral reef
Bryozoans, hydrozoans, gorgonians, macro algae
Soft coral
REPORTED
DEPTH
CONFIRMED
DISTRIBUTION
RANGE
11 to 25 m[160] Indonesia
5 to 26 m[160,
161]
Brunei, Indonesia, Malaysia
8 to 20 m[160] Indonesia, Japan,
Papua New Guinea, Solomon
Islands, Fiji
5 to 20 m [162] Indonesia
SUSPECTED
DISTRIBUTION
No other locations suspected
No other locations suspected
No other locations suspected
No other locations suspected
60

APPENDIX 2 - Sygnathid growth rate estimates
Reproduced from Morgan and Vincent 2013 [43]. Estimates of growth rates from other syngnathids extracted from published literature, from FishBase or modified from Takahashi et al
2003. T = temperature in degrees Celsius; in situ/ex situ defines whether parameters were obtained from wild or captive populations, respectively, NG = not given in reference. Mean ± 1 s.d. brood sizes are given where available; asterisk denotes a peak in the proportion of males pregnant:not pregnant, months are given as 1 = Jan ….12 = Dec; K = growth coefficient; Linf = mean asymptotic (maximum) size.
61

APPENDIX 3 – Sample monitoring sheets for seahorse surveys
62

63

1.
2.
3.
4.
5.
6.
7.
ERM, Development of a Bathing Beach at Lung Mei, Tai Po Investigation and Design of
Precautionary and Mitigation Measures for Seahorses - Final Inception Report.
2013a.
Barlow, G.W., Patterns of monogamy among teleost fishes.
Archiv fur Fischereiwissenschaft,
1984. 35 (1): p. 75-123.
ERM, Development of a Bathing Beach at Lung Mei, Tai Po Environmental, Drainage and
Traffic Impact Assessments – Investigation Environmental Impact Assessment Report.
2007. 1 .
ERM, Additional Information in Response to EPD's Letter Ref. (92) in EP2/N5/C/46. Pt.4.
2008.
ERM, Development of a Bathing Beach at Lung Mei, Tai Po Further Investigation and Design of
Marine Ecological Mitigation Measures - Final Marine Ecology Investigation Report.
2013e.
ERM, Development of a Bathing Beach at Lung Mei, Tai Po Investigation and Design of
Precautionary Mitigation Measures for Seahorses - Seahorse Review Report.
2013c.
ERM, Development of a Bathing Beach at Lung Mei, Tai Po Investigation and Design
Precautionary Mitigation Measures for Seahorses - Seahorse Investigation Report.
2013b.
ERM, Development of a Bathing Beach at Lung Mei, Tai Po Investigation and Design of 8.
9.
Precautionary Mitigation Measures for Seahorses - Precautionary Mitigation Measures Report.
2013d.
Foster, S.J. and A.C.J. Vincent, Life history and ecology of seahorses: implications for conservation and management.
Journal of Fish Biology, 2004. 64 (6): p. 1-61.
10. Lourie, S.A., et al., A Guide to the Identification of Seahorses . 2004, Washington D.C.:
University of British Columbia and World Wildlife Fund.
11. Lourie, S.A., A.C.J. Vincent, and H.J. Hall, Seahorses: An identification guide to the world's species and their conservation . 1 ed. 1999, London, UK: Project Seahorse. 224.
12. Lourie, S.A., Pers. Comm .
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