Parks Victoria Technical Series No 28
Victorian Subtidal Reef Monitoring
Program:
The Reef Biota in the Port Phillip Bay
Marine Sanctuaries
Malcolm Lindsay
Matt Edmunds
Australian Marine Ecology Pty Ltd
February 2006
Parks Victoria Technical Series No. 28
PPB Sanctuaries Subtidal Reef Monitoring
EXECUTIVE SUMMARY
Shallow reef habitats cover extensive areas along the Victorian coast and are dominated by
seaweeds, mobile invertebrates and fishes. These reefs are known for their high biological
complexity, species diversity and productivity. They also have significant economic value
through commercial and recreational fishing, diving and other tourism activities. To effectively
manage and conserve these important and biologically rich habitats, the Victorian
Government has established a long-term Subtidal Reef Monitoring Program (SRMP). Over
time the SRMP will provide information on the status of Victorian reef flora and fauna and
determine the nature and magnitude of trends in species populations and species diversity
through time.
The subtidal reef monitoring program is established throughout Victoria for all relevant
marine protected areas. This study involved the third (2005) survey of the Northern Port
Phillip Bay sites associated with the Point Cooke, Jawbone and Ricketts Point Marine
Sanctuaries.
The subtidal reef monitoring program uses standardised underwater visual census methods
to survey algae, macroinvertebrates and fish. For northern Port Phillip Bay, the sites are in
shallow water between 2 and 4 m deep. This report aims to:
•
•
•
Provide general descriptions of the biological communities and species populations at
each monitoring site in April 2005;
Identify any unusual biological phenomena such as interesting or unique communities or
species; and
Identify any introduced species at the monitoring locations.
The surveys were done along a 200 m transect line. Each transect was surveyed for:
1. Abundance and size structure of large fishes;
2. Abundance of cryptic fishes and benthic invertebrates;
3. Percentage cover of macroalgae; and
4. Density of dominant kelp species.
The macroalgae at the northern Port Phillip Bay sites was generally sparse compared to the
coastal regions, reflecting the sheltered bay to estuarine environmental conditions. Most of
the coverage was by a mixture of carpeting green Caulerpa species, including Caulerpa
flexilis, C. brownii, C. geminata, C. longifolia and C. remotifolia. Caulerpa was most abundant
at the Point Cooke and Ricketts Point regions, along with a sparse mixture of small brown
and red algal species. Other predominant species were encrusting coralline algae, common
kelp Ecklonia radiata and sea lettuce Ulva sp. The algae at Jawbone Marine Sanctuary
consisted predominantly of filamentous brown algae, characteristic of estuarine
environments with freshwater and nutrient inputs nearby. Some temporal changes were
apparent between surveys, however the relative similarities and differences between sites
remained the same between the three surveys.
The invertebrate fauna at all sites was dominated by the common sea urchin Heliocidaris
erthrogramma, blacklip abalone Haliotis rubra and seastars. The seastars Patiriella calcar, P.
brevispina, Tosia australis, Uniophora granifera and Coscinasterias muricata were prevalent
in the Point Cooke and Jawbone regions. The most abundant seastars in the Ricketts Point
region was Tosia australis, Petricia vernicina and Coscinasterias muricata. Some minor
changes in species abundances were observed between surveys, however the general
assemblage structure of each site remained the same.
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PPB Sanctuaries Subtidal Reef Monitoring
The fish fauna was generally sparse in northern Port Phillip Bay, having low species richness
and low abundances of most species. The fauna at all locations was dominated by the
southern hulafish Trachinops caudimaculatus, with abundances of this species varying
substantially between sites and times. This made it difficult to detect any patterns in the
structure of fish assemblages in each of the marine sanctuary regions with such a short time
series.
Results from the three monitoring surveys describe the reef community structure for a brief
snapshot in time. Reef communities are dynamic over short, medium and long time scales.
As monitoring continues and longer-term datasets are accumulated (over multiple years to
decades) the program will be able to more adequately reflect trends and changes in
community or population structure as well as to identify specific ecological patterns occurring
in these ecosystems.
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Parks Victoria Technical Series No. 28
PPB Sanctuaries Subtidal Reef Monitoring
CONTENTS
EXECUTIVE SUMMARY............................................................................................. I
CONTENTS...............................................................................................................
III
INDEX OF FIGURES AND TABLES.......................................................................... V
1. INTRODUCTION ..................................................................................................1
1.1 Subtidal Reef Ecosystems Of Northern Port Phillip Bay ................................................ 1
1.2 Subtidal Reef Monitoring Program ................................................................................. 4
1.2.1 Objectives .................................................................................................................................4
1.2.2 Monitoring Protocols and Locations ..........................................................................................6
1.2.3 Monitoring in Port Phillip Bay Marine Sanctuaries .....................................................................6
2. METHODS............................................................................................................7
2.1 Site Selection and Survey Times ................................................................................... 7
2.2 Census Method ............................................................................................................. 8
2.2.1 Transect Layout ........................................................................................................................8
2.2.2 Method 1 – Mobile Fishes and Cephalopods............................................................................9
2.2.3 Method 2 – Invertebrates and Cryptic Fishes ...........................................................................9
2.2.4 Method 3 – Macroalgae and Sessile Invertebrates ...................................................................9
2.2.5 Method 4 – Macrocystis .........................................................................................................10
2.3 Data Analysis .............................................................................................................. 11
2.3.1 Community Structure ..............................................................................................................11
2.3.2 Depiction of Community Differences .......................................................................................11
2.3.3 Trends in Community Structure. .............................................................................................12
2.3.4 Species Diversity ....................................................................................................................12
2.3.5 Species Populations ...............................................................................................................12
3. REGIONAL ANALYSIS......................................................................................14
3.1 Biogeography ............................................................................................................... 14
3.2 Macroalgae ................................................................................................................. 14
3.3 Invertebrates ................................................................................................................ 17
3.4 Fishes .......................................................................................................................... 19
4. POINT COOKE MARINE SANCTUARY ............................................................21
4.1 Monitoring Sites ........................................................................................................... 21
4.2 Macroalgae ................................................................................................................. 21
4.4 Invertebrates ............................................................................................................... 23
4.5 Fishes ......................................................................................................................... 26
5. JAWBONE MARINE SANCTUARY ...................................................................28
5. JAWBONE MARINE SANCTUARY ...................................................................28
5.1 Monitoring Sites .......................................................................................................... 28
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5.2 Macroalgae .................................................................................................................... 28
5.3 Invertebrates ................................................................................................................ 30
5.4 Fishes ........................................................................................................................... 33
6. RICKETTS POINT MARINE SANCTUARY .........................................................35
6.1 Monitoring Sites ............................................................................................................ 35
6.2 Macroalgae .................................................................................................................... 35
6.3 Invertebrates ................................................................................................................ 37
6.4 Fishes ........................................................................................................................... 39
7. REFERENCES ....................................................................................................41
8. ACKNOWLEDGEMENTS ...................................................................................42
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INDEX OF FIGURES AND TABLES
FIGURES
Figure 1.1. Examples of species of invertebrates found on subtidal reefs in northern Port
Phillip Bay ...................................................................................................................... 3
Figure 1.2. Examples of macroalgae found on subtidal reefs in northern Port Phillip Bay. ...... 4
Figure 1.3. Examples of fish species found on subtidal reefs in northern Port Phillip Bay. ...... 4
Figure 1.4 An example plot depicting change in an environmental, population or community
variable over time (days, months or years). The black circles denote examples of
monitoring times. ........................................................................................................... 5
Figure 2.1. Location of monitoring sites in northern Port Phillip Bay. Marine Sanctuaries are
indicated in yellow.......................................................................................................... 7
Figure 2.2. Biologist-diver with transect reel. ...................................................................... 13
Figure 2.3. The cover of macrophytes is measured by the number of points intersecting each
species on the quadrat grid. ......................................................................................... 13
Figure 3.1. MDS plot of algal assemblage structure in northern Port Phillip Bay. Sites are
labelled next to the point representing the first survey at each site. Stress = 0.09. ....... 15
Figure 3.2. Trends in algal species richness. ....................................................................... 16
Figure 3.3. Trends in algal species diversity. ....................................................................... 16
Figure 3.4. MDS plot of invertebrate assemblage structure in northern Port Phillip Bay. Sites
are labelled next to the point representing the first survey at each site. Stress = 0.09. 17
Figure 3.5. Trends in invertebrate species richness. ............................................................ 18
Figure 3.6. Trends in invertebrate species diversity. ............................................................ 18
Figure 3.7. MDS plot of fishes assemblage structure in northern Port Phillip Bay. Sites are
labelled next to the point representing the first survey at each site. Stress = 0.09. ....... 19
Figure 3.8. Trends in fish species richness. ......................................................................... 20
Figure 3.9. Trends in fish species diversity. ......................................................................... 20
Figure 4.1. Abundances of selected macroalgal species in the Point Cooke region. ............ 22
Figure 4.2. Abundances of selected invertebrates in the vicinity of Point Cooke Marine
Sanctuary. ................................................................................................................... 24
Figure 4.3. Abundances of selected invertebrate species in the vicinity of Point Cooke Marine
Sanctuary. ................................................................................................................... 25
Figure 4.4. Mean sizes (± 95% confidence intervals) of black lip abalone Haliotis rubra at
Point Cooke Marine Sanctuary and RAAF Base reference site .................................... 26
Figure 4.5. Abundances of southern hulafish Trachinops caudimaculatus and little rock
whiting Neoodax balteatus in the vicinity of Point Cooke Marine Sanctuary. ................ 27
Figure 5.1. Abundances of selected macroalgal species in the vicinity of Jawbone Marine
Sanctuary. ................................................................................................................... 29
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Figure 5.2 Abundances of selected invertebrate species in the vicinity of Jawbone Marine
Sanctuary. .................................................................................................................. 31
Figure 5.3 Abundances of selected invertebrate species in the vicinity of Jawbone Marine
Sanctuary. .................................................................................................................. 32
Figure 5.4. Mean sizes (± 95% confidence intervals) of black lip abalone Haliotis rubra at
Jawbone Marine Sanctuary and Point Gellibrand reference site. ................................. 33
Figure 5.5. Abundances of southern hulafish Trachinops caudimaculatus and little rock
whiting Neoodax balteatus in the vicinity of Point Cooke Marine Sanctuary. ................ 34
Figure 6.1. Abundances of selected macroalgal species in the vicinity of Ricketts Point
Marine Sanctuary. ....................................................................................................... 36
Figure 6.2 Abundances of selected invertebrate species in the vicinity of Ricketts Point
Marine Sanctuary. ....................................................................................................... 38
Figure 6.3. Mean sizes (± 95% confidence intervals) of black lip abalone Haliotis rubra at
Ricketts Point Marine Sanctuary and Halfmoon Bay reference site. ............................. 39
Figure 6.4. Abundances of southern hulafish Trachinops caudimaculatus and little rock
whiting Neoodax balteatus in the vicinity of Ricketts Point Marine Sanctuary. .............. 40
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TABLES
Table 2.1. Subtidal reef monitoring sites in northern Port Phillip Bay ..................................... 8
Table 2.2. Mobile fish surveyed in northern Port Phillip Bay using Method 1......................... 9
Table 2.3 Invertebrates and cryptic fish surveyed in northern Port Phillip Bay using Method 2.
......................................................................................................................................
10
Table 2.4 Macroalgae surveyed in northern Port Phillip Bay using Method 3. ...................... 10
VII
Parks Victoria Technical Series No. 28
PPB Sanctuaries Subtidal Reef Monitoring
1. INTRODUCTION
1.1 Subtidal Reef Ecosystems Of Northern Port Phillip Bay
Rocky reefs in Port Phillip Bay are generally restricted to the near-shore regions of
headlands and points. Reefs in the northwest of the bay, along the Geelong Arm, are
predominantly near Point Lilias, Point Wilson and Kirks Point. These reefs occur in short
coastal strips from the intertidal zone to 2-4 m depth, bounded by bare sediment and
seagrass habitats a short distance form shore (10s of metres). Occasional small patches of
reef, 10-50 m across, are present further offshore, particularly between Point Wilson and
Kirks Point. These patch reefs are mostly 1-3 m deep.
Along the northern shore of the bay, small patches of shallow reef, interspersed by silty
sands, are also present in the vicinity of Point Cooke, western beach (north of Point Cooke),
Altona, Jawbone (Williamstown Rifle Range), Point Gellibrand and Point Ormond. These
reefs are generally no deeper than 4 m. More extensive reef habitat is present from
Sandringham to Ricketts Point, extending from the shore 50-100 m and to a depth of
approximately 6 m.
In general the reefs in the northern half of the bay are quite sheltered from the prevailing
northwesterly to southwesterly weather and are not subject to large waves, strong currents or
swell. One exception is Ricketts Point which can be subject to steep, short-period waves
during southwesterly storms. These reefs are in estuarine conditions and are subject to lower
salinities from coastal runoff, rivers and drains, as well as considerable temperature ranges
(as low as 8° C in winter and as high as 23° C in summer). The northern reefs are also
frequently subject to turbid conditions from phytoplankton blooms and disturbance of
adjacent, moderate to fine sediments.
Reefs on the northeastern side of the bay, particularly between Halfmoon Bay and Ricketts
Point, are exposed to the prevailing westerly weather across a relatively long fetch of water.
Consequently, these reefs are occasionally subject to turbulent wind-driven waves. These
northeastern reefs are also influenced, to some extent, by the Yarra River plume and eastcoast drainages.
Reef habitats in the north of Port Phillip Bay are different from the predominant reef habitats
in Victoria, which occur on exposed open coasts. While there are similar species inhabiting
both sheltered reefs in the north of the bay and reefs on more exposed coasts, there are
substantial and important differences in community structure between the two reef
environments. Seaweeds are the predominant biological habitat providers in both locations
however the importance of large canopy forming species such as crayweed Phyllospora
comosa and common kelp Ecklonia radiata is much reduced on reefs in the bay. Smaller
species of brown algae (10 – 30 cm high) such as Sargassum spp. and Dictyota dichotoma
and green algae, particularly in the genus Caulerpa, are often the dominant habitat providers
on reefs in the bay (Figure 1.1). Species of Caulerpa can form large, mixed-species
assemblages creating meadow-like habitat in some locations. Grazed algal turfs and hard
encrusting layers of coralline algae are also important species growing directly over the rocky
substratum.
Grazing and predatory mobile invertebrates are prominent animal inhabitants of the reef
(Figure 1.2). Large grazing species such as the urchin Heliocidaris erythrogramma and
blacklip abalone Haliotis rubra can occur in very high densities and are enormously
productive components of the bay’s reef communities. These species can significantly
influence the growth and survival of habitat forming algal species and so are important
structuring components of reef communities. Filter feeding species feed on phytoplankton
and detritus and can be important for transferring nutrients and energy from the water
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column to other species directly inhabiting reefs. Filter feeding species on reefs in the north
of the bay include aggregations of mussels Mytilus edulis planulatus, ascidians such as
Herdmania momus and the introduced European fanworm Sabella spallanzanii. Other filter
feeders are colonial species including sponges, bryozoans and soft corals such as
Erythropodium hicksoni. Important predatory invertebrates include octopus such as Octopus
berrima and seastars including Coscinasterias muricata and Uniophora granifera. Predatory
gastropod molluscs (shellfish) include the dogwhelk Dicathais orbita and Pleuroploca
australasia.
Fish are usually dominant components of reef ecosystems both in terms of biomass and
ecological function. Reef fish assemblages include predators such as snapper Crysophrys
auratus, omnivores including zebrafish Girella zebra, planktivores such as the southern
hulafish Trachinops caudimaculatus and picker-feeders such as horseshoe leatherjacket
Meuschenia hippocrepis. Schools of small baitfish, particularly herrings, sardines, pilchards
and sprats are common over reef habitats in the north of the bay. Reefs also provide
important habitat and source of food for juveniles of many fish species including snapper
Crysophrys auratus on reefs in the north and east of the bay. Many fish species play a
substantial ecological role in the functioning and structuring of reef ecosystems. Reef fish
assemblages in the north of Port Phillip Bay are different to those in exposed coastal which
tend to have higher abundances of wrasses (labrids), cales (odacids) and leatherjackets
(monocanthids).
Although shallow reef ecosystems in Victoria are dominated, in terms of biomass and
production, by seaweeds, mobile invertebrates and fishes, there are many other important
biological components to the reef ecosystem. These include small species of crustaceans
and molluscs from 0.1 to 10 mm in size (mesoinvertebrates), occupying various niches as
grazers, predators and detritovores. At the microscopic level, films of microalgae and
bacteria on the reef surface are also important.
Victoria’s shallow reefs are a very important component of the marine environment because
of their high biological complexity, species diversity and productivity. Subtidal reef habitats
have important social and cultural values, which incorporate aesthetic, recreational,
commercial and historical aspects. Shallow subtidal reefs also have significant economic
value, through commercial fishing of reef species such as abalone and sea urchins, as well
as recreational fishing, diving and other tourism activities. Reefs in the north of Port Phillip
Bay are highly accessible components of the marine environment because of their proximity
to the large population centres of Melbourne and surrounding suburbs. Consequently, these
reefs are subject to pressures due to human activities.
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PPB Sanctuaries Subtidal Reef Monitoring
Sea urchin Heliocidaris erythrogramma
Blacklip abalone Haliotis rubra
Eleven armed seastar Coscinasterias muricata
Seastar Uniophora granifera
Biscuit star Tosia australis with filamentous
Stony coral Plesiastrea versipora
green and brown algae
Figure 1.1. Examples of species of invertebrates found on subtidal reefs in northern Port Phillip Bay.
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Green algae Caulerpa brownii
Species of thallose red algae with green algae
Caulerpa brownii, Caulerpa trifaria and Cladophora prolifera.
Figure 1.2. Examples of macroalgae found on subtidal reefs in northern Port Phillip Bay
Southern hulafish Trachinops caudimaculatus
Globefish Diodon nichthemerus
Figure 1.3. Examples of fish species found on subtidal reefs in northern Port Phillip Bay.
1.2 Subtidal Reef Monitoring Program
1.2.1 Objectives
An important aspect of the management and conservation of Victorian marine natural
resources and assets is assessing the condition of the ecosystem and how this changes over
time. Combined with an understanding of ecosystem processes, this information is important
to manage any threats or pressures on the environment to ensure ecosystem sustainability.
Consequently, the Victorian Government has established a long-term Subtidal Reef
Monitoring Program (SRMP). The primary objective of the SRMP is to provide information on
the status of Victorian reef flora and fauna (focussing on macroalgae, macroinvertebrates
and fish). This includes monitoring the nature and magnitude of trends in species
abundances, species diversity and community structure. This is achieved through regular
surveys at locations throughout Victoria, encompassing both representative and unique
habitats and communities.
Information from the SRMP allows managers to better understand and interpret long-term
changes in the population and community dynamics of Victoria’s reef flora and fauna. As a
longer time series of data is collected, the SRMP will allow managers to:
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PPB Sanctuaries Subtidal Reef Monitoring
•
compare changes in the status of species populations and biological communities
between highly protected marine national parks and marine sanctuaries and other
Victorian reef areas (e.g. Edgar and Barrett 1997, 1999);
•
determine associations between species and between species and environmental
parameters (e.g. depth, exposure, reef topography) and assess how these associations
vary through space and time (e.g. Edgar et al. 1997; Dayton et al. 1998; Edmunds, Roob
& Ferns 2000);
•
provide benchmarks for assessing the effectiveness of management actions, in
accordance with international best practice for quality environmental management
systems (Holling 1978; Meredith 1997); and
determine the responses of species and communities to unforeseen and unpredictable
events such as marine pest invasions, mass mortality events, oil spills, severe storm
events and climate change (e.g. Ebeling et al. 1985; Edgar 1998; Roob et al. 2000;
Sweatman et al. 2003).
•
Parameter
A monitoring survey gives an estimate of population abundance and community structure at
a small window in time. Patterns seen in data from periodic surveys are unlikely to exactly
match changes in the real populations over time or definitively predict the size and nature of
future variation. Plots of changes over time are unlikely to match the changes in real
populations because changes over shorter time periods and actual minima and maxima may
not be adequately sampled (Figure 1.4). Furthermore, because the nature and magnitude of
environmental variation is different over different time scales, variation over long periods may
not be adequately predicted from shorter-term data. Sources of environmental variation can
operate at the scale of months (e.g. seasonal variation), years (e.g. el Niño), decades (e.g.
extreme storm events) or even centuries (e.g. global warming). Other studies indicate this
monitoring program will begin to adequately reflect average trends and patterns as the
surveys continue over longer periods (multiple years to decades). Results always need to be
interpreted within the context of the time scale over which they have been measure
Time
Figure 1.4 An example plot depicting change in an environmental, population or community variable
over time (days, months or years). The black circles denote examples of monitoring times. Note how
data from these times may not necessarily reflect patterns over shorter time periods, or true maxima or
minima over longer time periods. Note further how data from any window of 2 or 3 consecutive
monitoring times fails to adequately estimate the patterns or variation over the longer time period.
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1.2.2 Monitoring Protocols and Locations
The SRMP uses standardised underwater visual census methods based on an approach
developed and applied in Tasmania by Edgar and Barrett (1997). Details of standard
operational procedures and quality control protocols for Victoria’s SRMP are described in
Edmunds and Hart (2003).
The SRMP was initiated in May 1998 with 15 sites established on subtidal reef habitats in the
vicinity of Port Phillip Heads Marine National Park. In 1999 the SRMP was expanded to reefs
in the vicinity of the Bunurong Marine National Park, Phillip Island, and Wilsons Promontory
Marine National Park.
In 2003 and 2004, the Subtidal Reef Monitoring Program was expanded to include Marine
National Parks and Marine Sanctuaries throughout Victoria.
1.2.3 Monitoring in Port Phillip Bay Marine Sanctuaries
This report describes the subtidal reef monitoring program and the results of the first two
surveys of reefs in northern Port Phillip Bay, incorporating marine sanctuaries at Point
Cooke, Jawbone and Ricketts Point. The objectives of this report were to:
1. Provide an overview of the methods used for the SRMP;
2. Provide general descriptions of the biological communities and species populations at
each monitoring site in April 2004 and to describe changes that have occurred since the
first monitoring survey in 2003;
3. Identify any unusual biological phenomena such as interesting or unique communities or
species; and
4. Identify any introduced species at the monitoring locations.
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2. METHODS
2.1 Site Selection and Survey Times
Six paired monitoring sites were established on northern Port Phillip Bay subtidal reefs in
March-April 2003 (Figure 2.1; Table 2.1). One monitoring site was located within, and one
site was located outside, each marine sanctuary. All monitoring sites were located on
representative subtidal reef habitat in each location.
The second survey of the established monitoring sites on northern Port Phillip Bay reefs was
in April 2004, while the third survey occurred April 2005.
Six paired monitoring sites were established on northern Port Phillip Bay subtidal reefs in
March-April 2003 (Figure 2.1; Table 2.1). One monitoring site was located within, and one
site was located outside, each marine sanctuary. Sanctuary monitoring sites were located on
representative subtidal reef habitat within each marine sanctuary, with reference sites
located on similar habitat nearby. A description of the monitoring sites is given in the
following sections for each marine sanctuary. Data from reference monitoring sites will allow
analysis and interpretation of trends or changes in species composition and community
structure within the marine sanctuaries.
Melbourne
5810000
Willia mstown
3
4
MGA Northing (m)
5805000
Point Coo k
5800000
RAAF Base
1
2
Halfmoon Bay
6
5795000
Ricketts Point
Port Phillip Bay
5
5790000
5785000
300000
30 5000
310000
315000
320000
325 000
330000
MGA Easting (m)
Figure 2.1. Location of monitoring sites in northern Port Phillip Bay. Marine Sanctuaries are indicated
in yellow.
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Table 2.1. Subtidal reef monitoring sites in northern Port Phillip Bay
Site No.
Site Name
Sanctuary/Reference
Depth (m)
Point Cooke Marine Sanctuary
4101
Point Cooke
Sanctuary
3
4102
RAAF Base
Reference
4
Jawbone Marine Sanctuary
4103
Jawbone
Sanctuary
3
4104
Point Gellibrand
Reference
2
Ricketts Point
4105
Ricketts Point
Sanctuary
3
4106
Halfmoon Bay
Reference
3
2.2 Census Method
2.2.1 Transect Layout
The visual census methods of Edgar and Barrett (Edgar and Barrett 1997, 1999; Edgar et al.
1997) are used for this monitoring program as they are non-destructive and provide
quantitative data on a large number of species, and the structure of the reef communities.
The Edgar-Barrett method is also used in Tasmania, New South Wales and Western
Australia. The adoption of this method in Victoria provides a systematic and comparable
approach to monitoring reefs in southern Australia. The surveys in Victoria are in accordance
with a standard operational procedure to ensure long-term integrity and quality of the data
(Edmunds and Hart 2003).
At most monitoring locations in Victoria, surveying along the 5 m depth contour is considered
optimal because diving times are not limited by decompression schedules and these reefs
are of interest to natural resource managers. However, the actual depth that can be surveyed
varies with reef extent, geomorphology and exposure. Monitoring sites along the western
coast of Victoria are between 3 and 8 m deep.
Each site is located using differential GPS and marked with a buoy or the boat anchor. A
100 m numbered and weighted transect line is run along the appropriate depth contour either
side of the central marker. The resulting 200 m of line is divided into four contiguous 50 m
sections (T1 to T4). The orientation of transect is the same for each survey, with T1 generally
toward the north or east (i.e. anticlockwise along the coast).
For each transect, three different census methods were used to obtain adequate descriptive
information on reef communities at different spatial scales. These involved the census of: (1)
the abundance and size structure of large fishes; (2) the abundance of cryptic fishes and
benthic invertebrates; and (3) the percent cover of macroalgae and sessile invertebrates.
Over 100 species were observed during the monitoring program along the western coast of
Victoria (Tables 2.2 - 2.4). The depth, horizontal visibility, sea state and cloud cover are
recorded for each site. Horizontal visibility is gauged by the distance along the transect line
to detect a 100 mm long fish. All field observations are recorded on underwater paper.
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2.2.2 Method 1 – Mobile Fishes and Cephalopods
The densities of mobile large fishes and cephalopods are estimated by a diver swimming up
one side of a 50 m section of the transect, and then back along the other. The diver records
the number and estimated size-class of fish, within 5 m of each side of the line. The sizeclasses for fish are 25, 50, 75, 100, 125, 150, 200, 250, 300, 350, 375, 400, 500, 625, 750,
875 and 1000+ mm. Each diver has size-marks on their underwater slate to enable
calibration of their size estimates. A total of four 10 x 50 m sections of the 200m transect are
censused for mobile fish at each site. The data for easily sexed species are recorded
separately for males and female/juveniles. Such species include the blue-throated wrasse
Notolabrus tetricus, herring cale Odax cyanomelas, barber perch Caesioperca rasor, rosy
wrasse Pseudolabrus psittaculus and some leatherjackets.
Table 2.2. Mobile fish surveyed in northern Port Phillip Bay using Method 1.
Method 1
Trygonorrhina fasciata
Pempheris multiradiata
Nesogobius sp.
Atherinid sp.
Girella zebra
Acanthaluteres vittiger
Neosebastes scorpaenoides
Scorpis aequipinnis
Meuschenia flavolineata
Platycephalus bassensis
Tilodon sexfasciatus
Meuschenia freycineti
Caesioperca rasor
Enoplosus armatus
Meuschenia hippocrepis
Trachinops caudimaculatus
Parma victoriae
Aracana ornata
Arripis trutta
Cheilodactylus nigripes
Tetractenos glaber
Chrysophrys auratus
Dactylophora nigricans
Diodon nichthemerus
Upeneichthys vlaminghii
Neoodax balteatus
2.2.3 Method 2 – Invertebrates and Cryptic Fishes
Cryptic fishes and megafaunal invertebrates (non-sessile: e.g. large molluscs, echinoderms,
crustaceans) are counted along the transect lines used for the fish survey. A diver counts
animals within 1 m of one side of the line (a total of four 1 x 50 m sections of the 200 m
transect). A pole carried by the diver is used to standardise the 1 m distance. The maximum
length of abalone is measured in situ using vernier callipers whenever possible. Selected
specimens are collected for identification and preservation in a reference collection.
2.2.4 Method 3 – Macroalgae and Sessile Invertebrates
The area covered by macroalgal and sessile invertebrate species is quantified by placing a
0.25 m2 quadrat at 10 m intervals along the transect line and determining the percent cover
of the all plant species. The quadrat is divided into a grid of 7 x 7 perpendicular wires, giving
50 points (including one corner). Cover is estimated by counting the number of times each
species occurs directly under the 50 positions on the quadrat (1.25 m2 for each of the 50 m
sections of the transect line). Selected specimens are collected for identification and
preservation in a reference collection.
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2.2.5 Method 4 – Macrocystis
In addition to macroalgal cover, the density of Macrocystis angustifolia plants is estimated.
While swimming along the 200 m transect line, a diver counts all observable plants within
5 m either side of the line, for each 10 m section of the transect (giving counts for 100 m2
sections of the transect).
Table 2.3 Invertebrates and cryptic fish surveyed in northern Port Phillip Bay using Method 2.
Method 2
Mollusca
Echinodermata
Polychaeta
Plagusia chabrus
Tosia australis
Sabella spallanzani
Haliotis rubra
Tosia magnifica
Diodora lineata
Petricia vernicina
Cryptic Fish
Dicathais orbita
Patiriella exigua
Aetapcus maculatus
Pleuroploca australasia
Patiriella calcar
Vincentia conspersa
Ceratosoma brevicaudatum
Patiriella brevispina
Pempheris multiradiata
Ostrea angasi
Coscinasterias muricata
Bovichtus angustifrons
Asterias amurensis
Parablennius tasmanianus
Crustacea
Uniophora granifera
Norfolkia clarkei
Strigopagurus strigimanus
Amblypneustes sp.
Heteroclinus perspicillatus
Pagurid unidentified
Heliocidaris erythrogramma
Nesogobius sp.
Nectocarcinus tuberculatus
Brachaluteres jacksonianus
Table 2.4 Macroalgae surveyed in northern Port Phillip Bay using Method 3.
Method 3
Chlorophyta (green)
Phaeophyta (brown)
Rhodophyta (red algae)
Ulva spp
Leathesia difformis
Haliptilon roseum
Cladophora prolifera
Splachnidium rugosum
Encrusting corallines
Cladophora spp
Dictyota dichotoma
Gigartina sp.
Caulerpa remotifolia
Dilophus marginatus
Callophyllis rangiferina
Caulerpa longifolia
Lobospira bicuspidata
Plocamium angustum
Caulerpa brownii
Distromium flabellatum
Dictymenia harveyana
Caulerpa flexilis
Zonaria turneriana
Laurencia filiformis
Caulerpa geminata
Colpomenia peregrina
Laurencia tumida
Caulerpa simpliciuscula
Ecklonia radiata
Codium spp
Caulocystis cephalornithos
Sessile Invertebrates
Filamentous greens
Acrocarpia paniculata
Other sponges
Cystophora moniliformis
Plesiastrea versipora
Cystophora retroflexa
Amathia sp.
Cystophora subfarcinata
Unidentified colonial ascidian
Sargassum linearifolium
Erythropodium hicksonii
Sargassum spinuligerum
Sargassum spp
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2.3 Data Analysis
To identify changes and trends within marine protected areas, sites from inside each MPA
will be compared to paired reference sites outside each MPA. For the first survey, data from
all sites is compared together. This allows an assessment of biota at each site to be placed
in a bioregional context. Descriptions of the biota and community structure at each site are
also provided.
2.3.1 Community Structure
Community structure is a function of both the species present and the abundance of each
species. The community structure between pairs of samples was compared using the BrayCurtis dissimilarity coefficient. This index compares the abundance of each species between
two samples to give a single value of the difference between the samples, expressed as a
percentage (Faith et al. 1987; Clarke 1993).
Prior to analysis, the data were log transformed to weight down the influence of highly
abundant species in describing community structure, giving a more even weighting between
abundant and rarer species (following abundance transformations by Sweatman et al. 2000).
The Bray-Curtis dissimilarity index was calculated for all possible combinations of sites. This
resulted in a matrix of pair-wise comparisons known as a dissimilarity matrix. The
dissimilarity matrix is also termed a distance matrix as it effectively represents distances
between samples in hyper-dimensional space. The dissimilarity matrix was used for all
analyses of community structure in this study.
2.3.2 Depiction of Community Differences
The hyper-dimensional information in the dissimilarity matrix was simplified and depicted
using non-metric multidimensional scaling (MDS; Clarke 1993). This ordination method finds
the representation in fewer dimensions that best depicts the actual patterns in the hyperdimensional data (i.e. reduces the number of dimensions while depicting the salient
relationships between the samples). The MDS results were then depicted graphically to show
differences between the replicates at each location. The distance between points on the MDS
plot is representative of the relative difference in community structure.
Kruskall stress is an indicator statistic calculated during the ordination process and indicates
the degree of disparity between the reduced dimensional data set and the original hyperdimensional data set. A guide to interpreting the Kruskall stress indicator is given by Clarke
(1993): (< 0.1) a good ordination with no real risk of drawing false inferences; (< 0.2) can
lead to a usable picture, although for values at the upper end of this range there is potential
to mislead; and (> 0.2) likely to yield plots which can be dangerous to interpret. These
guidelines are simplistic and increasing stress is correlated with increasing numbers of
samples. Where high stress was encountered with a two-dimensional data set, threedimensional solutions were sought to ensure an adequate representation of the higherdimensional patterns.
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2.3.3 Trends in Community Structure
Trends in community structure will be examined quantitatively when further surveys have
been completed at each location.
2.3.4 Species Diversity
Species diversity involves the consideration of two components: species richness and
evenness. Species richness is the number of species present in the community while
evenness is the degree of similarity of abundances between species. If all species in a
community have similar abundances, then the community has a high degree of evenness. If
a community has most of the individuals belonging to one species, it has low evenness.
Species diversity is a combination of species richness and the relative abundance of each
species, and is often referred to as species heterogeneity. Measures of diversity give an
indication of the likelihood that two individuals selected at random from a community are
different species.
Species richness (S) was enumerated by the total species count per site. This value was
used for calculation of evenness and heterogeneity statistics. Species diversity (i.e.
heterogeneity among species) was described using the reciprocal of Simpson’s index
(1/DSimpson = Hill’s N2). This value describes species diversity as a combination of species
richness (i.e. the number of species) and species evenness (i.e. the equitability of the
abundances of the species). The value varies between 1 and s (i.e. the total number of
species in the sample) with higher values indicating higher diversity. In general, Hills N2
gives an indication of the number of dominant species within a community. Hills N2 provides
more weighting for common species, in contrast to indices such as the Shannon-Weiner
Index (Krebs 1999), which weights the rarer species. The weighting of common species was
considered more appropriate for this study because the sampling regime is designed to
target the more common species.
2.3.5 Species Populations
The abundance of each species was summarised by calculating total counts of fish and
invertebrates and total percentage cover of macroalgae, for each site. Specific analyses of
trends in species abundances over time will be examined when additional monitoring surveys
have been completed. Except for small species (e.g. Trachinops caudimaculatus), fish
abundances were generally low at sites in northern Port Phillip Bay. This meant the
assessment of population size structures of fishes was not appropriate for this region. The
population size structure for blacklip abalone Haliotis rubra was assessed by calculating
mean lengths and size frequency curves.
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Figure 2.2. Biologist-diver with transect reel.
Figure 2.3. The cover of macrophytes is measured by the number of points intersecting each species
on the quadrat grid.
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3. REGIONAL ANALYSIS
3.1 Biogeography
Victoria’s marine environment has been classified into five bioregions. These bioregions
reflect differences in physical processes such as ocean currents and geology, which in turn
influence the distribution of ecosystems and diversity over scales of 100-1000 km. Point
Cooke, Jawbone and Ricketts Point Marine Sanctuaries are in the Victorian Embayments
bioregion, which includes Port Phillip Bay, Westernport Bay and Corner Inlet.
The reef habitats in the northern half of the bay are quite sheltered from the prevailing
northwesterly to southwesterly weather and are not subject to large waves, strong currents or
swell. However, these reefs are in estuarine conditions and are subject to lower salinities
from coastal runoff, rivers and drains (35-31 PSU), as well as considerable temperature
ranges (as low as 8° C in winter and as high as 23° C in summer). The northern reefs are
also frequently subject to turbid conditions, from phytoplankton blooms, coastal discharges
and disturbance of nearby fine sediments.
Reefs on the northeastern side of the bay, particularly between Halfmoon Bay and Ricketts
Point, are exposed to the prevailing westerly weather across a relatively long fetch of water.
Consequently, these reefs are occasionally subject to turbulent wind-driven waves. These
northeastern reefs are also influenced, to some extent, by the Yarra River plume and eastcoast drainages.
These environmental differences are reflected in the floral and faunal assemblages, with the
subtidal reef biota of northern Port Phillip Bay being quite different to those of the coastal
Central Victoria bioregion reefs (Edmunds et al. 2003a and 2003b). Analyses of the Parks
Victoria monitoring data for the indicated the principal differences between these bioregions
were:
• A lack of kelps and other large seaweeds on the northern reefs, having a higher
predominance of smaller algae such as Caulerpa species, Dictyota dichotoma and Ulva
sp;
•
•
Higher abundances in the north of the sea urchin Heliocidaris erythrogramma, seastars
Patiriella brevispina, P. calcar and Coscinasteria muricata and the featherworm Sabella
spallanzanii – the Heads region having higher abundances of the crinoid Cenolia
trichoptera, warrener (periwinkle) Turbo undulatus, greenlip abalone Haliotis laevigata
and seastars of the Nectria genus; and
Higher abundances of hulafish Trachinops caudimaculatus, moonlighter Tilodon
sexfasciatus and salmon Arripis sp in the north with a predominance of labrids (wrasses),
Odax spp (cales) and monacanthids (leatherjackets) in the Heads region (Edmunds et al.
2003a and 2003b).
3.2 Macroalgae
Within the north of the bay, the two most northern sites Jawbone and Point Gellibrand were
the most different from the northwestern (Point Cooke) and northeastern (Ricketts Point)
regions of the Bay (Figure 3.1). This was largely because of the absence of the carpeting
green Caulerpa algae and a predominance of filamentous brown turfs at the northern sites.
Temporal changes in assemblage structure appeared to be greater in the Point Cooke and
Jawbone region, especially at Point Gellibrand (Site 4). This was largely because the total
abundances of algae are low in these sites so minor abundance changes have a relatively
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greater effect on the overall community structure. In general, the relative differences between
areas in northern Port Phillip Bay were maintained between 2003 and 2005 (Figure 3.1).
The species richness and diversity of algal assemblages in the Ricketts Point region was
generally higher than elsewhere in Port Phillip Bay, with Point Cooke and Jawbone sites
having the lowest species richness and slightly lower diversity (Figures 3.2 and 3.3).
S2
S1
S6
S5
S4
S3
Figure 3.1. MDS plot of algal assemblage structure in northern Port Phillip Bay. Sites are labelled next
to the point representing the first survey at each site. Stress = 0.09.
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Point Cooke MS
Jawbone MS
30
30
30
Species Count
Site 1
Sanctuary
Sites
Site 3
20
20
10
10
10
0
0
0
30
30
Site 2
Species Count
Site 5
20
30
Reference
Sites
Ricketts Point MS
Site 4
Site 6
20
20
20
10
10
10
0
2003
2004
2005
0
2006 2003
2004
Year
2005
0
2006 2003
2004
Year
2005
2006
Year
Figure 3.2. Trends in algal species richness.
Point Cooke MS
Jawbone MS
15
15
Site 1
Site 3
10
10
10
5
5
5
0
0
0
15
15
15
Site 2
Site 4
Site 6
10
10
10
5
5
5
Hills N2
Reference
Sites
Site 5
Hills N2
Sanctuary
Sites
Ricketts Point MS
15
0
2003
2004
2005
0
2006 2003
2004
Year
2005
Year
Figure 3.3. Trends in algal species diversity.
16
0
2006 2003
2004
2005
Year
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3.3 Invertebrates
Within the north of the bay, the invertebrate assemblages were different between the
northwest (Point Cooke), northern (Jawbone) and northeastern (Ricketts Point) regions of the
Bay (Figure 3.4). The main differences between these regions were largely because of
variations in the abundance of blacklip abalone Haliotis rubra, common sea urchin
Heliocidaris erythrogramma and seastars Patiriella calcar and P. brevispina.
Although slight differences in invertebrate assemblage structure was apparent between
years, the relative differences between regions and sites was maintained (Figure 3.4).
The species richness of the invertebrate assemblages were similar between sites and
regions in northern Port Phillip Bay, although a higher species richness was observed at
Point Cooke during the first survey (Figure 3.5). The diversity at most sites was relatively low
because of a dominance of only two species: Heliocidaris erythrogramma and Haliotis rubra
(Figure 3.6). The invertebrate species diversity was slightly higher at Point Cooke and
Jawbone.
S1
S2
S3
S4
S5
S6
Figure 3.4. MDS plot of invertebrate assemblage structure in northern Port Phillip Bay. Sites are
labelled next to the point representing the first survey at each site. Stress = 0.09.
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Point Cooke MS
30
Jawbone MS
30
30
Species Count
Site 1
Sanctuary
Sites
Site 3
20
20
10
10
10
0
0
0
30
30
Site 2
Species Count
Site 5
20
30
Reference
Sites
Ricketts Point MS
Site 4
Site 6
20
20
20
10
10
10
0
2003
2004
2005
0
2006 2003
2004
Year
2005
0
2006 2003
2004
Year
2005
2006
Year
Figure 3.5. Trends in invertebrate species richness.
Point Cooke MS
10
Jawbone MS
10
Hills N2
Site 1
Sanctuary
Sites
Site 3
Hills N2
Site 5
8
8
8
6
6
6
4
4
4
2
2
2
0
0
0
10
10
10
Site 2
Reference
Sites
Ricketts Point MS
10
Site 4
Site 6
8
8
8
6
6
6
4
4
4
2
2
2
0
2003
0
2004
2005
0
2006 2003
2004
Year
2005
Year
Figure 3.6. Trends in invertebrate species diversity.
18
2006 2003
2004
2005
Year
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3.4 Fishes
Most species were very low in density, apart from one or two species in high abundances
that dominated the community structure. The southern hulafish Trachinops caudimaculatus
was the most dominant species, but was highly variable in abundances between times within
sites, making it difficult to make regional comparisons in assemblage structure. The high
variability in the dominant Trachinops cuadimaculatus contributes to the high variation of all
sites through time, in particular Point Cooke and Point Gellibrand (Site 1 and 4; Figure 3.7).
The species richness was relatively higher at the northeastern Bay sites (Ricketts Point
region) with the lowest numbers of species at the northern sites (Jawbone region; Figure
3.8). The dominance in number of Trachinops caudimaculatus was reflected in the diversity
statistics, with all sites having low fish species diversity (Figure 3.9). However, in the last
survey higher species diversity was recorded at both sites in the Point Cooke region, in
particular at the RAAF Base (Site 2).
S3
S1
S5
S4
S6
S2
Figure 3.7. MDS plot of fishes assemblage structure in northern Port Phillip Bay. Sites are labelled
next to the point representing the first survey at each site. Stress = 0.09.
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Point Cooke MS
30
Jawbone MS
30
30
Species Count
Site 1
Sanctuary
Sites
Site 3
20
20
10
10
10
0
0
0
30
30
Site 2
Species Count
Site 5
20
30
Reference
Sites
Ricketts Point MS
Site 4
Site 6
20
20
20
10
10
10
0
2003
2004
0
2006 2003
2005
2004
Year
2005
0
2006 2003
2004
Year
2005
2006
Year
Figure 3.8. Trends in fish species richness.
Point Cooke MS
Jawbone MS
10
10
10
Hills N2
Site 1
Sanctuary
Sites
Site 3
8
8
6
6
6
4
4
4
2
2
2
0
0
0
10
10
Site 2
Hills N2
Site 5
8
10
Reference
Sites
Ricketts Point MS
Site 4
Site 6
8
8
8
6
6
6
4
4
4
2
2
2
0
2003
2004
2005
0
2006 2003
2004
Year
2005
Year
Figure 3.9. Trends in fish species diversity.
20
0
2006 2003
2004
2005
Year
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4. POINT COOKE MARINE SANCTUARY
4.1 Monitoring Sites
Point Cooke Marine Sanctuary is close to Werribee on the northwestern shore of the bay.
The subtidal reef at Point Cooke consists of low-relief, textured basalt reef interspersed with
patches of sand and mud. The Point Cooke monitoring site (Site 4101) was positioned along
the 3-4 m depth contour over the reef and patches of sand.
A reference monitoring site was located offshore from the RAAF Base at Laverton (RAAF
Base; Site 4102), approximately 3 km southwest of Point Cooke Marine Sanctuary. The reef
at RAAF Base is similar to Point Cooke. It consists mostly of low-relief reef but with less
extensive patches of sand and mud. The RAAF Base monitoring site is at 3-4 m depth.
4.2 Macroalgae
The reef at Point Cooke (Site 4101) was patchy and interspersed with large areas of bare
sediment. This was reflected in the patchy distribution and cover of algae at this site. The
dominant species was common kelp Ecklonia radiata, but this occurred in low abundance.
Smaller species in low abundance during the first survey, but much higher in abundance
during the second survey included the green algae Ulva sp. and Caulerpa remotifolia. Other
species present included brown algae Dilophus marginatus and Dictyota dichotoma and
thallose red algae such as Gigartina sp.
The RAAF Base (Site 4102) was predominantly a Caulerpa bed assemblage dominated by
Caulerpa flexilis, but also included C. longifolia, C. brownii, C. remotifolia, and C.
simpliciuscula. Ecklonia radiata and patches of encrusting corallines were also present at this
site. In general, there was a higher total cover of algae at RAAF Base than at Point Cooke.
Changes in species cover were observed between the three surveys. The green carpeting
alga Caulerpa remotifolia increased its cover at Point Cooke, and at RAAF Base (Figure 4.1).
There was also an apparent decline in the cover of the common kelp Ecklonia radiata at the
RAAF Base and the cover of pink encrusting coralline at both sites (Figure 4.1).
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Point Cooke MS
RAAF Base
Percent Cover
Ecklonia radiata
30
30
20
20
10
10
0
0
Percent Cover
Encrusting corallines
30
30
20
20
10
10
0
0
Percent Cover
Caulerpa remotifolia
30
30
20
20
10
10
0
0
Percent Cover
Ulva sp.
30
30
20
20
10
10
0
2003
0
2004
2005
2006
2003
Year
2004
2005
Year
Figure 4.1. Abundances of selected macroalgal species in the Point Cooke region.
22
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4.4 Invertebrates
The invertebrate assemblages at Point Cooke and RAAF Base were dominated by
echinoderms, with similar species at both sites. Heliocidaris erythrogramma was highly
abundant, with generally 320 individuals per 200 m2 at Point Cooke and 800-1000 per 200
m2 at RAAF Base. The seastars Patiriella brevispina, Coscinasterias muricata, Uniophora
granifera and Tosia australis were abundant at these sites. Tosia australis, Pateriella
brevispina and Coscinasterias muricata were the predominant assemblage components. The
seastar Patiriella calcar was present in moderate abundances at Point Cooke (70-90 per 200
m2), but was not observed at the RAAF Base site. The blacklip abalone Haliotis rubra was
highly abundant at each site, with 330-380 individuals per 200 m2 at Point Cooke and 100210 per 200 m2 at RAAF Base (Figure 4.2).
Between the three surveys, there was a relatively large decrease in the abundance of
blacklip abalone H. rubra, the sea urchin Heliocidaris erythrogramma and the seastar Tosia
australis (Figure 4.2). Other species showed little change or high variability between the
three survey periods (Figures 4.2 and 4.3).
The mean size of blacklip abalone Haliotis rubra ranged between 84 and 91 mm. There were
no marked differences between sites and times in the vicinity of the Point Cooke Marine
Sanctuary (Figure 4.4). Smaller individuals were more frequent at RAAF Base during the first
survey.
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Point Cooke MS
RAAF Base
Abundance
Haliotis rubra
500
500
400
400
300
300
200
200
100
100
0
0
Heliocidaris erythrogramma
1200
800
800
400
400
0
0
Abundance
1200
Abundance
Patiriella brevispina
110
110
88
88
66
66
44
44
22
22
0
0
Abundance
Tosia australis
60
60
40
40
20
20
0
2003
2004
2005
0
2003
2006
Year
2004
2005
2006
Year
Figure 4.2. Abundances of selected invertebrates in the vicinity of Point Cooke Marine Sanctuary.
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Point Cooke MS
RAAF Base
Abundance
Coscinasterias muricata
50
50
40
40
30
30
20
20
10
10
0
0
Abundance
Uniophora granifera
50
50
40
40
30
30
20
20
10
10
0
0
Abundance
Petricia vernicina
30
30
20
20
10
10
0
2003
2004
2005
0
2003
2006
Year
2004
2005
2006
Year
Figure 4.3. Abundances of selected invertebrate species in the vicinity of Point Cooke Marine
Sanctuary.
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Length (mm)
Pt Cooke
RAAF Base
120
120
110
110
100
100
90
90
80
80
70
70
60
2003
2004
2005
2006
Time
60
2003
2004
2005
2006
Time
Figure 4.4. Mean sizes (± 95% confidence intervals) of black lip abalone Haliotis rubra at Point Cooke
Marine Sanctuary and RAAF Base reference site.
4.5 Fishes
The southern hulafish Trachinops caudimaculatus was one of the most abundant fish
species at Point Cooke and RAAF Base. Other typical species were little rock whiting
Neoodax balteatus, southern goatfish Upeinichthys vlaminghii and small unidentified fishes
(probably post-larval stages). There were occasional sightings of banjo ray Trygonorrhina
fasciata, zebrafish Girella zebra, moonlighter Tilodon sexfasciatus, dusky morwong
Dactylophora nigricans and globefish Diodon nichthemerus.
During the first survey large numbers of the southern hulafish, Trachinops caudimaculatus,
were observed at both sites, however in the subsequent surveys few individuals were seen
(Figure 4.5). There was a low number of little rock whiting Neoodax balteatus observed
during the first survey and higher numbers seen in subsequent surveys (Figure 4.5).
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Point Cooke MS
RAAF Base
Abundance
Trachinops caudimaculatus
250
250
200
200
150
150
100
100
50
50
0
0
Abundance
Neoodax balteatus
50
50
40
40
30
30
20
20
10
10
0
2003
2004
2005
0
2003
2006
Year
2004
2005
2006
Year
Figure 4.5. Abundances of southern hulafish Trachinops caudimaculatus and little rock whiting
Neoodax balteatus in the vicinity of Point Cooke Marine Sanctuary.
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5. JAWBONE MARINE SANCTUARY
5.1 Monitoring Sites
Jawbone Marine Sanctuary is situated between Altona and Williamstown in the north of the
bay. The subtidal reef at Jawbone Marine Sanctuary is in shallow water (< 4 m) and consists
of large basalt boulders sloping steeply to sand at the toe of the reef. The Jawbone
monitoring site (Site 4103) is close to shore and is on the 2-3 m isobath.
A reference monitoring site was located approximately 2 km east of Jawbone Marine
Sanctuary at Point Gellibrand (Site 4104), Williamstown. Reef structure at this site was
similar to the Jawbone reef, consisting predominantly of large basalt boulders, but was
generally flatter with more sand among reef patches. The monitoring site at Point Gellibrand
was at 2 m depth.
5.2 Macroalgae
The algal assemblage at Jawbone Marine Sanctuary (Site 4103) was not very diverse,
consisting predominantly of filamentous brown algae (Ectocarpales), 19-42 % and a low
cover of encrusting coralline algae and occasional plants of Ecklonia radiata, Sargassum spp
and Dictyota dichotoma. Other distinctive reef covering organisms were the coral Plesiastra
versipora and sponges, but these had less than 10 % cover.
The Point Gellibrand (Site 4104) was also characterised by a low abundance of algal
species, the predominant consistent cover being by encrusting coralline algae, with a cover
of approximately 10 %, Ulva with 6-14 % cover and Ecklonia radiata with 2 % cover. Other
species present included sparse coverings of green algae Caulerpa geminata and Codium
sp, the medium-sized brown algae Cystophora moniliformis, Cystophora retroflexa,
Sargassum fallax and Sargassum spinuligerum, filamentous brown algae (Ectocarpales) and
small red algae such as Laurencia spp.
The assemblage structures at Jawbone and Point Gelibrand appear to reflect the stronger
estuarine influence in this region. The lower abundances of larger brown algae and higher
abundances Ectocarpales spp. are an indicator of high nutrient concentrations and lower
salinities.
The sparse, patchy nature of the macroalgae within and near the Jawbone Marine Sanctuary
makes it difficult to intrepret time trends after only three surveys. This will be assessed more
thoroughly as future surveys provide a better picture of temporal and spatial variations in
abundances. Of note was a reduction in the coverage of filamentous brown algal turfs, an
increase in Ecklonia radiata at both sites as well as a decrease in encrusting coralline algal
cover at Point Gellibrand (Figure 5.1).
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Jawbone MS
Point Gellibrand
Percent Cover
Ecklonia radiata
30
30
20
20
10
10
0
0
Percent Cover
Encrusting corallines
18
18
12
12
6
6
0
0
Percent Cover
Filamentous browns
50
50
40
40
30
30
20
20
10
10
0
0
Percent Cover
Ulva sp.
24
24
16
16
8
8
0
2003
2004
2005
0
2003
2006
Year
2004
2005
2006
Year
Figure 5.1. Abundances of selected macroalgal species in the vicinity of Jawbone Marine Sanctuary.
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5.3 Invertebrates
The mobile invertebrate assemblages at Jawbone and Point Gellibrand were composed
largely of the sea urchin Heliocidaris erythrogramma and the seastars Patiriella brevispina,
Patiriella calcar and Coscinasterias muricata. The abundance of H. erythrogramma was
higher at Point Gellibrand, 230-330 compared to 100-150 per 200 m2 at Jawbone.
Abundances of blacklip abalone Haliotis rubra were moderate to low at both sites with 10-40
per 200 m2. The seastars Tosia australis and Uniophora granifera were also common at
these sites (Figure 5.3).
Some species, such as Patiriella calcar, Coscinasterias muricata and Uniophora granifera
appear quite variable through time at both sites (Figures 5.2 and 5.3). Other species, such
as Heliocidaris erythrogramma, Patiriella brevispina and Tosia australis appear to follow a
trend. There was a decreasing trend in Heliocidaris erythrogramma, particularly clear at
Jawbone. Similarly there was also a general decreasing trend in Patiriella brevispina at both
sites (Figure 5.2) and Tosia australis at Jawbone (Figure 5.3). Abundance of Tosia australis
at Point Gellibrand was very similar throughout the 3 surveys (Figure 5.3). However, further
surveys are needed to elucidate any major patterns.
The size structure of the Haliotis rubra was difficult to determine for Jawbone and Point
Gellibrand during the first survey because only a small number of individuals were observed
and measured. During the second survey, abundances were greater and the average length
was 75-83 mm, with more smaller individuals observed at Jawbone. Larger abundances and
mean sizes were recorded during the third survey, with mean lengths of 85 mm for Jawbone
MS and 86 mm for Point Gellibrand (Figure 5.4).
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PPB Sanctuaries Subtidal Reef Monitoring
Jawbone MS
Point Gellibrand
Abundance
Haliotis rubra
50
50
40
40
30
30
20
20
10
10
0
0
Abundance
Heliocidaris erythrogramma
400
400
300
300
200
200
100
100
0
0
Abundance
Patiriella brevispina
90
90
60
60
30
30
0
0
Abundance
Patiriella calcar
120
120
80
80
40
40
0
2003
2004
2005
0
2003
2006
Year
2004
2005
2006
Year
Figure 5.2 Abundances of selected invertebrate species in the vicinity of Jawbone Marine Sanctuary.
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Jawbone MS
Point Gellibrand
Abundance
Coscinasterias muricata
50
50
40
40
30
30
20
20
10
10
0
0
Abundance
Uniophora granifera
21
21
14
14
7
7
0
0
Abundance
Tosia australis
21
21
14
14
7
7
0
2003
2004
2005
0
2003
2006
Year
2004
2005
2006
Year
Figure 5.3 Abundances of selected invertebrate species in the vicinity of Jawbone Marine Sanctuary.
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Length (mm)
Jawbone
Point Gellibrand
120
120
110
110
100
100
90
90
80
80
70
70
60
2003
2004
2005
2006
Time
60
2003
2004
2005
2006
Time
Figure 5.4. Mean sizes (± 95% confidence intervals) of black lip abalone Haliotis rubra at Jawbone
Marine Sanctuary and Point Gellibrand reference site.
5.4 Fishes
At Jawbone and Point Gellibrand, nearly all fish observed were southern hulafish Trachinops
caudimaculatus. Other species, present in very low densities, were zebrafish Girella zebra,
dusky morwong Dactylophora nigricans and little rock whiting Neoodax balteatus. During the
first survey, the density of T. caudimaculatus at Jawbone was exceptionally high, 2200 per
200 m2, with a major decrease observed in the subsequent surveys (Figure 5.5). Neoodax
balteatus was first observed during the second survey. During the third survey lower
numbers were observed at both sites (Figure 5.5).
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Parks Victoria Technical Series No. 28
Abundance
Jawbone MS
PPB Sanctuaries Subtidal Reef Monitoring
Point Gellibrand
Trachinops caudimaculatus
2200
2200
1650
1650
1100
1100
550
550
0
0
Abundance
Neoodax balteatus
15
15
10
10
5
5
0
2003
0
2004
2005
2006
2003
Year
2004
2005
2006
Year
Figure 5.5. Abundances of southern hulafish Trachinops caudimaculatus and little rock whiting
Neoodax balteatus in the vicinity of Point Cooke Marine Sanctuary.
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6. RICKETTS POINT MARINE SANCTUARY
6.1 Monitoring Sites
Ricketts Point Marine Sanctuary is near Beaumaris on the north-eastern shore of the bay.
The reef at Ricketts Point is low relief sandstone reef with occasional steps and crevices,
erosion holes and small rubble fields. The Ricketts Point monitoring site (Site 4105) was at
3 m depth, approximately 70 m offshore from the intertidal rock platform.
A reference monitoring site (Halfmoon Bay; Site 4106) was located approximately 3 km north
of Ricketts Point at Halfmoon Bay. The reef at Halfmoon Bay is low to medium relief (to 1 m)
reef with occasional ledges and overhangs, but also having patches of flat, rubbly reef in
places. This site was at 3 m depth.
The reef habitats at Ricketts Point Marine Sanctuary and Halfmoon Bay have less estuarine
influence than the other northern Port Phillip Bay reefs and are also more exposed to waves
during prevailing westerly and southwesterly weather.
6.2 Macroalgae
Ricketts Point (Site 4105) and Halfmoon Bay (Site 4106) were predominantly Caulerpa bed
assemblages. At Ricketts Point, Caulerpa geminata was the dominant Caulerpa species,
with Ecklonia radiata, Ulva, Cystophora spp, Sargassum spp and encrusting corallines also
being common components of the flora. Most of the substratum cover was by C. geminata
(25 %), E. radiata (1-10 %) and encrusting corallines (5 %). All other algal species were
generally less than 5 % in cover. The stony coral Plesiastrea versipora was also a
predominant of the substratum cover at Ricketts Point.
At Halfmoon Bay, the assemblage was dominated by a mixture of Caulerpa remotifolia (9 %
cover), C. longifolia (3-10 %), C. brownii (9-21 %) and C. geminata (11-27 %), with C.
simpliciuscula also being present (0-8 % Cover). Ecklonia radiata and a variety of small
thallose red algae, such as Laurencia filiformis and Anotrichium spp, were other predominant
components of the assemblage at Halfmoon Bay.
Some species, incuding Ecklonia radiata and Caulerpa remotifolia at Ricketts Point were
variable in abundance over the three surveys (Figure 6.1). The largest changes in
abundances observed between the three surveys were for Caulerpa geminata at both
Ricketts Point and Halfmoon Bay (Figure 6.1). These changes are not considered biologically
significant but will be assessed more closely as more time-series data is collected.
Abundances of Ecklonia radiata and Caulerpa remotifolia at Halfmoon Bay both appeared
relatively constant over the 3 surveys. E.radiata showing a slight increase and C. remotifolia
showing a slight decrease in abundance.
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Ricketts Point
Halfmoon Bay
Percent C over
Eck lonia radiata
30
30
20
20
10
10
0
0
Percent C over
Laurencia filiformis
24
24
16
16
8
8
0
0
Percent C over
Caulerpa remotifolia
24
24
16
16
8
8
0
0
Percent C over
Caulerpa geminata
50
50
40
40
30
30
20
20
10
10
0
2003
2004
2005
0
2003
2006
Year
2004
2005
2006
Year
Figure 6.1. Abundances of selected macroalgal species in the vicinity of Ricketts Point Marine
Sanctuary.
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6.3 Invertebrates
There were relatively few invertebrate species at Ricketts Point and Halfmoon Bay, with the
assemblage structure being similar at both sites. The assemblages were dominated by very
high abundances of the sea urchin H. erythrogramma, with 900-960 per 200 m2 at Ricketts
Point and 480-550 per 200 m2 at Halfmoon Bay. Other predominant species were blacklip
abalone Haliotis rubra, biscuit star Tosia australis, eleven armed seastar Coscinasterias
muricata and velvet star Petricia vernicina.
Fewer common urchins Heliocidaris erythrogramma were observed at both sites during the
third survey, representing a decrease over the three periods (Figure 6.2). Similarly, Tosia
australis showed a decrease at Ricketts Point. There were no major changes in abundance
observed for other species (Figure 6.3).
The average blacklip abalone length at Ricketts Point increased from 77 mm to 92 mm, while
the average length at Halfmoon Bay decreased from 88 mm to 85 mm (Figure 6.4).
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PPB Sanctuaries Subtidal Reef Monitoring
Ricketts Point MS
Halfmoon Bay
Abundance
Haliotis rubra
200
200
150
150
100
100
50
50
0
0
Heliocidaris erythrogramma
1200
800
800
400
400
0
0
Abundance
1200
Abundance
Coscinasterias muricata
21
21
14
14
7
7
0
0
Abundance
Tosia australis
20
20
15
15
10
10
5
5
0
2003
2004
2005
0
2003
2006
Year
2004
2005
2006
Year
Figure 6.2 Abundances of selected invertebrate species in the vicinity of Ricketts Point Marine
Sanctuary.
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Length (m m )
Ricketts Point
Halfmoon Bay
120
120
110
110
100
100
90
90
80
80
70
70
60
2003
2004
2005
60
2003
2006
Time
2004
2005
2006
Time
Figure 6.3. Mean sizes (± 95% confidence intervals) of black lip abalone Haliotis rubra at Ricketts
Point Marine Sanctuary and Halfmoon Bay reference site.
6.4 Fishes
Fish assemblages were more diverse, and larger species were more abundant, at Ricketts
Point and Halfmoon Bay than at other sites in northern Port Phillip Bay. At both sites, the fish
assemblage was numerically dominated by the southern hulafish Trachinops
caudimaculatus. During the first survey, transient species including a school of Australian
salmon Arripis trutta and several subadult male snapper Chrysophrys auratus were observed
at Ricketts Point. Other prominent large species of fish included zebra fish Girella zebra,
horseshoe leatherjacket Meuschenia hippocrepis and moonlighter Tilodon sexfasciatus.
Species of leatherjacket included toothbrush leatherjacket Acanthaluteres vittiger, yellow
tailed leatherjacket Meuschenia flavolineata and six spined leatherjacket Meuschenia
freycineti. There were lower abundances of fish at Halfmoon Bay than at Ricketts Point,
although the assemblage was composed of similar species. Species at this site included
snapper Crysophrys auratus, zebra fish Girella zebra, moonlighter Tilodon sexfasciatus,
toothbrush leatherjacket Acanthaluteres vittiger and horseshoe leatherjacket Meuschenia
hippocrepis.
Both Trachinops caudimaculatus and Neoodax balteatus were variable in abundance
between the three surveys. There was an increasing trend in Neoodax balteatus at Halfmoon
Bay, and a stong decreasing trend in trachinops caudimaculatus at Ricketts Point (Figure
6.4).
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Ricketts Point MS
Halfmoon Bay
Abundance
Trachinops caudimaculatus
700
700
600
600
500
500
400
400
300
300
200
200
100
100
0
0
Abundance
Neoodax balteatus
30
30
20
20
10
10
0
2003
2004
2005
0
2003
2006
Year
2004
2005
2006
Year
Figure 6.4. Abundances of southern hulafish Trachinops caudimaculatus and little rock whiting
Neoodax balteatus in the vicinity of Ricketts Point Marine Sanctuary.
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7. REFERENCES
Clarke K. R. (1993) Non-parametric multivariate analyses of changes in community structure.
Australian Journal of Ecology 18: 117-143.
Dayton P. K., Tegner M. J., Edwards P. B. and Riser K. L. (1998) Sliding baselines, ghosts,
and reduced expectations in kelp forest communities. Ecological Applications 8: 309-322.
Ebeling A. W., Laur D. R. and Rowley R. J. (1985) Severe storm disturbances and reversal
of community structure in a southern California kelp forest. Marine Biology 84: 287-294.
Edgar G. J. (1998) Impact on and recovery of subtidal reefs. In: Iron Barron Oil Spill, July
1995: Long Term Environmental Impact and Recovery. Tasmanian Department of Primary
Industries and Environment, Hobart, pp273-293.
Edgar G. J., Barrett N. S. (1997) Short term monitoring of biotic change in Tasmanian marine
reserves. Journal of Experimental Marine Biology and Ecology 213: 261-279.
Edgar G. J. and Barrett N. S. (1999) Effects of the declaration of marine reserves on
Tasmanian reef fishes, invertebrates and plants. Journal of Experimental Marine Biology and
Ecology 242: 107-144.
Edgar G. J., Moverly J., Barrett N. S., Peters D., and Reed C. (1997) The conservationrelated benefits of a systematic marine biological sampling program: the Tasmanian reef
bioregionalisation as a case study. Biological Conservation 79: 227-240.
Edmunds M. and Hart S. (2003) Parks Victoria Standard Operating Procedure: Biological
Monitoring of Subtidal Reefs. Parks Victoria Technical Series No. 9, Parks Victoria,
Melbourne.
Edmunds M., Hart S., Jenkins S. and Elias J. (2003a) Victorian Subtidal Reef Monitoring
Program – The reef biota at Wilsons Promontory Marine National Park. Parks Victoria
Technical Series No. 6, Parks Victoria, Melbourne.
Edmunds M, Hart S, Elias J and Power B (2003b) Port Phillip Bay Channels Deepening
Environmental Effects Statement – Marine Ecology Specialist Studies. Volume 6: Shallow
Reef Biota. Report to Port of Melbourne Corporation and Parsons Brinckerhoff. Australian
Marine Ecology Report 163, Melbourne, 139 pp.
Edmunds E, Roob R. and Ferns L. (2000) Marine Biogeography of the Central Victoria and
Flinders Bioregions – a Preliminary Analysis of Reef Flora and Fauna. In: L. W. Ferns and D.
Hough (eds). Environmental Inventory of Victoria’s Marine Ecosystems Stage 3 (Volume 2).
Parks, Flora and Fauna Division, Department of Natural Resources and Environment, East
Melbourne. Australia.
Faith D., Minchin P. and Belbin L. (1987) Compositional dissimilarity as a robust measure of
ecological distance. Vegetation 69: 57-68.
Holling C. S. (1978) Adaptive Environmental Assessment and Management. Wiley,
Chichester.
Krebs C. J. (1999) Ecological Methodology, Second Edition. Benjamin/Cummings, Menlo
Park.
Meredith C. (1997) Best Practice in Performance Reporting in Natural Resource
Management. Department of Natural Resources and Environment, Melbourne.
41
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PPB Sanctuaries Subtidal Reef Monitoring
Roob R., Edmunds M. and Ball D. (2000) Victorian Oil Spill Response Atlas: Biological
resources. Macroalgal Communities in Central Victoria. Unpublished report to Australian
Marine Safety Authority, Australian Marine Ecology Report No. 19, Melbourne.
H. Sweatman, D. Abdo, S. Burgess, A. Cheal, G. Coleman, S. Delean, M. Emslie, I. Miller,
K. Osborne, W. Oxley, C. Page, A. Thompson. (2003) Long-term Monitoring of the Great
Barrier Reef. Status Report Number 6. Australian Institute of Marine Science, Townsville.
8. ACKNOWLEDGEMENTS
This project was funded by Parks Victoria and supervised by Dr Anthony Boxshall.
We are grateful for the field assistance of Jeff Giddins of Scuttlebut Scuba and Fishing
Charters.
42