HT2 Doc. 8
CONVENTION ON INTERNATIONAL TRADE IN ENDANGERED SPECIES
OF WILD FAUNA AND FLORA
____________________
Second CITES wider Caribbean hawksbill turtle dialogue meeting
Grand Cayman (Cayman Islands), 21–23 May 2002
REPORT TO THE RANGE STATES ON THE DEVELOPMENT OF HAWKSBILL (ERETMOCHELYS
IMBRICATA) POPULATION MONITORING PROTOCOLS FOR THE WIDER CARIBBEAN
This document was prepared by the working group on the development of standardized population
monitoring protocols and the identification of index sites.
The need and importance for long term monitoring of sea turtle populations in the Caribbean has
long been recognized and dates to the early 1980’s with the first Western Atlantic Turtle
Symposium (WATS I). It was further reaffirmed as recently as a meeting of 29 Caribbean states
and territories in Santo Domingo, Domincan Republic, November 16-18,1999 ( Marine Turtle
Conservation in the Wider Caribbean Region: A Dialog for Effective Regional Management).
Standardized population monitoring protocols were most recently identified as a fundamental need
for regional management of Caribbean hawksbill populations at the1st Hawksbill Dialogue Meeting
in Mexico City, Mexico May 15-17, 2001 which was convened by the CITES Secretariat. At this
important gathering a working group, comprised of representatives from five countries, was
developed to take on the task of developing these protocols and identifying index sites. It is in this
context that these protocols should be understood and used as they support the recommendations
of many that preceeded our group as well as the broad goals and aspirations of the Inter-American
Sea Turtle Convention and the SPAW Protocol of the Convention for the Protection and
Development of the Marine Environment of the Wider Caribbean Region.
The working group included representatives from Barbados, Bermuda, Costa Rica, Mexico, Puerto
Rico and the United States. A workshop was subsequently organized by the U.S to develop draft
protocols and recommended index monitoring sites. The workshop was held in Miami, Florida,
February 26-28, 2002. Thirteen participants from the working group countries and three invited
hawksbill experts experienced in nesting beach or foraging grounds surveys in the region attended
(attachment 1). This report represents the conclusions of the working group. Only one issue could
not be entirely resolved, that being the use of turtle harvest data as an additional method of
population trends assessment proposed by the Cuban representatives. The group agreed that data
collected from the Cuban harvest could conceptually be used as another method of assessing
population trends, provided appropriate and standardized criteria are applied. However, the
majority of the group felt this methodology should not be included as part of the foraging ground
monitoring protocol and index sites but rather as a separate and unique situation which may
provide additional data complementing population trend data from foraging and nesting grounds.
The following protocols are considered drafts and will be discussed at the 2nd Hawkbill Dialogue
Meeting scheduled in the Cayman Islands, May 21-23, 2002. It is our hope that representatives at
this meeting will come prepared to discuss any needed modifications or to endorse the protocols
as written. Endorsing the list of index sites does not commit a particular government to funding
monitoring projects at these sites. We do hope an endorsement will mean a commitment to raise
the priority of these monitoring projects for government funding support as well as supporting the
efforts of those outside government to initiate long term monitoring projects at these index sites.
Index Nesting Beach Survey Protocol for Caribbean Hawksbills
Sea Turtles depend on a variety of coastal and marine environments during their life cycle and for
HT2 Doc. 8 – p.1
different life stages. This in combination with other biological factors such as long time period to
reach sexual maturity and nesting periodicity pose unique challenges in monitoring populations to
determine long term trends. Monitoring nesting populations is logistically the most easily
accomplished method of surveying populations and for that reason the most commonly practiced
survey methodology. These special and complicated conditions require the particular development
of protocols that permit the generation of precise and comparable information. The key element in
ensuring data is suitable for trend analysis is the consistent and long term application of
standardized techniques at the selected index sites. Long term here means at least 8 years due to
the 2.7 average nesting remigration interval of the hawksbill (Bjorkland 2001).
The purpose of this protocol is to guide the collection of hawksbill nesting data to measure the
tendency of the nesting as a change in relative abundance over time. The application of this
protocol if implemented at the many recommended index sites will give a more complete
assessment of the population status of hawksbills in the Caribbean. However, any analyses must
also recognize the unique status of individual nesting colonies that may not reflect the general
trend of the Caribbean meta-population.
Survey Boundaries
Survey boundaries of index nesting beaches must be specifically set and adhered to from year to
year. Selection of survey boundaries (survey length) should take into consideration the long-term
potential for survey continuation in accordance with the index survey protocols.
The survey area must be representative of local nesting, for example, in the case of cays, one or
more cays may comprise a “single” index nesting beach.
Survey Zones
The establishment of survey zones within the broader index beach is recommended if finer scale
nesting data are needed for addressing management questions at the local level.
Survey Frequency
Survey frequency (number of days per week the survey is conducted) must be specifically set and
adhered to from year to year.
Ideally, nesting surveys should be conducted daily, however, logistical considerations may
preclude daily surveys.
A survey frequency of every other day is considered a minimal requirement to reduce survey error.
In the case of remote, isolated nesting beaches, where logistics preclude every other day surveys,
a reduced survey schedule of 2-3 times evenly spaced across the week may be sufficient, provided
all other criteria, including surveyor training are met.
Survey Period
The survey period should encompass the peak of the nesting season and should be designed to
allow for shifts in the peak of the nesting season from year to year
Beaches that have not been previously surveyed, or for which the nesting season has not been
defined, will require pilot studies to identify the peak of the nesting season prior to setting the
survey period. Pilot studies should be conducted for a period of 3 years, during which time the
complete nesting season will be surveyed.
Ideally, the complete nesting season should be encompassed, however, the minimal survey period
is 8 weeks, shorter survey periods may be appropriate depending on local conditions and a
complete understanding of variability in the nesting season
HT2 Doc. 8 – p.2
Survey Time
Ideally, index nesting beaches surveys should be conducted as early in the morning as possible,
when conditions are optimal for discerning crawls.
Nest Verification
Ideally, surveyors will be sufficiently trained to confirm nests by evaluating track and nest site
characteristics. If there is a question whether a crawl has resulted in a nest, the presence or
absence of eggs should be verified by hand digging.
Surveyor Training
Training should include observations of nesting turtles to ensure that surveyors have a thorough
understanding of the behaviors that result in crawl and nest characteristics, this is key to correctly
identifying nests vs. non-nesting emergences.
Training should also include “hands-on” training evaluating crawls on the survey beach with
experienced personnel.
New personnel should work side-by-side with experienced personnel until the project leader is
sufficiently convinced that new personnel have the knowledge and skills necessary to perform an
accurate survey.
What data will be collected?
FOR EACH SURVEY SEASON:
Physical Description of Boundaries (Survey Area)
Start and Stop Dates of Survey
# of Days per Week Surveyed
Narrative describing significant changes at the nesting beach that may influence nesting,
other metadata important to interpreting nesting information, including any deviations
from the protocols
FOR EACH SURVEY:
Survey Beach (if multiple beaches comprise the index site)
Survey Day
Survey Start and End Time
Surveyor Name(s)
Number of Nesting Emergences (includes poached and depredated nests) (by zone if
the beach is sub-divided)
Number of Non-nesting Emergences (by zone if the beach is subdivided)
Literature Cited
Bjorkland, R. 2001. Monitoring Population Trends, pp. 137-138. In K.L. Eckert and F. Alberto
Abreu-Grobois (eds), Proceedings of the Regional Meeting: Marine Turtle conservation in the
Wider Caribbean Region: A Dialogue for Effective Regional Management, “ Santo Domingo, 16-18
HT2 Doc. 8 – p.3
November 1999. WIDECAST , IUCN-MTSG, WWF, and UNEP-CEP. xx + 154 pp.
HT2 Doc. 8 – p.4
Table 1: Selection criteria of nesting beaches in the Caribbean Sea
Level I:
1. Some information of nesting activity
2. Evidence of important nesting colony (Size, abundance or Number of turtles)
3. Some evidence that continuity in monitoring can be expected since a program
already in place (Persistent in the collection of data. Historical of the project)
4. Possibility of developing a monitoring project in the site.
5. Need to have an adequate spread across geographic area to have
representative selection
Level II:
[additional characteristics that would help assure representativity in the selected index
sites- select sites so as to include all of the characteristics]
1. Level of protection: High level of protection / no protection / isolated
2. Availability of knowledge on trends: Information on trends is available / Trends
are unknown
3. Degree of development in the area: Some development / no development
4. Historic Status: Data suggesting important nesting colony in the past
Table 2. Caribbean area locations considered currently or historically important as
hawksbill nesting beaches.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Nesting Beach
Isla Aguada
Punta Xen
San Lorenzo
Chenkan
Sabancuy
Isla del Carmen
Chacahito
Las Colorados – El Cuyo
Isla Holbox
Celestun
Isla Contoy
Manatee Bar
Manabique Peninsula
Cayo Cochinos
Utila Island
Pearl Cays
HT2 Doc. 8 – p.5
Country
Mexico
Mexico
Mexico
Mexico
Mexico
Mexico
Mexico
Mexico
Mexico
Mexico
Mexico
Belize
Guatemala
Honduras
Honduras
Nicaragua
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
El Cocal Beach
Nicaragua
San Andres Islands
Colombia
Tortuguero
Costa Rica
Cahuita
Costa Rica
Chiriqui Beach
Panama
Bastimentos Island National Park
Panama
Isla del Rosario
Colombia
Islas los Roques
Venezuela
Los Garzos y Guinimita
Venezuela
Bonaire
Netherlands Antilles
Bahamas
Doce Leguas Cays
Canarreos Archipelago
Ambergris and Seal Keys
Portland Bight Cays
Luana/Font Hill
Jaragua
Mona Island
Humacao
Sandy Point
East Beaches
Buck Island
Jumby Bay
St. Eustatius
Scrub Island
Guadeloupe
Hilton
Sandy Island
Isle a Caille
La Tante
Bahamas
Cuba
Cuba
Turks & Caicos (UK)
Jamaica
Jamaica
Dominican Republic
Puerto Rico
Puerto Rico
USVI
USVI
USVI
Antigua
Netherlands
Anguilla (UK)
Guadeloupe
Barbados
Grenada
Grenada
Grenada
Index Foraging Habitat Survey Protocol for Caribbean Hawksbill Turtles
Assessment of sea turtle population trends has largely been based on long-term monitoring of the
seasonal beach nesting activity of adult females. Unfortunately, observing only female nesting
activity provides insufficient information for stock assessment because (1) adult females may not
nest every year and (2) no information is provided on demographic structure because the
immature, adult male and non-breeding female components are not sampled (Chaloupka and
Limpus, 2001). Therefore, any reliable assessment of marine turtle stocks requires sampling in the
foraging grounds to include individuals not encountered on the nesting beach.
Foraging hawksbills may be present in many of the shallow (<50m), mostly hard-bottom habitats of
the Caribbean. Clearly, conducting a census of all these areas is an improbable task and some
sort of sampling methods are required. It is therefore the aim of this protocol to provide guidance
on appropriate sampling methods, in conjunction with considerations on collecting representative
data. The protocol has adopted many of the recommendations that emerged from a March 2000
workshop held in Gainesville, Florida, on the design of in-water marine turtle population trend
assessment studies ("Workshop on assessing abundance and trends for in-water sea turtle
populations", Bjorndal and Bolten, 2000). The emphasis of this protocol is on establishing index
methods for measuring trends in relative abundance at fixed locations.
HT2 Doc. 8 – p.6
Survey design
The design of monitoring programs to detect trends in relative hawksbill abundance on foraging
grounds needs careful consideration with regards to selection of sites and sampling methods. The
proposed, region-wide assembly of monitoring sites should encompass many of the foraging
grounds recognized as currently or historically important (Table 1). Selection of index monitoring
sites should attempt to represent (1) a range of threat and protection levels, (2) a variety of turtle
life stages, and (3) a range of turtle population densities. The sampling strategies at each index
foraging site should ideally be structured in a manner that allows inference to a larger area of
interest. Actual site selection and determining the most appropriate sampling protocol to use there
will typically require pilot surveys or some form of reconnaissance. Certain preliminary data are
also useful to evaluate the resolving power of a proposed methodology for the detection of trends
in population abundance (see Gerrodette and Brandon, 2000).
Survey methods
It is important to realize that survey methods do not necessarily need to be standardized among
the different studies in the region. However, each study must be highly consistent in applying any
techniques once they are adopted. This protocol recommends the use of the following index survey
methods: (1) turtle counts and/or captures by snorkeling and/or SCUBA, (2) captures by tangle net,
(3) boat based turtle count transects, and (4) fishery dependent turtle captures. For an overview of
these methods, see Table 2.
Index calculation
Index estimates of relative abundance can consist of catch per unit effort (CPUE) calculations or
derived from capture-recapture abundance estimators. The CPUE may include turtle sightings as
well as animals actually caught. Of key importance in measuring CPUE is establishing a
quantifiable unit of effort. Soak times of fixed-length tangle nets or fixed-time snorkeling surveys
are examples of measurable effort. Care should be taken to standardize effort between surveys
and/or to quantify the effect of uncontrollable factors, such as water turbidity. Examining the
precision of the adopted relative abundance index is desirable and this may be measured with an
appropriate coefficient of variation, for example by comparison of replicate surveys. Personnel
conducting the surveys need to be adequately trained to insure consistency in their performance.
Survey frequency and timing
Surveys should be conducted at least annually and survey dates should remain constant from year
to year. Ideally, sampling should be conducted during the non-breeding season. However, if
sampling is conducted during the breeding season, then consideration must be given to the fact
that some portion of resident adults will not be present during the sampling period and/or that
transitory adults may be encountered.
Tissue collection
The collection of blood or tissue biopsy samples from captured turtles is highly recommended to
allow for DNA profiling and from that derive the stock composition at the index foraging site. It
should be emphasized that samples should ideally span a number of seasons as the stock
composition could vary over time. While it is understood that many (if not most) of the index site
projects won’t have the capacity to carry out the genetic analysis, collecting samples is relatively
simple, expedient and inexpensive when programs are already “in place”. Collaboration with
genetic laboratories for the actual analysis is usually feasible. If tissue samples are taken,
additional information on sex (if known) and size of the animals would be indispensable. Full
protocols covering the collection, storage and analysis can be found in FitzSimmons et al. (1999).
Reporting survey results
Reporting requirements of the index surveys include the following supplemental information
HT2 Doc. 8 – p.7
(metadata): (1) the name(s) of the person(s) conducting the survey or of the survey coordinator, (2)
survey dates and frequency, (3) a physical description of the study site with location coordinates
and/or a map delineating sampling locations, (4) a biological description of the habitat type(s)
within the study site, (5) the site's legal level of protection (e.g. marine reserve) with description of
threats to turtles, (6) a description of the size structure of the sampled aggregation, and (7) a
qualitative or quantitative assessment of aggregation density. Relative abundance index survey
reports should be made publicly available.
HT2 Doc. 8 – p.8
Table 1. Caribbean area locations considered currently or historically important as
hawksbill foraging grounds, with notes on the life history stages present.
Location
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Country
Campeche Bank
Mexico Both
Yucatán Bank
Mexico Both
Belize Coast
Belize
Islas de la Bahia and
Honduras
Both
Cochinos Cays
Honduran Mosquitia
Honduras
Nicaraguan Coast
Nicaragua
Sargassum Areas off Costa Rica
Costa Rica
Cahuita
Costa Rica
Bastimentos Island NP
Panamá
San Blas (Kuna Yala) Islands
Panamá
San Andrés Archipelago
Colombia
Islas del Rosario
Colombia
Los Roques Archipelago
Venezuela
Bonaire
Netherlands
Antilles
Margarita/Los Testigos Islands
Venezuela
Barbados West Coast
Barbados
Grenadines, Grenada and
St. Vincent and the Grenadines
Northern Windwards
Leeward Islands
Virgin Islands
US and UK
Mona Island
Puerto Rico
Southern Hispaniola
Dominican
Republic
Navassa Island
US
SW Jamaica
Jamaica
Cayman Islands
UK
Doce Leguas
Cuba
SW Coast Isle de Juventud
Cuba
Sabana –Camaguey Archipelago Cuba
Turks and Caicos
UK
Bahamas
Bahamas
Florida Keys
US
Bermuda
UK
HT2 Doc. 8 – p.9
Adults/immatures/both/other
Both?
Both
Both
Pelagic stage?
Immatures
Both
Both
Both
?
Both?
Immatures
Both?
Immatures
Both
Both?
Both?
Both?
Both
Immatures
?
Both?
Immatures
Both
Immatures
Immatures
Both?
Both?
Both?
Immatures
Table 2. Characteristics of recommended methods to estimate trends in relative abundance
of hawksbill turtles on Caribbean area foraging grounds (adapted from Bjorndal and Bolten
(2000), p. 78).
Survey
method
Index
calculation
Cost
Hand capture CPUE
low
Labor
Area covered
medium
small
medium
small
Capture-recapture
low
Tangle net
CPUE
Capture-recapture
low
medium
medium
high
small
small
Transects by boat
CPUE
high
medium
large
Fishery dependent
CPUE
Capture-recapture
low
low
high
high
large
large
Literature cited
Bjorndal, K.A., Bolten, A.B. 2000. Proceedings of a workshop on assessing abundance and trends
for in-water sea turtle populations. U.S. Dep. Commer. NOAA Tech. Mem. NMFS-SEFSC-445,
83p.
Chaloupka, M., Limpus, C. 2001. Trends in the abundance of sea turtles resident in southern Great
Barrier Reef waters. Biological Conservation 102: 235 –249.
FitzSimmons, N., Moritz, C., Bowen, B. W. 1999. Population identification. p. 72-79. In: Research
and Management Techniques for the Conservation of Sea Turtles. Eckert, K.L., Bjorndal, K. A.,
Abreu-Grobois, F. A. and Donnelly, M. (eds.) IUCN/SSC Marine Turtle Specialist Group Publication
No. 4.
Gerrodette, T., Brandon, J. 2000. Designing a monitoring program to detect trends. p. 36-39. In:
Bjorndal, K.A., Bolten, A.B. (eds.) Proceedings of a workshop on assessing abundance and trends
for in-water sea turtle populations. U.S. Dep. Commer. NOAA Tech. Mem. NMFS-SEFSC-445,
83p.
Attachment 1.
List of Participants – Hawksbill Monitoring Protocol Workshop
1. Julia Horrocks University of West Indies, Barbados
2. Jennifer Gray
Ministry of Environment, Bermuda
3. Dalia Salabarria
Agencia de Medio Ambiente, Cuba
4. Felix Moncada
Ministerio de la Industria Pesquera, Cuba
5. Mauricio Garduno
Instituto Nacional de Ecologia, Mexico
6. Carlos Diez
Departamento de Recursos Naturales y Ambientales, PR
7. Robert van Dam
Puerto Rico
8. Didiher Chacon
Asociacion ANAI, Costa Rica
9. Rotney Piedra Ministerio del Ambiente y Energia, Costa Rica
10. Alberto Abreu Marine Turtle Specialist Group, Mexico
11. Yolanda Leon
Grupo Jaragua, Dominican Republic
12. Cynthia Lagueux
Wildlife Conservation Society, Nicaragua
13. Rhema Kerr Jamaica
14. Anne Meylan Florida Fish & Wildlife Conservation Commission, U.S.
15. Barbara Schroeder National Marine Fisheries Service, U.S.
16. Earl Possardt
U.S. Fish & Wildlife Service, U.S.
17. Zandy Hillis
National Park Service, U.S. V. I. (presentation only)
HT2 Doc. 8 – p.10
18. Blair Witherington
only)
Florida Fish & Wildlife Conservation Commission, U.S. (presentation
HT2 Doc. 8 – p.11