Sea turtles

The impacts of sea-level rise on the index nesting beach on Klein Bonaire for three species of sea turtle

Abstract:

Globally, all extant sea turtles species are endangered due to centuries of uncontrolled exploitation, furthermore they face future threats from climate change. The Caribbean is home to six of the seven extant marine turtle species. Sea turtles have various nesting and feeding grounds across the Caribbean but return to their natal beaches to breed. This study focuses on nesting sea turtles in Bonaire, a small island in the south of the Caribbean, which has three breeding species; the Green, Loggerhead and Hawksbill turtle. The index beach is “No Name” beach on the small islet of Klein Bonaire, which is 800m west of Bonaire.

Global sea-level rise projections range between 0.18-0.59m by 2100 (IPCC, 2007). However, the Caribbean region could experience 25% greater sea-level rise than the global average with suggestions up to 1.6m. Sea-level rise threatens nesting beaches and is expected to negatively impact the sea turtles. This investigation measured beach profiles along “No Name” beach to create contours of elevation. The nests were identified, monitored and plotted onto maps. Analysis of the distance from the nest to the HTM and elevations of nests indicate that Loggerheads are more at risk from sea-level rise. However for all sea-level rise scenarios there will be beach area and nests lost (using 2012 data). Where natal beaches cannot retreat, they may be lost to sea-level rise; turtles must adapt to climate changes or will face an even greater population decline. 

Date
2012
Data type
Other resources
Theme
Research and monitoring
Geographic location
Bonaire
Author

BioNews 7 - August 2013

This month’s issue focuses attention on three successful conservation efforts of local NGOs, which are using monitoring to guide their field-based conservation efforts, safeguarding nature in the Dutch Caribbean.

The three profiled success stories are:

As always, you will also find in this seventh issue:

Date
2013
Data type
Media
Theme
Education and outreach
Research and monitoring
Geographic location
Aruba
Bonaire
Curacao
Saba
St. Eustatius
St. Maarten
Author

Global Analysis of Anthropogenic Debris Ingestion by Sea Turtles

Abstract:

Ingestion of marine debris can have lethal and sublethal effects on sea turtles and other wildlife. Although researchers have reported on ingestion of anthropogenic debris by marine turtles and implied inci- dences of debris ingestion have increased over time, there has not been a global synthesis of the phenomenon since 1985. Thus, we analyzed 37 studies published from 1985 to 2012 that report on data collected from before 1900 through 2011. Specifically, we investigated whether ingestion prevalence has changed over time, what types of debris are most commonly ingested, the geographic distribution of debris ingestion by marine turtles relative to global debris distribution, and which species and life-history stages are most likely to ingest debris. The probability of green (Chelonia mydas) and leatherback turtles (Dermochelys coriacea) ingesting debris increased significantly over time, and plastic was the most commonly ingested debris. Turtles in nearly all regions studied ingest debris, but the probability of ingestion was not related to modeled debris densities. Furthermore, smaller, oceanic-stage turtles were more likely to ingest debris than coastal foragers, whereas carnivorous species were less likely to ingest debris than herbivores or gelatinovores. Our results indicate oceanic leatherback turtles and green turtles are at the greatest risk of both lethal and sublethal effects from ingested marine debris. To reduce this risk, anthropogenic debris must be managed at a global level. 

Date
2013
Data type
Scientific article
Theme
Research and monitoring

Strategic Plan for Eliminating the Incidental Capture and Mortality of Leatherback Turtles in the Coastal Gillnet Fisheries of Trinidad and Tobago

Abstract:

Accidental entanglement of leatherback sea turtles (Dermochelys coriacea) in the gillnet fisheries of Trinidad is the most serious conservation problem faced by the species and threatens to undo several years of proactive conservation and innovative management by the government of Trinidad and Tobago and many local non-government organizations (NGOs). The entangle- ment problem also places a severe strain on the ability of Trinidad fishers to operate economically, and is so severe that many are unable to fish during the sea turtle nesting season.

Undisputed among stakeholders is that incidental capture is the largest single source of mortality to leatherbacks in the country, killing more leatherbacks than all other factors combined. Because it supports the second largest known nesting aggregation in the world, the Republic of Trinidad and Tobago plays a uniquely important role in the survival of this species on a global scale. With this in mind, incidental capture and mortality to reproductively active females in waters under the Republic’s jurisdiction constitute a major threat to this Critically Endangered (cf. IUCN) species on both Atlantic basin and global scales.

In an attempt to open a dialogue on these issues, and facilitate a stakeholder driven process of solution-making, a National Consultation was hosted by the Wider Caribbean Sea Turtle Conservation Network (WIDECAST) and the Fisheries Division (Ministry of Agriculture, Land and Marine Resources) in February 2005. Invited participants included fishers drawn from all affected communities, including representatives from Tobago, local and national NGOs, the government’s primary natural resource management agencies, the Ministry of Foreign Affairs, and a small number of international fishing and conservation experts.

The goal of the meeting was to review the problem of sea turtle bycatch in coastal gillnet fisheries, in particular along the north and east coasts of Trinidad where most leatherback nesting takes place, and to apply the shared expertise of the forum to devising a series of potential solutions suitable for field-testing and evaluation by fishers and natural resource management professionals. To this end, twin objectives were proposed: fishers must be better off economically as a result of any proposed solution to the bycatch crisis, and the incidental capture and mortality of leatherback sea turtles in coastal fisheries must cease.

The goal of the meeting was met through technical presentations in a conference setting, open- forum question and answer sessions, an all-day field excursion to coastal fishing communities and fishing depots, Working Group discussions, plenary consensus on recommendations, and publication of this Proceedings document.

Participants acknowledged that the problem is a difficult one, and that no single solution would likely suffice for all areas and all fisheries. Thus it was proposed that a series of investigations be designed to evaluate, under realistic field conditions, various bycatch reduction options including: new bait types (e.g. artificial, dead and non-traditional baits) to enhance hook-and- line fishing as a replacement for gillnets; new technologies, techniques, or gear modifications (e.g. power take-up reels, alternate net materials, FADs; net-fishing at different depths); and creative approaches to net avoidance (e.g. sonic ‘pingers’, shark silhouettes). It was agreed that each of these options should receive equal weight during the experimental phase, and that the results of each trial should determine subsequent experimental priorities.

New regulatory regimes, and in particular the implementation of time and area closures, were also discussed. The recommendation was made that gillnets be banned from 1 March to 31 May within a region extending from the south end of Fishing Pond Beach to the west end of Paria Beach, and extending 8km offshore. Other types of gear would be allowed. There was concern over the government’s capacity to enforce the closure, however, and the need for improved marine resource management capacity was noted. Also noted was the need to harmonize the Fisheries Act (specifically the 1975 Protection of Turtles and Turtle Eggs Regulations) and the Conservation of Wild Life Act, such that protection to the leatherback turtle at all times was unambiguous.

With regard to evaluating fishery alternatives, the meeting uniformly agreed that active fishermen must be involved in the testing and development of each new method, with oversight and assistance by relevant experts. It was proposed that the best mechanism for initiating the field-testing component would be to invite proposals from relevant national and international experts (see “Project Implementation Notes”), and that fund-raising, including the paid participation of fishers, would need to occur on a case-by-case basis.

Furthermore, there was consensus that the following criteria be taken into account when evaluating the various mitigation options:

  • What - will the experiment measure (objectives and variables)?
  • How - will the experiment be conducted (materials and methods)?
  • Where - will the experiment be conducted?
  • Who - will conduct and evaluate the results of the experiment?

There was also consensus that the following Evaluation Criteria be adopted:

  •  Can the new technique catch fish?
  •  Is it economically viable (i.e. producing equivalent or increased revenue)?
  •  Does it reduce adverse impact to leatherback sea turtles?
  •  Can it be managed/regulated?
  •  Is it logistically feasible for local conditions?
  •  Is it biologically and commercially sustainable?
  •  Will it be supported/accepted by the stakeholders?

Finally, there was widespread interest among participants that a mechanism be created, perhaps by Government, to facilitate an ongoing dialogue between fishers and natural resource managers, and embracing the expertise of communities and NGOs, on subjects of fisher concern regarding the bycatch issue and the hardships endured during the seasonal struggle to fish in the presence of large numbers of leatherback turtles. 

Date
2005
Data type
Research report
Theme
Governance
Education and outreach
Research and monitoring
Report number
WIDECAST Technical Report No. 5

WIDECAST Sea Turtle Recovery Action Plan for the Netherlands Antilles

Abstract:

The Netherlands Antilles consists of five Caribbean islands. The leeward islands are Curaçao and Bonaire, close to the mainland of Venezuela, while the windward islands are St. Maarten, St. Eustatius, and Saba, forming part of the Lesser Antilles archipelago. The sea turtles which are most abundant in the waters of the Netherlands Antilles are the green-back turtle, or tortuga blanku (Chelonia mydas) and the hawksbill, or karet (Eretmochelys imbricata). This is not surprising, since these species are generally found closely associated with Thalassia seagrass meadows and coral reefs, respectively, and these habitats are widespread in the Netherlands Antilles. The loggerhead, or kawama (Caretta caretta) is less common and often encountered further offshore, although it is also present in some of the inner bays, such as Lac Bay in Bonaire. The leatherback, or driekiel (sometimes spelled drikil) (Dermochelys coriacea) is rare, being present on a seasonal basis to nest. Information from all five islands indicates that sea turtles used to be far more abundant than they are today.

The sea turtle populations that remain in the Netherlands Antilles are stressed for many reasons. A major consideration is the destruction and/or modification of habitat. Almost all nesting beaches have disappeared or have been degraded because of sand mining or commercial and touristic development of the coast; further, beaches are altered or trampled for recreation. Light from nearshore buildings disorients hatchlings, confusing them so that they do not find the sea, while too many people scare the females away. Pollution from both land-based and marine sources (sewage, garbage, and oil) is an increasing problem throughout the Caribbean, and the Netherlands Antilles is no exception. Anchoring and careless diving behavior have degraded coral reef ecosystems and diseases (e.g., natural bleaching, black band disease) have also taken their toll. The extent to which these phenomena have reduced important turtle foraging grounds has not been quantified. Marine turtles are also vulnerable to a tumor disease known as fibropapillomas that has affected our green turtles and is known to be fatal in other areas. Finally, there is the legacy of more than three centuries of uncontrolled harvest. While progress has been made toward protecting turtles in the Netherlands Antilles, particularly in Bonaire, regulatory mechanisms and enforcement remain inadequate on the whole.

The objective of this document is not only to summarize the status of sea turtles, including agents that may compromise their continued survival, but also to recommend solutions to contemporary stresses. First, it is clear that a more comprehensive knowledge of essential habitats is necessary. This will require systematic surveys of potential foraging and nesting areas. The best areas should be considered for protected status. Within these areas, activities that threaten sea turtles or the habitats upon which they depend should be controlled or prohibited. Specific management plans for important foraging and nesting areas need to be developed and implemented. This will require the involvement of local authorities who have the responsibility to draft regulatory guidelines and provide enforcement. It is of great importance that materials be developed to educate the public (residents, especially fishermen, and tourists) as to why all these measures for the protection of sea turtles are necessary. Such materials should emphasize national pride as well, noting that the Netherlands Antilles is taking its place in the community of Wider Caribbean nations in recognizing the depleted nature of sea turtle stocks, and in working to ensure that these animals do not disappear from our region.

An essential part of protecting sea turtles involves updating national and local laws and regulations. In the Netherlands Antilles, on the national as well as the island levels, much can be done to improve conservation legislation. Some of the islands, especially Bonaire, have good legislation in place to protect sea turtles. Intermediate legislation is in place in Saba; Curaçao, St. Maarten, and St. Eustatius have no legislation whatsoever to protect turtles. Comprehensive island legislation, including provisions for penalty and enforcement, is seen as a priority for the Netherlands Antilles. It is also recommended that relevant international and regional protective legislation (CITES, UNEP Cartagena Convention, and MARPOL) be implemented. Finally, suitable legislation strengthening enforcement is a necessity.

A Netherlands Antilles Sea Turtle Project is proposed with the primary goal of achieving a sustained recovery of depleted sea turtle stocks in the Netherlands Antilles and secondary goals of gathering more data on the local distribution of turtles (especially nesting activity) and promoting a public understanding of why the conservation and recovery of sea turtles in the Netherlands Antilles is necessary. To achieve these goals, complementary action is required at both the island and national levels. It is essential that each island of the Netherlands Antilles implement its own sea turtle project. Because each island has its own local government, NGOs and legislation, the implementation of sea turtle conservation and recovery actions will be most effective at the island level. In each case this will require a Lead Organization to support and execute the project, a timetable and budget, a realistic survey and monitoring program to gather data on turtle distribution and nesting, lobbying efforts on behalf of improved legislation and enforcement, and increased public awareness and involvement.

In concert with the island projects, action by the Central Government is needed to link the island programs together and to execute important national and international legislation. The government agency responsible for the environment is the Department of Public Health and Environment, which is currently being restructured to place greater emphasis on the environment. As part of an effort at national integration, the Department should (1) urge every island to design and implement a local sea turtle conservation project, (2) follow-up on the island projects and support local organizations, (3) adopt national legislation to protect sea turtles (ideally within the framework of holistic legislation protecting marine resources and the marine environment in general), (4) produce and distribute general information on regulations and the protection of sea turtles, (5) establish communication and information exchange among the islands by means of a newsletter or other mechanism, and (6) raise and allocate funds for local sea turtle conservation. Cooperative programs with neighboring nations should be initiated at the national level.

Using this decentralized approach, it is anticipated that several island programs will be imple- mented in a relatively short period of time, perhaps by 1995. Specific results and outputs are expected to include (1) comprehensive legislation for each island, as well as at the national level, that protects all sea turtles at all times and major parts of their environment (the latter may be achieved by the designnation and support of Marine Parks or other conservation areas), (2) a better knowledge of the distribution and abundance of sea turtles, especially the nesting beaches of these animals, (3) detailed recommendations to each island government regarding the protection and conservation of suitable nesting beaches (a balance between development and conservation must be sought in this regard), and (4) a better understanding on the part of the citizenry of why it is important to protect and conserve sea turtles for future generations. 

Date
1992
Data type
Research report
Theme
Governance
Research and monitoring
Report number
CEP Technical Report No. 11
Geographic location
Bonaire
Curacao
Saba
St. Eustatius
St. Maarten
Author

Sea Turtles as Flagships for Protection of the Wider Caribbean Region

Abstract:

Sea turtles are emerging as one of the most popular icons of the marine environment. Capitalising on their charismatic image, a remarkable variety of stake- holders, including scientists, conservationists, community-based organisations, corporations, and governments, have sought to utilise sea turtles as flagships. This paper focuses on the Wider Caribbean Region, emphasising small island developing states, and explores the ways, and appropriateness, of using sea turtles as flagships to motivate people to consider complex contemporary management and policy issues, including those associated with protected areas, fisheries, multilateral conservation of shared species and seascapes, and tourism. 

Date
2005
Data type
Scientific article
Theme
Governance
Legislation
Research and monitoring
Geographic location
Aruba
Bonaire
Curacao
Saba bank
St. Eustatius
St. Maarten

Research and Monitoring Report 2011 - Sea Turtle Conservation Bonaire

Sea Turtle Conservation Bonaire (STCB) is a non-governmental, non-profit, research and conservation organization that began in 1991. Our mission is to ensure the protection and recovery of Bonaire’s sea turtle populations throughout their range.

Three species of sea turtles are found in the waters of Bonaire. They are: the hawksbill, the green turtle, and the loggerhead. The hawksbill is considered “critically endangered” throughout its global ranges; and the green and loggerhead considered “endangered”. Bonaire offers a relatively safe haven for foraging juvenile hawksbill and green turtles, as well as critical nesting grounds for hawksbill, loggerhead, green, and the incidental leatherback.

In 2011, we completed our 9th year of systematic research on the sea turtles of Bonaire. In this report you will read about the methods and results of our research and monitoring activities, which include nesting beach monitoring, foraging ground surveys, and turtle migration tracking. With our nesting beach monitoring, we track turtle nesting activity, determine nest size and productivity, and estimate the number of hatchlings produced. With our foraging ground surveys we tag, measure and photo- graph individual turtles and establish catch-per-unit-effort measures of turtle abundance. We inspect our captured turtles for signs of illness or injury, including fibropapillomatosis, which we first saw on green turtles at Lac Bay in 2005. Our recapture of previously tagged turtles provides valuable insight into turtle residency duration, recruitment, home range, growth rates, and habitat quality. With satellite telemetry, we are able to identify the migration paths and distant feeding grounds used by our breeding and nesting turtles.

Using the information we gather in our research and monitoring activities, we are able to identify and implement conservation efforts to improve the direct protection of Bonaire’s sea turtles and their environments. Our activities also include partnerships and initiatives that focus on the bigger picture and use sea turtle conservation as a focal point to drive and stimulate conservation awareness and efforts. 

Date
2012
Data type
Research report
Theme
Research and monitoring
Geographic location
Bonaire
Author