Recovery plan

Elkhorn (Acropora palmata) and staghorn (A. cervicornis) corals were listed as threatened under the ESA on May 9, 2006. Elkhorn and staghorn corals were once the most abundant and important species on Atlantic/Caribbean coral reefs in terms of building reef structure. Both elkhorn and staghorn corals underwent precipitous declines in abundance throughout their ranges. No single or collective group of threats may impact all regions of these species’ ranges equally. Multiple threats acting synergistically or cumulatively likely compound impediments to recovery among elkhorn and staghorn coral populations. The threats to these species that are impeding recovery are: disease, increasing
temperature, depensatory population effects, loss of recruitment habitat, sedimentation, anthropogenic abrasion and breakage, predation, inadequacy of existing regulatory mechanisms, natural abrasion and breakage, ocean acidification, and nutrients and contaminants.

The purpose of this recovery plan is to identify a strategy for rebuilding and assuring the long-term viability of elkhorn coral and staghorn coral populations in the wild, allowing ultimately for the species’ removal from the federal list of endangered and threatened species. Actions must be taken to address ocean warming and acidification impacts on these species. Simultaneously, local threat reductions, mitigation strategies, and in and ex situ conservation and restoration actions must be pursued.

The goal of this recovery plan is to increase the abundance and to protect the genetic diversity of elkhorn and staghorn coral populations throughout their geographical ranges while sufficiently abating threats to warrant delisting of both species.

Abstract:

This study presents a comprehensive genetic analysis of stock structure for leatherback turtles (Dermochelys coriacea), combining 17 microsatellite loci and 763 bp of the mtDNA control region. Recently discovered eastern Atlantic nesting populations of this critically endangered species were absent in a previous survey that found little ocean-wide mtDNA variation. We added rookeries in West Africa and Brazil and generated longer sequences for previously analyzed samples. A total of 1,417 individuals were sampled from nine nesting sites in the Atlantic and SW Indian Ocean. We detected additional mtDNA variation with the longer sequences, identifying ten polymorphic sites that resolved a total of ten haplotypes, including three new variants of haplotypes previously described by shorter sequences. Population differentiation was substantial between all but two adjacent rookery pairs, and FST values ranged from 0.034 to 0.676 and 0.004 to 0.205 for mtDNA and microsatellite data respectively, suggesting that male-mediated gene flow is not as widespread as previously assumed. We detected weak (FST = 0.008 and 0.006) but significant differentiation with microsatellites between the two population pairs that were indistinguishable with mtDNA data. POWSIM analysis showed that our mtDNA marker had very low statistical power to detect weak structure (FST \ 0.005), while our microsatellite marker array had high power. We conclude that the weak differentiation detected with microsatellites reflects a fine scale level of demographic independence that warrants recognition, and that all nine of the nesting colonies should be considered as demographically independent populations for conservation. Our findings illustrate the importance of evaluating the power of specific genetic markers to detect structure in order to correctly identify the appropriate population units to conserve. 

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.