Sea Turtle Conservancy

San Pedro, Costa Rica

Sea Turtle Conservancy

San Pedro, Costa Rica
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Fossette S.,University of Strasbourg | Fossette S.,French National Center for Scientific Research | Fossette S.,University of Swansea | Girard C.,University of Strasbourg | And 13 more authors.
PLoS ONE | Year: 2010

Background: Sea turtles are long-distance migrants with considerable behavioural plasticity in terms of migratory patterns, habitat use and foraging sites within and among populations. However, for the most widely migrating turtle, the leatherback turtle Dermochelys coriacea, studies combining data from individuals of different populations are uncommon. Such studies are however critical to better understand intra- and inter-population variability and take it into account in the implementation of conservation strategies of this critically endangered species. Here, we investigated the movements and diving behaviour of 16 Atlantic leatherback turtles from three different nesting sites and one foraging site during their post-breeding migration to assess the potential determinants of intra- and inter-population variability in migratory patterns. Methodology/Principal Findings: Using satellite-derived behavioural and oceanographic data, we show that turtles used Temporary Residence Areas (TRAs) distributed all around the Atlantic Ocean: 9 in the neritic domain and 13 in the oceanic domain. These TRAs did not share a common oceanographic determinant but on the contrary were associated with mesoscale surface oceanographic features of different types (i.e., altimetric features and/or surface chlorophyll a concentration). Conversely, turtles exhibited relatively similar horizontal and vertical behaviours when in TRAs (i.e., slow swimming velocity/sinuous path/shallow dives) suggesting foraging activity in these productive regions. Migratory paths and TRAs distribution showed interesting similarities with the trajectories of passive satellite-tracked drifters, suggesting that the general dispersion pattern of adults from the nesting sites may reflect the extent of passive dispersion initially experienced by hatchlings. Conclusions/Significance: Intra- and inter-population behavioural variability may therefore be linked with initial hatchling drift scenarios and be highly influenced by environmental conditions. This high degree of behavioural plasticity in Atlantic leatherback turtles makes species-targeted conservation strategies challenging and stresses the need for a larger dataset (>100 individuals) for providing general recommendations in terms of conservation. © 2010 Fossette et al.

Fossette S.,University of Swansea | Fossette S.,National Oceanic and Atmospheric Administration | Witt M.J.,University of Exeter | Nalovic M.A.,Virginia Institute of Marine Science | And 27 more authors.
Proceedings of the Royal Society B: Biological Sciences | Year: 2014

Large oceanic migrants play important roles in ecosystems, yet many species are of conservation concern as a result of anthropogenic threats, of which incidental capture by fisheries is frequently identified. The last large populations of the leatherback turtle, Dermochelys coriacea, occur in the Atlantic Ocean, but interactions with industrial fisheries could jeopardize recent positive population trends, making bycatch mitigation a priority. Here, we perform the first pan Atlantic analysis of spatio-temporal distribution of the leatherback turtle and ascertain overlap with longline fishing effort. Data suggest that the Atlantic probably consists of two regional management units: northern and southern (the latter including turtles breeding in South Africa). Although turtles and fisheriesshow highly diverse distributions, we highlight nine areas of high susceptibility to potential bycatch (four in the northern Atlantic and five in the southern/equatorial Atlantic) that are worthy of further targeted investigation and mitigation. These are reinforced by reports of leatherback bycatch at eight of these sites. International collaborative efforts are needed, especially from nations hosting regions where susceptibility to bycatch is likely to be high within their exclusive economic zone (northern Atlantic: Cape Verde, Gambia, Guinea Bissau, Mauritania, Senegal, Spain, USA and Western Sahara; southern Atlantic: Angola, Brazil, Namibia and UK) and from nations fishing in these high-susceptibility areas, including those located in international waters. © 2014 The Authors.

Esteban N.,University of Swansea | van Dam R.P.,Chelonia Inc | Harrison E.,Sea Turtle Conservancy | Herrera A.,University of Exeter | Berkel J.,Statia National Marine Park
Marine Biology | Year: 2015

Satellite transmitters were deployed on three green turtles, Chelonia mydas, and two hawksbill turtles, Eretmochelys imbricata, nesting in the Lesser Antilles islands, Caribbean, between 2005 and 2007 to obtain preliminary information about the inter-nesting, migratory and foraging habitats in the region. Despite the extremely small dataset, both year-round residents and migrants were identified; specifically, (1) two green turtles used local shallow coastal sites within 50 km of the nesting beach during all of their inter-nesting periods and then settled at these sites on completion of their breeding seasons, (2) one hawksbill turtle travelled 200 km westward before reversing direction and settling within 50 km of the original nesting beach and (3) one green and one hawksbill turtle initially nested at the proximate site, before permanently relocating to an alternative nesting site over 190 km distant. A lack of nesting beach fidelity was supported by flipper tag datasets for the region. Tagging datasets from 2002 to 2012 supported that some green and hawksbill individuals exhibit low fidelity to nesting beaches, whereas other females exhibited a high degree of fidelity (26 turtles tagged, 40.0 km maximum distance recorded from original nesting beach). Individual turtles nesting on St Eustatius and St Maarten appear to exhibit behavioural plasticity in their inter-nesting behaviour and post-nesting migration routes in the eastern Caribbean. The tracking and tagging data combined indicate that some of the green and hawksbill females that nest in the Lesser Antilles islands are year-round residents, whilst others may nest and forage at alternative sites. Thus, continued year-round protection of these islands and implementation of protection programmes in nearby islands could contribute towards safeguarding the green and hawksbill populations of the region. © 2015, Springer-Verlag Berlin Heidelberg.

Leroux R.A.,National Oceanic and Atmospheric Administration | Dutton P.H.,National Oceanic and Atmospheric Administration | Abreu-Grobois F.A.,National Autonomous University of Mexico | Lagueux C.J.,Wildlife Conservation Society | And 8 more authors.
Journal of Heredity | Year: 2012

Management of the critically endangered hawksbill turtle in the Wider Caribbean (WC) has been hampered by knowledge gaps regarding stock structure. We carried out a comprehensive stock structure re-assessment of 11 WC hawksbill rookeries using longer mtDNA sequences, larger sample sizes (N = 647), and additional rookeries compared to previous surveys. Additional variation detected by 740bp sequences between populations allowed us to differentiate populations such as Barbados-Windward and Guadeloupe (Fst = 0.683, P < 0.05) that appeared genetically indistinguishable based on shorter 380bp sequences. POWSIM analysis showed that longer sequences improved power to detect population structure and that when N < 30, increasing the variation detected was as effective in increasing power as increasing sample size. Geographic patterns of genetic variation suggest a model of periodic long-distance colonization coupled with region-wide dispersal and subsequent secondary contact within the WC. Mismatch analysis results for individual clades suggest a general population expansion in the WC following a historic bottleneck about 100000-300000 years ago. We estimated an effective female population size (Nef) of 6000-9000 for the WC, similar to the current estimated numbers of breeding females, highlighting the importance of these regional rookeries to maintaining genetic diversity in hawksbills. Our results provide a basis for standardizing future work to 740bp sequence reads and establish a more complete baseline for determining stock boundaries in this migratory marine species. Finally, our findings illustrate the value of maintaining an archive of specimens for re-analysis as new markers become available. © 2012 Published by Oxford University Press.

Ceriani S.A.,Florida Fish And Wildlife Conservation Commission | Roth J.D.,University of Manitoba | Sasso C.R.,National Oceanic and Atmospheric Administration | McClellan C.M.,University of Exeter | And 10 more authors.
Ecosphere | Year: 2014

Stable isotope analysis can be used to infer geospatial linkages of highly migratory species. Identifying foraging grounds of marine organisms from their isotopic signatures is becoming de rigueur as it has been with terrestrial organisms. Sea turtles are being increasingly studied using a combination of satellite telemetry and stable isotope analysis; these studies along with those from other charismatic, highly vagile, and widely distributed species (e.g., tuna, billfish, sharks, dolphins, whales) have the potential to yield large datasets to develop methodologies to decipher migratory pathways in the marine realm. We collected tissue samples (epidermis and red blood cells) for carbon (δ13C) and nitrogen ((δ15N) stable isotope analysis from 214 individual loggerheads (Caretta caretta) in the Northwest Atlantic Ocean (NWA). We used discriminant function analysis (DFA) to examine how well δ13C and (δ15N classify loggerhead foraging areas. The DFA model was derived from isotopic signatures of 58 loggerheads equipped with satellite tags to identify foraging locations. We assessed model accuracy with the remaining 156 untracked loggerheads that were captured at their foraging locations. The DFA model correctly identified the foraging ground of 93.0% of individuals with a probability greater than 66.7%. The results of the external validation (1) confirm that assignment models based on tracked loggerheads in the NWA are robust and (2) provide the first independent evidence supporting the use of these models for migratory marine organisms. Additionally, we used these data to generate loggerhead-specific δ13C and (δ15N isoscapes, the first for a predator in the Atlantic Ocean. We found a latitudinal trend of δ13C values with higher values in the southern region (20-25°N) and a more complex pattern with (δ15N, with intermediate latitudes (30-35°N) near large coastal estuaries having higher (δ15N-enrichment. These results indicate that this method with further refinement may provide a viable, more spatially-explicit option for identifying loggerhead foraging grounds. Copyright: © 2014 Ceriani et al.

Vander Zanden H.B.,University of Florida | Arthur K.E.,University of Hawaii at Manoa | Bolten A.B.,University of Florida | Popp B.N.,University of Hawaii at Manoa | And 4 more authors.
Marine Ecology Progress Series | Year: 2013

While many migratory marine organisms converge at breeding areas, identifying foraging strategies away from these reproductive sites can be challenging. Adult female green turtles Chelonia mydas regularly migrate thousands of kilometers between nesting and foraging areas, making it difficult to identify foraging habitats that support nesting populations and to understand their feeding strategies. In this study, we use stable isotope analysis to investigate the trophic ecology and spatial distribution of foraging green turtles in the Greater Caribbean. Further, we explore the possibility that adult green turtles, originally considered to be herbivores, may, like their counterparts in the Pacific Ocean, display carnivorous feeding strategies. The wide range of carbon and nitrogen isotope values in bulk epidermis observed in the nesting population at Tortuguero, Costa Rica, could indicate that these turtles feed over several trophic levels. Isotopic niches-or the range of 13C and 15N values, which can be ued as a proxy for ecological niche-varied among the 5 green turtle foraging aggregations sampled. Similarly, the isotopic composition of the primary producer Thalassia testudinum also varied substantially with geographic location. However, compound-specific stable isotope analysis of amino acids (AA-CSIA) indicated that individuals in the nesting population with different bulk 15N values feed at the same trophic position. The combined results suggest that spatial differences in the isotopic composition of seagrass at the base of the food web, rather than differences in turtle foraging strategy, contribute to the isotopic variation in the nesting population. This study improves understanding of the foraging ecology of a highly dispersed and migratory species. © 2013 Inter-Research.

News Article | March 25, 2016

Researchers created a special lighting that can illuminate fishing nets. The add-on can help sea turtles avoid capture and lower the instance of fishermen accidentally catching them. The team from the University of Exeter believed that the green light emitting diodes (LEDs) can help sea turtles spot the mesh netting and avoid it without disturbing the fish. They tested their prototype off the Peru coast in a controlled experiment. The fishing nets not fitted with LEDs had 125 green turtles caught in the netting while the lit one only had 62. The numbers of guitarfish caught by the two nets were not affected by the illuminating add-ons. Each LED light cost about £1.40 ($2). With the illuminating fishing net, the research demonstrated that saving one turtle cost only £24 ($34). This amount can still be reduced if the technology will be used on a much larger scale. "This is very exciting because it is an example of something that can work in a small-scale fishery which for a number of reasons can be very difficult to work with," said Darwin Initiative research fellow Jeffrey Mangel. Mangel added that the sea turtle's eastern Pacific populations are one of the most vulnerable in the world. Lowering the sea turtle's bycatch could help in managing and recovering its population in the region. When the turtles get caught in the fishing nets or lines, it prevents them from reaching the surface for air and end up drowning. According to the Sea Turtle Conservancy, more than 250,000 sea turtles are captured, injured or killed accidentally by fishermen in the U.S. The baits often attract the sea turtles that they end up getting caught on the hooks used in catching fish. "Bycatch is a complex, global issue that threatens the sustainability and resilience of our fishing communities, economies and ocean ecosystems," said assistant NOAA administrator for fisheries, Eileen Sobeck. The experiment was published in the Marine Ecology Progress Series journal and conducted in northern Peru's Sechura Bay. The study was supported by the National Oceanic and Atmospheric Administration, the Lima-based not-for-profit organization ProDelphinus and the Darwin Initiative by the UK Government.

Ceriani S.A.,University of Central Florida | Roth J.D.,University of Manitoba | Evans D.R.,Sea Turtle Conservancy | Weishampel J.F.,University of Central Florida | Ehrhart L.M.,University of Central Florida
PLoS ONE | Year: 2012

In recent years, the use of intrinsic markers such as stable isotopes to link breeding and foraging grounds of migratory species has increased. Nevertheless, several assumptions still must be tested to interpret isotopic patterns found in the marine realm. We used a combination of satellite telemetry and stable isotope analysis to (i) identify key foraging grounds used by female loggerheads nesting in Florida and (ii) examine the relationship between stable isotope ratios and post-nesting migration destinations. We collected tissue samples for stable isotope analysis from 14 females equipped with satellite tags and an additional 57 untracked nesting females. Telemetry identified three post-nesting migratory pathways and associated non-breeding foraging grounds: (1) a seasonal continental shelf-constrained migratory pattern along the northeast U.S. coastline, (2) a non-breeding residency in southern foraging areas and (3) a residency in the waters adjacent to the breeding area. Isotopic variability in both δ13C and δ15N among individuals allowed identification of three distinct foraging aggregations. We used discriminant function analysis to examine how well δ13C and δ15N predict female post-nesting migration destination. The discriminant analysis classified correctly the foraging ground used for all but one individual and was used to predict putative feeding areas of untracked turtles. We provide the first documentation that the continental shelf of the Mid- and South Atlantic Bights are prime foraging areas for a large number (61%) of adult female loggerheads from the largest loggerhead nesting population in the western hemisphere and the second largest in the world. Our findings offer insights for future management efforts and suggest that this technique can be used to infer foraging strategies and residence areas in lieu of more expensive satellite telemetry, enabling sample sizes that are more representative at the population level. © 2012 Ceriani et al.

Ceriani S.A.,Florida Fish And Wildlife Conservation Commission | Ceriani S.A.,University of Central Florida | Roth J.D.,University of Manitoba | Tucker A.D.,Mote Marine Laboratory | And 5 more authors.
Marine Biology | Year: 2015

Migratory animals spend different periods of their lives in widely separated and ecologically different locations; their experiences from one activity/period/site (e.g., foraging) can dramatically affect their success during another (e.g., breeding). Carry-over effects reflect the influence of foraging quality on reproductive behaviors of migratory species, such as nesting loggerhead sea turtle (Caretta caretta), which vary greatly in body size and reproductive parameters. We investigated carry-over effects on 330 loggerheads nesting at the Archie Carr National Wildlife Refuge (Melbourne Beach, Florida), one of the largest aggregations in the Western Hemisphere, using telemetry, stable isotope analysis and reproductive parameters. We assigned foraging locations used during the non-breeding period with discriminant function analysis and determined the relative contributions to different foraging regions from 2007 to 2012. Foraging regions significantly influenced female body size and fecundity. Loggerheads foraging southeast of the nesting beach in the vicinity of the Bahamas and Florida Keys laid larger clutches and had a shorter breeding frequency. On average, 47 % (±3 % SE) of the females foraged year-round in this area, while 33 % (±4 % SE) resided on the Southwest Florida continental shelf south of Tampa Bay and 18 % (±2 % SE) undertook seasonal migrations and foraged north of Cape Hatteras, North Carolina. Relative contributions to the foraging areas did not change over the 6-year period. The northern foraging area consistently contributed the fewest females despite being the most productive oceanographic region suggesting a trade-off between foraging area productivity and distance to the nesting beach. We reaffirm that the isotopic approach can be used to interpret trends in abundance at nesting beaches and demographic parameters affecting those trends. Understanding geospatial linkages and relative importance of foraging areas is critical to fostering appropriate management and conservation strategies for migratory species. © 2015, Springer-Verlag Berlin Heidelberg (outside the USA).

D'Cruze N.,World Animal Protection formally the World Society for the Protection of Animals | Alcock R.,World Animal Protection formally the World Society for the Protection of Animals | Donnelly M.,Sea Turtle Conservancy
Journal of Agricultural and Environmental Ethics | Year: 2014

The Cayman Turtle Farm (CTF) is the only facility in the world that commercially produces green sea turtles (Chelonia mydas) for human consumption. The CTF has operated at a significant financial loss for much of its 45 years history and is maintained by substantial Cayman Island Government subsidies. These subsidies run into millions of Caymanian dollars and dwarf the funding allocated to The Caymanian Department of Environment to protect its unique biodiversity each year. We argue that it is time for the CTF to terminate its sea turtle ‘farming’ initiative. Supporters argue that the CTF helps to conserve green turtles by providing legal and sustainable turtle meat for local Caymanian consumption. Opponents maintain that farmed turtle meat cannot serve as an effective economically viable substitute, and that the facility potentially harms Caribbean green turtle populations by promoting turtle meat consumption, when other Caribbean nations increasingly prohibit this practice. The CTF’s records demonstrate that commercial production has come at the expense of tens of thousands of sea turtles. We question the ethics of sea turtle farming and argue that the CTF could better contribute to conservation if it transitioned into a rehabilitation, research and education facility (similar to the former sea turtle ranch Ferme Corail, now known as the Kélonia: Observatory of Marine Turtles). Recommended first steps include prohibiting the sale of sea turtle products to international tourists, engaging with stakeholders, and assessing the true scale of local consumer demand for green turtle meat. © 2014, The Author(s).

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