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Leatherback turtles (Dermochelys coriacea) have declined dramatically in the eastern Pacific Ocean (EP) in recent decades. Traditionally, population assessments have relied on the numbers of turtles on the beaches with the highest abundance of turtles (index beaches) and often disregarded the importance of nesting beaches with smaller, but still regular, numbers of nesting turtles (secondary beaches). We characterize leatherback nesting on secondary beaches throughout Pacific Costa Rica. Nesting distribution was significantly reduced since the 1990s and it currently appears to be constricted to the Santa Elena and Nicoya peninsulas. Over the past five years, nesting abundance on secondary beaches was low, ranging between 0.4 ± 0.5 and 5.3 ± 1.5 females and 3.8 ± 5.2 and 22.8 ± 10.8 nests per beach and per year. There was some exchange of turtles between beaches. The exchange rate (percentage of females that nested at least once on a different beach) ranged between 7% and 28%. While Caletas still registers multiple clutches that are laid by 1-2 females in some years, it may no longer qualify as a secondary beach due to the infrequent nature of nesting events registered recently and the total absence of nests in some of those years. Although nesting abundance is relatively low at secondary beaches, they host at least ~25% of total leatherback nesting abundance in Costa Rica. As the EP leatherback turtle declines, not only do the numbers of nesting turtles decrease but local extirpations are occurring on, previously categorized, secondary beaches. The critically low number of turtles at present may prevent recolonization of sites where they have been extirpated. [ABSTRACT FROM AUTHOR]

Eastern Pacific populations of the leatherback turtle ( Dermochelys coriacea ) have declined by over 90% during the past three decades. The decline is primarily attributed to human pressures, including unsustainable egg harvest, development on nesting beaches, and by-catch mortality. In particular, the effects of climate change may impose additional stresses upon already threatened leatherback populations. This study analyzes how the pelagic habitat of Eastern Pacific leatherbacks may be affected by climate change over the next century. This population adheres to a persistent migration pattern; following nesting at Playa Grande, Costa Rica, individuals move rapidly through equatorial currents and into foraging habitat within the oligotrophic South Pacific Gyre. Forty-six nesting females were fitted with satellite tags. Based on the turtle positions, ten environmental variables were sampled along the tracks. Presence/absence habitat models were created to determine the oceanographic characteristics of the preferred turtle habitat. Core pelagic habitat was characterized by relatively low sea surface temperatures and chlorophyll-a. Based on these habitat models, we predicted habitat change using output from the Geophysical Fluid Dynamics Laboratory prototype Earth System Model under the Special Report on Emissions Scenario A2 (business-as-usual). Although the model predicted both habitat losses and gains throughout the region, we estimated that overall the core pelagic habitat of the Eastern Pacific leatherback population will decline by approximately 15% within the next century. This habitat modification might increase pressure on a critically endangered population, possibly forcing distributional shifts, behavioral changes, or even extinction. [ABSTRACT FROM AUTHOR]

The article offers information on possible causes of mortality for adult leatherback turtles (Dermochelys coriacea). It states that a switching state-space model was applied to distinguish migratory and area-restricted search behaviors. It indicated a high spatial segregation between East Pacific(EP) and West Pacific(WP) nesting populations.They have high risk of exposure to many different fisheries and more susceptible to any temperature or prey changes that occur in response to climate change.

Leatherback turtles in the Pacific Ocean have declined precipitously in recent decades. One issue that may be contributing to the declines of leatherbacks and impairing their recovery is low clutch viability resulting from high embryonic mortality. Here, we examine trace metal concentrations in eggs and hatchlings from leatherbacks nesting on the Pacific coast of Costa Rica to assess whether contaminant levels reflect variation in the time over which females accumulated contaminants and whether variation in egg contaminant concentrations among nests influences clutch viability and hatchling characteristics. Eggs and hatchlings of Pacific leatherbacks contained detectable concentrations of a suite of essential and nonessential metals including Cu, Cd, Fe, Mn, Ni, and Zn, but variables that likely reflect a female's degree of temporal exposure to contaminants (relative age of female, body size, and remigration interval) explained little of the variation in egg metal concentrations. Concentrations of Cu, Cd, Fe, and Ni in Pacific leatherbacks were higher or toward the upper range of metal levels examined in sea turtle eggs elsewhere, but we did not find evidence linking egg contaminant levels with clutch success or hatchling size or body condition. These results represent the most comprehensive measures of trace metal concentrations from leatherback turtles in the eastern Pacific Ocean. [ABSTRACT FROM AUTHOR]

Abstract: Leatherback turtles ( Dermochelys coriacea ) are endangered, and declining population trends suggest that they are vulnerable to becoming extinct in the Pacific Ocean. Population recovery depends on strong conservation measures (e.g., nest protection, reduction of bycatch, and foraging habitat preservation) and on how fast leatherbacks grow and reach maturity, making the latter of grave concern. The research reported here marks the first time that several leatherback turtles have been maintained in captivity for nearly 2years, from hatchlings (6.31±0.13cm straight carapace length (SCL) and 46.0±1g) to juveniles (largest, 72.0cm SCL and 42.65kg). Leatherbacks maintained an average growth rate of 31.9±2.8cm year−1 in SCL throughout the study period. A length–mass relationship of the form, mass (kg)=0.000214⁎SCL (cm) 2.86, fitted our data and data from four other captive studies, 11 wild juveniles, and five studies of adult leatherbacks. Von Bertalanffy, Gompertz and logistic growth functions predicted age-at-maturity for leatherbacks of 16.1, 8.7 and 6.8years, respectively. The accuracy of these age-at-maturity estimates is discussed in the light of skeletochronological studies as well as estimates obtained from conservation and genetic studies. Our data, in combination with data from sightings, suggest that leatherbacks spend their early years (0 to 5years of age) growing in the warmer waters of the tropical and subtropical seas before entering cooler temperate waters. Information obtained from turtles incidentally captured in fisheries, supplemented with growth curve data, indicates that leatherbacks are vulnerable to entanglement or hooking in various pelagic gear types, such as drift gill nets and longline within 3years from nest emergence. Consequently, leatherbacks are exposed to threats from marine fisheries for >80% of their early life before carapace length characteristic of reproductive maturity is attained. [Copyright &y& Elsevier]

Satellite tracking data from female leatherback turtles reveal their migration routes in the eastern Pacific and demonstrate how oceanic currents shape their migration corridors, providing a biological basis for conservation strategies. [ABSTRACT FROM AUTHOR]

The article offers information regarding leatherback turtles or Dermochelys coriacia and issues related to their conservation. It states that the species of turtles which suffer fear of extinction in the Pacific ocean, however, has the potential to respond to conservation efforts more fast than hard-shelled cheloniid sea turtles. It also refers to various issues of the journal "Chelonian Conservation and Biology," that focused on the endangered species.

Proyecto Laúd coordinates the conservation activities for the leatherback turtle on 4 index beaches of the Mexican Pacific, combining efforts of different government and nongovernment institutions. With more than 20 years of tagging and conservation data, this project represents the most solid source of knowledge about the biology and ecology of the leatherback turtle in Mexico. Daily nesting track counts done from 1982 to 2004 showed a declining trend for the number of leatherback nests on the 4 index beaches of the Mexican Pacific (Mexiquillo, Tierra Colorada, Cahuitán, and Barra de la Cruz). The worst nesting season was 2002-2003, in which only 120 leatherback nests were recorded on the index beaches combined. The decline is attributed to a combination of extensive egg harvest on all Mexican Pacific beaches before conservation activities and high mortality of large adults in pelagic fisheries. A total of 5314 females were individually identified since 1982; the average remigration interval is 3 years. and there is evidence of interchange of females between some beaches. The female population has an average curved carapace length of 143.8 cm and an average clutch size of 62 eggs. The average estimated clutch frequency is 5.5 ± 1.9, with an average clutch interval of 9.7 ± 1.2 days. From 1982 to 2004 a total of 270,129 leatherback hatchlings were released to the wild population. This comparatively small number was not enough to offset the mortality of juveulles and adults offshore. This may explain the continuing population decline in spite of 20 years of protection activities. Currently, hope for the future of the population relies on the protection of at least 80% of the clutches laid on the priority beaches, the participation of local communities in conservation activities, and increased awareness of the leatherback's status among Mexican society. [ABSTRACT FROM AUTHOR]

A group of researchers, managers, and tribal leaders with extensive local knowledge from Papua New Guinea, Solomon Islands, Vanuatu, and Papua, Indonesia, provided new information on the status of leatherback nesting populations in the western Pacific Ocean. Twenty-eight nesting sites were identified, of which 21 were previously unknown or poorly described. Although data are still incomplete, we estimate a total of ca. 5000-9200 nests currently laid each year among these 28 sites, with approximately 75% of this nesting activity concentrated at 4 sites along the northwest coast (Bird's Head Peninsula) of Papua, Indonesia. Genetic analysis by using mitochondrial deoxyribonucleic acid sequences identified a total of 6 haplutypes among the 106 samples analyzed for Solomon Islands, Papua, and Papua New Guinea, including a unique common haplotype that is only found in these western Pacific populations. There was no significant difference in haplotype frequencies among these rookeries, which suggests that they represent a metapopulation composed of a single genetic stock. Further work is needed to define the demographic structure within this metapopulation. [ABSTRACT FROM AUTHOR]

The dramatic worldwide decline in populations of the leatherback turtle (Dermochelys coriacea) is largely due to the high mortality associated with their interaction with fisheries, so a reduction of this overlap is critical to their survival. The discovery of narrow migration corridors used by the leatherbacks in the Pacific Ocean raised the possibility of protecting the turtles by restricting fishing in these key areas. Here we use satellite tracking to show that there is no equivalent of these corridors in the North Atlantic Ocean, because the turtles disperse actively over the whole area. But we are able to identify a few ‘hot spots’ where leatherbacks meet fisheries and where conservation efforts should be focused. [ABSTRACT FROM AUTHOR]

The article presents a study which illustrates the reasons behind the increased population of leatherback turtle in the Atlantic Ocean than in the Pacific. The researchers had used the net primary productivity (NPP) in analysing the success rates of turtle population, their migratory patterns, and oceanographic variables. It was found out that turtle populations are regulated by the abundance of zooplankton. It was also discovered that local resources in the Atlantic is higher in the Pacific Ocean.

The article reports on the study of Scott Benson and colleagues which tracks the journey of leatherback sea turtle fishes nesting in Papua, Indonesia. The researchers expect that the turtles will migrate in eastern Pacific region, however, some of them headed towards South China Sea and North Pacific. It indicates that a female turtle headed towards Hawaii during winter and returns back to Oregon in spring. The researchers conclude that one particular turtle has traveled 20,558 kilometers over 647 days in various international borders.