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Plastic pollution has not raised much attention until the 2000s, despite being manufactured for about a century. It is now considered one of the most substantial environmental issues. Here we investigate the presence of plastic contamination in 34 stranded animals on the coast of French Guiana, South America. Here we present information highlighting the magnitude of plastic contamination in marine coastal and pelagic tropical marine vertebrates on the Equatorial Atlantic coast of South America. All four species studied here are protected and emblematic vertebrates of the region, with a fragile conservation status, including the olive ridley turtle Lepidochelys olivacea, the green turtle Chelonia mydas and the leatherback turtle Dermochelys coriacea, and a small cetacean, the Guiana dolphin Sotalia guianensis. Macroplastics (polypropylene, polyethylene, terephthalate, and polystyrene) were detected in four juvenile green turtles. Microplastics (polypropylene, polyethylene, terephthalate, polystyrene, nylon, acrylates, polycarbonates) were found in 13 individuals (two dolphins, six olive ridleys, four green turtles, and the leatherback turtle). The sampled species have different diets, distribution patterns, and ages, suggesting widespread plastic pollution. The study area is located far from the oceanic gyres. However, they are influenced by the North Brazilian Current, the Amazon River, and other rivers of the Guianas. [ABSTRACT FROM AUTHOR]

The leatherback sea turtle family Dermochelyidae has an extensive evolutionary history, though it is represented by only one living species today, Dermochelys coriacea. Dermochelyid fossils occur worldwide from upper Cretaceous to Pliocene marine strata. Herein described is the first occurrence of a sea turtle from the lowermost Pliocene Purisima Formation of northern California, a single carapacial non-ridge ossicle. The ossicle exhibits external morphological and internal structural characteristics (ossicle thickness, internal layering, serrate margins) that are comparable to both the extinct genus Psephophorus and to the extant genus Dermochelys. Identification of the ossicle as cf. Psephophorus is based on examination of its thickness, internal structure, surface textures and geochronological age. This paper reports the third occurrence of leatherback sea turtle fossils from the western coast of the United States.

Non‐crocodylian reptiles have hearts with a single ventricle, which is partially separated by a muscular ridge that provides some separation of blood flows. An exceptional situation exists in monitor lizards and pythons, where the ventricular left side generates a much higher systolic blood pressure than the right side, thus resembling mammals and birds. This functional division of the ventricle depends on a large muscular ridge and may relate to high metabolic demand. The large leatherback turtle (<1000 kg), with its extensive migrations and elevated body temperatures, may have similar adaptations. We report on the anatomy of the hearts of two leatherback turtles. One stranded in Ballum, Denmark in 2020, and was examined in detail, supplemented by observations and photos of an additional stranding specimen from Canada. The external morphology of the leatherback heart resembles that of other turtles, but it is large. We made morphometric measurements of the Ballum heart and created an interactive 3D model using high‐resolution MRI. The volume of the ventricle was 950 ml, from a turtle of 300 kg, which is proportionally almost twice as large as in other reptiles. The Ballum heart was compared to MRI scans of the hearts of a tortoise, a python, and a monitor lizard. Internally, the leatherback heart is typical of non‐crocodylian reptiles and did not contain the well‐developed septation found in pythons and monitor lizards. We conclude that if leatherback turtles have exceptional circulation needs, they are sustained with a relatively large but otherwise typical non‐crocodylian reptile heart. [ABSTRACT FROM AUTHOR]

After completing embryonic development, marine turtle hatchlings emerge from their subsurface nest, generally at night, and crawl to the ocean ('sea finding'). That response depends upon the ability of the turtles to discriminate between the brighter seaward versus a dimmer landward horizon, followed by a positive phototaxis. While the crawls of most marine turtle hatchlings are well oriented and straight, those of leatherback hatchlings are sometimes interrupted by bouts of circling. We conducted experiments comparing the orientation and crawling behaviour of leatherbacks to those of loggerhead hatchlings to determine why those differences occur. The two species did not differ in the light spectra attracting the hatchlings, but leatherback thresholds for detection and for intensity discrimination were significantly higher than those of loggerheads. At the nesting beach, loggerheads under full (bright) or new (darker) moon conditions crawled straight to the ocean; circling rarely occurred. Leatherback crawls under a full moon were indistinguishable from those of loggerheads, but during new moon trials, when horizon brightness differences approached leatherback intensity discrimination thresholds, circling increased significantly. We conclude that circling is probably used by leatherbacks to reinforce orientation decisions when horizon cues become more difficult to discern. Circling could be costly as it lengthens the crawl and increases exposure to terrestrial predators. We hypothesize that those costs persist because other visual adaptations affecting sensitivity enhance the ability of leatherbacks to detect prey, mates or favourable habitats in an open ocean environment. • We compared leatherback and loggerhead hatchlings' phototaxis responses. • Leatherbacks were less sensitive to wavelengths of 340–580 nm than loggerheads. • Under full moon, both species crawled directly from the nest to the sea. • Under new moon, leatherbacks were less accurate; loggerheads remained unchanged. • These responses may reflect sea-finding orientation–foraging efficiency trade-offs. [ABSTRACT FROM AUTHOR]

For many species, climate oscillations drove cycles of population contraction during cool glacial periods followed by expansion during interglacials. Some groups, however, show evidence of uniform and synchronous expansion, while others display differences in the timing and extent of demographic change. We compared demographic histories inferred from genetic data across marine turtle species to identify responses to postglacial warming shared across taxa and to examine drivers of past demographic change at the global scale. Using coalescent simulations and approximate Bayesian computation (ABC), we estimated demographic parameters, including the likelihood of past population expansion, from a mitochondrial data set encompassing 23 previously identified lineages from all seven marine turtle species. For lineages with a high posterior probability of expansion, we conducted a hierarchical ABC analysis to estimate the proportion of lineages expanding synchronously and the timing of synchronous expansion. We used Bayesian model averaging to identify variables associated with expansion and genetic diversity. Approximately 60% of extant marine turtle lineages showed evidence of expansion, with the rest mainly exhibiting patterns of genetic diversity most consistent with population stability. For lineages showing expansion, there was a strong signal of synchronous expansion after the Last Glacial Maximum. Expansion and genetic diversity were best explained by ocean basin and the degree of endemism for a given lineage. Geographic differences in sensitivity to climate change have implications for prioritizing conservation actions in marine turtles as well as for identifying areas of past demographic stability and potential resilience to future climate change for broadly distributed taxa. [ABSTRACT FROM AUTHOR]

Descriptions of the developmental stages of embryonic marine turtles are presented in the form of a dichotomous key supported by drawings to facilitate identifying stages of development in the field. The key emphasizes the sequential appearance or loss of external morphological structures that can be seen either with the unaided eye or with a X10 hand lens and a handheld light. Stages are placed in the context of normal beach temperatures to facilitate estimation of laying date, emergence date, and events that cause embryonic mortality. Measurements of embryos are presented to assist determining stage. [ABSTRACT FROM AUTHOR]

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This work describes the mycelial fungal diversity associated with leatherback sea turtle nests and eggs from Mayagüez-Añasco Bay Coast (MABC), Puerto Rico. Comparisons are made of conditions previous to leatherback nesting season, during leatherback nesting season, and during nest hatching season. Prior to Dermochelys coriacea nesting season, the fungal community along the MABC showed a normal distribution ( p = 0.098) by One-Way ANOVA. We found that Aspergillus was the most frequent genus (0.15), followed by Cladosporium (0.09) and Curvularia (0.08). At the time of oviposition, Penicillium was the most frequent isolate (0.15), followed by Cladosporium (0.11), Aspergillus (0.11), and Fusarium (0.07). No fungi were isolated from nesting leatherback's ovipositor samples. During hatching season, fungal diversity was evaluated from the sand of hatched nests and from failed eggs. Fusarium solani was the most frequent isolate (0.57) from hatched nest sand and was the only species isolated from the interior of failed eggs. A strong positive correlation was obtained between fungal abundance and the number of failed eggs in the nests ( r = 0.853, p < 0.001). This was the first attempt to study fungal diversity associated with D. coriacea nests and eggs in Puerto Rico. [ABSTRACT FROM AUTHOR]

Sea turtles are susceptible to environmental pollution, since many harmful effects have been reported for different chemicals over the last two decades. In this context, persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are of particular concern due to their endocrine-disrupting nature. The aims of this study were to provide additional baseline data on PCB and PBDE concentrations in eggs of Dermochelys coriacea; and to investigate whether any of the congeners could compromise reproductive success in this species. A total of 18 nests from different females were studied during the nesting season of 2008 at Reserva Pacuare Beach, in the Caribbean side of Costa Rica. Reproductive parameters (viability, fertility and hatching rates) were calculated for all nests and hatchling morphometrics were successfully measured in 8 of them. Two to three fresh eggs per nest were taken for contaminant study. Different congeners of POPs were purified and identified using gas chromatography (GC) coupled to an ion trap detector (GC-ITD MS/MS), as described below. Mean ± SD concentrations were calculated for POP congeners within each nest and clustering was also evaluated. Correlations were performed searching for potential relationships with reproductive parameters. POP levels were similar to those reported in French-Guiana populations and slightly lower than those associated to Florida populations. Sum of PBDEs showed a negative correlation to the hatching success, suggesting potential harmful effects of these contaminants on the reproduction of leatherbacks. [ABSTRACT FROM AUTHOR]

Leatherback turtles, Dermochelys coriacea , which have an irregular pink area on the crown of the head known as the pineal or ‘pink spot’, forage upon jellyfish in cool temperate waters along the western and eastern margins of the North Atlantic during the summer. Our study showed that the skeletal structures underlying the pink spot in juvenile and adult turtles are compatible with the idea of a pineal dosimeter function that would support recognition of environmental light stimuli. We interrogated an extensive turtle sightings database to elucidate the phenology of leatherback foraging during summer months around Great Britain and Ireland and compared the sightings with historical data for sea surface temperatures and day lengths to assess whether sea surface temperature or light periodicity/levels were likely abiotic triggers prompting foraging turtles to turn south and leave their feeding grounds at the end of the summer. We found that sea temperature was too variable and slow changing in the study area to be useful as a trigger and suggest that shortening of day lengths as the late summer equilux is approached provides a credible phenological cue, acting via the pineal, for leatherbacks to leave their foraging areas whether they are feeding close to Nova Scotia or Great Britain and Ireland. [ABSTRACT FROM AUTHOR]

We present the first study conducted in a wide spatio-temporal scale on marine turtles strandings ( N = 1,107) over a 12-year period (1999-2010) in Uruguay. Five species were recorded Chelonia mydas ( N = 643; 58.1 %), Caretta caretta ( N = 329; 29.7 %), Dermochelys coriacea ( N = 131; 11.8 %), Eretmochelys imbricata ( N = 3; 0.3 %), and Lepidochelys olivacea ( N = 1; 0.1 %). The first three species stranded throughout the Uruguayan coast, but differences in distribution patterns were detected among species. Although occurring year round, stranding records show a clear seasonal pattern with variation in monthly distribution among species, but with a peak of records in austral summer. Strandings provide indirect evidence of threats to marine turtles in Uruguayan and surrounding waters, particularly fisheries and marine debris. Our results demonstrate that Uruguayan coastal waters likely serve as a foraging or development area for at least three endangered marine turtle species in temperate waters. [ABSTRACT FROM AUTHOR]

The leatherback turtle regularly undertakes deep dives and has been recorded attaining depths in excess of 1200 m. Its trachea is an almost solid, elliptical-section tube of uncalcified hyaline cartilage with minimal connective tissue between successive rings. The structure appears to be advantageous for diving and perfectly designed for withstanding repeated collapse and reinflation. This study applies Boyle's law to the respiratory system (lungs, trachea and larynx) and estimates the changes in tracheal volume during a dive. These changes are subsequently compared with the results predicted by a corresponding finite element (FE) structural model, itself based on laboratory studies of the trachea of an adult turtle. Boyle's law predicts that the lungs will collapse first during the initial stages of a dive with tracheal compression beginning at much deeper depths after complete air mass expulsion from the lungs. The FE model reproduces the changes extremely well (agreeing closely with Boyle's law estimations) and provides visual representation of the deformed tracheal luminal area. Initially, the trachea compresses both ventrally and dorsally before levelling ventrally. Bulges are subsequently formed laterally and become more pronounced at deeper depths. The geometric configuration of the tracheal structure confers both homogeneity and strength upon it, which makes it extremely well suited for enduring repeated collapse and re-expansion. The structure actually promotes collapse and is an adaptation to the turtle's natural environment in which large numbers of deep dives are performed annually. [ABSTRACT FROM AUTHOR]

A major interest has recently emerged in understanding how telomere shortening, mechanism triggering cell senescence, is linked to organism ageing and life history traits in wild species. However, the links between telomere length and key history traits such as reproductive performances have received little attention and remain unclear to date. The leatherback turtle Dermochelys coriacea is a long-lived species showing rapid growth at early stages of life, one of the highest reproductive outputs observed in vertebrates and a dichotomised reproductive pattern related to migrations lasting 2 or 3 years, supposedly associated with different environmental conditions. Here we tested the prediction of blood telomere shortening with age in this species and investigated the relationship between blood telomere length and reproductive performances in leatherback turtles nesting in French Guiana. We found that blood telomere length did not differ between hatchlings and adults. The absence of blood telomere shortening with age may be related to an early high telomerase activity. This telomere-restoring enzyme was formerly suggested to be involved in preventing early telomere attrition in early fastgrowing and long-lived species, including squamate reptiles. We found that within one nesting cycle, adult females having performed shorter migrations prior to the considered nesting season had shorter blood telomeres and lower reproductive output. We propose that shorter blood telomeres may result from higher oxidative stress in individuals breeding more frequently (i.e., higher costs of reproduction) and/or restoring more quickly their body reserves in cooler feeding areas during preceding migration (i.e., higher foraging costs). This first study on telomeres in the giant leatherback turtle suggests that blood telomere length predicts not only survival chances, but also reproductive performances. Telomeres may therefore be a promising new tool to evaluate individual reproductive quality which could be useful in such species of conservation concern. [ABSTRACT FROM AUTHOR]

Florida (United States) beaches serve as globally important nesting habitat for protected species of sea turtles. Following coastal development, portions of this habitat have become inaccessible to nesting sea turtles due to coastal armoring and other barriers. To assess nesting habitat quality, we randomly selected beaches totaling 80.45 km in each of four regions of Florida (northeast, southeast, northwest, and southwest) and surveyed them for potential barriers to nesting during the period of April 2001 to May 2002 (total surveyed coastline 5 321.8 km). Potential barriers to nesting were found in 78 forms on sampled beaches, including seawalls, revetments, sand bags or tubes, sand fences, access structures, recreational equipment, and buildings. We determined the position and extent of structures using a differential global positioning system. Surveyed beaches made up 24.5% of Florida's sandy coastline and were sampled to be regionally representative. In an assessment summed for all regions, potential barriers to nesting occupied 18.0% of the total surveyed beach length. The region with the greatest extent of potential barriers was southeast (23.8%), followed by southwest (21.7%), northwest (14.1%), and northeast (12.3%). Seawalls were the most common potential barriers in all but the northwest region, where sand fences were most common. Our measurements did not include structures that were hidden from view by sand or other structures. Following coastal effects from four major hurricanes that made landfall in 2004, we resurveyed 16 km of beach in each region (total 5 64 km). We recorded a net reduction of sand fencing in northeast and northwest Florida and a net reduction of revetment rocks in the southwest region due to covering by sand. However, the linear extent of barriers increased in northeast and southwest due to seawall construction and additional sand fencing. [ABSTRACT FROM AUTHOR]

Graham, T. R., Harvey, J. T., Benson, S. R., Renfree, J. S., and Demer, D. A. 2010. The acoustic identification and enumeration of scyphozoan jellyfish, prey for leatherback sea turtles (Dermochelys coriacea), off central California. – ICES Journal of Marine Science, 67: 1739–1748.Acoustic-sampling techniques were developed to estimate the abundance and distribution of scyphozoan jellyfish, prey for leatherback turtles foraging off central California. Acoustic data were analysed from regions where jellyfish were present or absent from corresponding net tows. Empirical data on bell-diameter distribution (mean 26.2 cm; s.d. 10.6) were used to estimate target strength (TS; dB re 1 m2) at 18, 38, 70, 120, and 200 kHz using a distorted-wave Born approximation scattering model. TS measurements of in situ animals at 38 and 200 kHz averaged −63.9 and −70.5 dB, compared with the model estimates of −54.9 and −64.0 dB, respectively. The model estimates of TS at 18, 70, and 120 kHz were −53.9, −59.9, and −61.8 dB, respectively. Using these TS estimates, an algorithm was developed to extract jellyfish echoes from total acoustic backscatter. Echo-integration methods applied to regions where net catches contained jellyfish resulted in an estimate of mean numerical abundance of 3217 jellyfish (s.d. 2276) with a mean density of 251 522 jellyfish nautical mile−2 (s.d. 57 504) and a mean concentration of 0.003 jellyfish m−3 (s.d. 0.002). The novel methods developed will help characterize prey resources for leatherback turtles off central California. [ABSTRACT FROM PUBLISHER]

The threat status of New Zealand's reptiles was re-evaluated, using revised New Zealand Threat Classification System criteria. The resulting list included 109 known taxa and undescribed entities—an increase of 11 since the 2005 listing. Two species were listed as Extinct; 17 taxa were listed as Threatened, including six as Nationally Critical, three as Nationally Endangered, and eight as Nationally Vulnerable; 51 taxa were listed as At Risk, including 10 Naturally Uncommon, 11 Relict, 3 Recovering, and 27 Declining; eight taxa were listed as Data Deficient; five visiting marine species were listed as Vagrant, and two as Migrant; 23 taxa were considered Not Threatened; and there was one Introduced and Naturalised species. The six taxa assessed as being at greatest risk of extinction (Nationally Critical) were all South Island skinks. Five taxa had improved in threat status since 2005 as a result of conservation management action. Two taxa had worsened in threat status due to potential threats from rabbit-driven predator irruptions plus the new threat of dairy conversion destroying habitat. The threat status of a further 24 taxa changed as a result of improved knowledge or a change in the criteria and/or categories since 2005. [ABSTRACT FROM AUTHOR]

Adult leatherbacks are large animals (300-500kg), overlapping in size with marine pinniped and cetacean species. Unlike marine mammals, they start their aquatic life as 40-50g hatchlings, so undergo a 10,000-fold increase in body mass during independent existence. Hatchlings are limited to the tropics and near-surface water. Adults, obligate predators on gelatinous plankton, encounter cold water at depth (<1 280 m) or high latitude and are gigantotherms that maintain elevated core body temperatures in cold water. This study shows that there are great ontogenetic changes in tracheal structure related to diving and exposure to cold. Hatchling leatherbacks have a conventional reptilian tracheal structure with circular cartilaginous rings interspersed with extensive connective tissue. The adult trachea is an almost continuous ellipsoidal cartilaginous tube composed of interlocking plates, and will collapse easily in the upper part of the water column during dives, thus avoiding pressure-related structural and physiological problems. It is lined with an extensive, dense erectile vascular plexus that will warm and humidify cold inspired air and possibly retain heat on expiration. A sub-luminal lymphatic plexus is also present. Mammals and birds have independently evolved nasal turbinates to fulfil such a respiratory thermocontrol function; for them, turbinates are regarded as diagnostic of endothermy. This is the first demonstration of a turbinate equivalent in a living reptile. [ABSTRACT FROM AUTHOR]

Industrial logging is expanding rapidly in Central African rainforests. We suggest that logging operations in this region pose an indirect threat to nesting marine turtles, especially the Critically Endangered leatherback turtle Dermochelys coriacea. This occurs because some logs are being lost or abandoned during downriver transport to coastal timber yards; the lost logs float out to sea and then often wash ashore, where they accumulate on beaches used by nesting turtles. We used a light aircraft to survey logs along the entire coastline of Gabon, and also studied the impacts of logs at Pongara Beach, one of the world's most important turtle nesting areas, during the 2002-2003 and 2003-2004 breeding seasons. Nearly 11,000 lost logs were counted along Gabon's beaches, with an estimated commercial value of USD 11.1 million. Logs were unevenly distributed along the coast, reaching a peak density of 247 logs km-1. At Pongara, logs blocked 30.5% of the beach. These logs had a number of negative effects on marine turtles, causing 8-14% of all nesting attempts (n = 2,163) to be aborted or disrupted. Initiatives to remove lost logs and driftwood from critical nesting beaches may be the most effective means to reduce their deleterious impacts on threatened marine turtles. [ABSTRACT FROM AUTHOR]

Abstract: The study of turtle population genetics has come a long way in the past few decades. In the early 1990s, technologies such as polymerase chain reaction (PCR) and automated DNA sequencing spearheaded a boom in molecular ecology. Microsatellite and mitochondrial DNA haplotype markers became the methods of choice for many turtle studies. Today, the rate of research continues unabated. The emergence of new methods, approaches and ideas means exciting prospects for the molecular ecology of marine turtles. A review of genetic markers that have been used for turtle research provides a starting point for those breaking into this area for the first time. Here current molecular techniques are discussed, but upcoming new ideas and methods are also highlighted. A recently proposed hypothesis to explain the polyandrous behaviour of female turtles means a fresh direction for multiple paternity studies. A new statistical approach (individual-based analysis) offers future studies analytical methods other than F-statistics, and an alternative means to test male-biased gene flow. Paternity analysis now enables robust reconstruction of male genotypes from their offspring, elucidating the genetics of adult male turtles without collecting them in the field. With whole genome amplification (WGA) limited DNA samples can be amplified for long-term storage, large-scale analyses and easy exchange between laboratories. New genetic markers are essential for future progress, and breakthrough DNA sequencing technologies will facilitate marker discovery. The next-generation sequencing methods also means that the new ‘-omics’ techniques of genomics and transcriptomics may in the future be applicable to marine turtle research. [Copyright &y& Elsevier]

Objective The Leatherback sea turtle is the largest extant reptile and the sole member of the family Dermochelyidae. Here, the eye of this critically endangered marine turtle was investigated to determine the anatomy, optics, and optical sensitivity. Animals studied Three Leatherback sea turtles, Dermochelys coriacea. Results The eye is small in proportion to body size of the adult compared to other vertebrates, with prominence of the retractor bulbi and pyramidalis muscles. The nictitans shows extensive folding of the bulbar conjunctiva as an apparent mechanism to increase the surface area for mucus secretion. The intraocular anatomy is consistent with an eye adapted to aquatic vision with minimal curvature of the cornea, a near-spherical lens, deep ciliary cleft and highly vascularized ciliary body. The optical sensitivity, a measure of the sensitivity to light of a given optical system, is higher than in other marine turtles studied but lower than those found in teleost fish that share a habitat with the Leatherback sea turtle. Conclusions The Leatherback sea turtle shows ocular features that are characteristic of Chelonians with similarities to aquatic mammals. The calculated optical sensitivity suggests that compared to pelagic fishes, for instance, the Leatherback sea turtle eye is not particularly well adapted for vision in dim light even though this species is known to venture into deep, dark waters, and might feed at night. [ABSTRACT FROM AUTHOR]

Abstract: Changes in activity related oxygen consumption were measured in leatherback and olive ridley sea turtle hatchlings over their first month after emergence from the nest. Leatherbacks emerged with 75–90 KJ of energy in the residual yolk for growth and activity whereas olive ridleys emerged with 45 KJ. In leatherbacks (n =8), resting mass-specific oxygen consumption rates decreased by 53% over the first post–hatching month (0.34+0.03 mL O2 h−1 g−1 to 0.16+0.01 mL O2 h−1 g−1, respectively), while for ridleys (n =8) the fall was 35% (0.20+0.03 mL O2 h−1 g−1 to 0.13+0.01 mL O2 h−1 g−1, respectively). Olive ridley factorial aerobic scope doubled (1.93+0.30 to 3.97+0.51) over the first month but there was no significant increase in leatherback factorial aerobic scope (1.39+0.21 to 1.60+0.13). Leatherback hatchlings gained on average 20% initial body mass (7.68+1.66 g) over the first week, with 70 to 80% of this increase due to water accumulation. Olive ridleys gained 14% (1.83+0.16 g) in initial mass over the first week of age. We propose that the differences in aerobic scope and energy reserves are related to differences in early life ecological stratagems of these species. [Copyright &y& Elsevier]

Chiriqui Beach, in the Comarca Ngöbe-Buglé on the Caribbean coast of Panama, is the most important nesting beach for leatherback turtles (Dermochelys coriacea) in Caribbean Central America. Beach surveys during the 2003 and 2004 nesting seasons documented 3077 leatherback nests in one season and a minimum of 234 individual leatherbacks. Monitoring of nest fate revealed that predation by dogs represents the greatest human-related survival threat to leatherbacks at Chiriqui Beach, although the killing of leatherbacks from the same nesting population on beaches near the Panama-Costa Rica border also is of concern. [ABSTRACT FROM AUTHOR]

Hatching success for leatherback turtles (Dermochelys coriacea) was low at 4 important nesting beaches in Papua, with high rates of tidal inundation, pig predation, and possible temperature effects. Better protection from pigs and possible nest relocation may be needed to improve hatching success for leather- backs. [ABSTRACT FROM AUTHOR]

Nine leatherback turtles (Dermochelys coriacea) were tracked for 111-695 days via satellite telemetry from one of the largest remaining western Pacific leatherback turtle nesting beaches, Jamursba-Medi, Papua, Indonesia. The turtles moved into tropical waters of the Philippines and Malaysia, into the Sea of Japan, and across the equatorial Pacific to temperate waters off North America. This study provides the first record of a Irans. Pacific migration by a leatherback turtle. [ABSTRACT FROM AUTHOR]

Leatherbacknesting along the Atlantic coast of Africa extends from Mauritania in the north to Angola in the south, with a globally important nesting concentration located in Gabon in Central Africa. Provisional estimates of nesting numbers from Gabon indicate that this nesting population may he among the largest in the world. [ABSTRACT FROM AUTHOR]

Leatherback turtle (Dermochelys coriacea) nesting activity was monitored, individual movements via flipper tag recoveries and satellite telemetry were determined, and illegal egg collection was quantified at Tortnguero, Costa Rica from 1995 to 2006. Annual nest deposition was estimated at 199-1,623 nests per year; a Bayesian regression model suggests that leatherback nesting decreased by 67.8% between 1995 and 2006. Tag recaptures from fisheries bycatch and strandings have been reported from Cuba, Nicaragua. and the United States. Two leatherbacks were followed with satellite telemetry; 1 swam to Cuba and I moved into the northwest Atlantic Ocean. Minimum rates for illegal egg collection from 2000 to 2005 were estimated at 13.0%-21.59%. [ABSTRACT FROM AUTHOR]

Playa Langosta is 1 of 3 nesting beaches in Parque Nacional Marino Las Baulas de Guanacaste, and is 1.3-km long. The 3 beaches (Langosta, Grande, and Ventanas) represent over 6 km of leatherback (Dermochelys coriacea) nesting. The use of passive integrated transponder (PIT) tags allowed us to identify each leatherback that nested at Playa Langosta. A total of 252 individual leatherbacks nested between the 1999-2000 and 2003-2004 nesting seasons. Of these, 63% (n = 158) were new turtles (untagged before), and 50% (n = 79) of the new turtles were originally PIT tagged on Playa Langosta. The majority of these turtles 54%) nested only on Playa Langosta, whereas a slightly smaller percentage (46%) nested at both Playa Grande and Playa Langosta. We recorded 904 encounters and 792 nests at Playa Langosta for the 5 nesting seasons of this study. Leatherbacks nesting at Playa Langosta ranged in curved carapace length from 125 to 164 cm and in curved carapace width, from 90 to 116 cm. Average internesting period was 9.6 days. For the first 4 seasons, data from excavated nests showed a decrease in percentage of hatching success from 68.9% to 30.4% in natural nesting conditions. A dramatic decline to emergence success from 57.2% to 9.3% occurred for these respective seasons. For the last 3 seasons, the hatching success of leatherback turtles in relocated nests was 52.4%, 18.9%, and 51.4%. [ABSTRACT FROM AUTHOR]

Field research was conducted, from 1990 In 2004, at Gaudoca Beach (9°59.972'N. 82°60.530'W). located within the Gandoca-Manzanillo National Wildlife Refuge at the southernmost extreme of the Caribbean coast of Costa Rica. Nightly patrols of the 8.85-km nesting beach were undertaken annually from the second week of February through the last week of July, and pertinent information regarding the nesting process was recorded. An estimated 90% of all nesting females were documented and uniquely tagged; these 2751 females deposited 8766 nests (believed to he a complete count). Averaged over the 15-year study period. 12.5% of all nests were left unaltered in situ; 12.9% were left in situ, with tracks camouflaged by beach patrollers; 33.9% were relocated to lower risk zones on the beach; and 25.4% were relocated to beach hatcheries. Poaching, which had once claimed nearly 100% of all eggs laid, averaged 15.5% annually during the study period, demonstrating a clearly declining trend, attributable to the presence of beach patrollers, policies associated with the wildlife refuge, and changing attitudes within proximal communities. A comparison of tag registries indicates an interchange of gravid females among nesting beaches both within Costa Rica and internationally with Panama and Colombia. The interchange reinforces the importance of joint efforts to address primary threats, including beach erosion, egg poaching, direct harvest of adults for meat (especially in Panama), and coastal development. The population is statistically stable but shows a steadily declining trend to the number of nests laid since 2000. [ABSTRACT FROM AUTHOR]

From 1985 to 1999, data were gathered opportunistically on the bycatch of 33 leatherback turtles in coastal Peru, and from 2000 to 2003, a dockside observer program provided data on an additional 133 leatherbacks caught in the coastal gilluet and longline fisheries targeting mahi mahi, sharks, and rays. These data stress the need for programs to monitor bycatch in artisanal fisheries. enforce regulations prohibiting sea turtle capture, and increase the environmental awareness of fishermen. [ABSTRACT FROM AUTHOR]

Suriname beaches support a major nesting colony of leatherback turtles. During the 1999-2005 nesting seasons, we collected data on nesting ecology and identified individual turtles that nested at Babunsanti (Galibi Nature Reserve), Samsambo, Kolukumbo, and Matapica. We observed 8462 leatherback females, 6933 of which we PlT-tagged. The remaining 1529 females carried PIT tags of a non-Surinamese origin. Because complete coverage of all nesting beaches was not possible over the study period, estimations of minimum annual nesting colony size were made, which ranged from 1545 to 5500 females in Suriname alone. Of the 7394 turtles observed during 1999-2004, 14.8% were seen renesting by 2005. Annual mean internesting period ranged between 9.4 ± 1.0 to 9.6 ± 1.0 days. Annual mean observed clutch frequency was between 1.6 ± 1.0 to 3.1 ± 1.4 and annual minimum estimated clutch frequency between 4.1 ± 1.6 to 4.9 ± 1.8 clutches. Annual mean standard curved carapace length ranged from 154.1 ± 6.7 to 155.6 ± 6.7 cm, and annual mean clutch size ranged from 80.8 ± 18.3 to 88.2 ± 19.5 yolked eggs. Annual average hatch success (including nests with zero batching) ranged from 10.6% ± 16.4 to 25.8% ± 24.4 at Babunsanti, and from 52.7% ± 29.7 to 56.0% ± 30.8 at Matapica. Remigrants and non-Surioamese turtles were, on average, larger than new females, and remigrants had a higher clutch frequency. In 6 years, the annual proportion of newly tagged females decreased from 89.9% to 40.5% and that of remigrants increased from 0% to 45.6%. However, the annual proportion of turtles with a nun-Surinamese PIT tag (10.1% to 17.6%) was relatively stable. Combined with the moderate frequency of intra- and interseasonal nesting exchange between regional beaches, this indicates that although the Suriname/French Guiana leatherbacks form a single rookery, individual females show strong nesting fidelity to one side of the Marowijne Estuary. [ABSTRACT FROM AUTHOR]

1. Pacific leatherback turtle Dermochelys coriacea populations have been declining precipitously. It has been suggested that fishery-associated mortality is the leading factor causing the decline; however, the sensitivity of leatherbacks to climate variability relative to their population ecology is unknown. 2. We investigated the effects of interannual climate variability, as governed by the El Niño Southern Oscillation (ENSO), on leatherback nesting ecology. We used equatorial Pacific sea surface temperature (SST) anomaly data over various time scales derived from both moored buoys and remote satellites as signals of ENSO. We then incorporated these data into a remigration probability model for the largest nesting population of eastern Pacific leatherbacks at Parque Nacional Marino Las Baulas (PNMB), Costa Rica. 3. Our results showed that nesting females of PNMB exhibited a strong sensitivity to ENSO, as reflected in their nesting remigration probabilities. Cool La Niña events corresponded with a higher remigration probability and warm El Niño events corresponded with a lower remigration probability. 4. We suggest that productivity transitions at leatherback foraging areas in the eastern equatorial and south-eastern Pacific in response to El Niño/La Niña events result in variable remigration intervals and thus variable annual egg production. This phenomenon may render the eastern Pacific leatherback population more vulnerable to anthropogenic mortality than other populations. 5. Synthesis and applications. Physical indices of environmental variation can be used to estimate the probability of leatherbacks remigrating to nest at PNMB. This type of modelling approach can be extremely useful for understanding the effects of climatic variation on the population dynamics of sea turtles. Our remigration probability model can be applied to any monitored sea turtle nesting population where nesting site fidelity and beach monitoring coverage remains high. This modelling approach can help nesting beach monitoring programmes forecast remigrant numbers based on prior climate data, and can further quantify anthropogenic mortality by validating survival estimates. [ABSTRACT FROM AUTHOR]

Abstract: The pattern and control of respiration is virtually unknown in hatchling sea turtles. Using incubator-raised turtles, we measured oxygen consumption, frequency, tidal volume, and minute volume for leatherback (Dermochelys coriacea) and olive ridley (Lepidochelys olivacea) turtle hatchlings for the first six days after pipping. In addition, we tested the hatchlings'' response to hypercapnic, hyperoxic, and hypoxic challenges over this time period. Hatchling sea turtles generally showed resting ventilation characteristics that are similar to those of adults: a single breath followed by a long respiratory pause, slow frequency, and high metabolic rate. With hypercapnic challenge, both species responded primarily by elevating respiratory frequency via a decrease in the non-ventilatory period. Leatherback resting tidal volume increased with age but otherwise, neither species'' resting respiratory pattern nor response to gas challenge changed significantly over the first few days after hatching. At the time of nest emergence, sea turtles have achieved a respiratory pattern that is similar to that of actively diving adults. [Copyright &y& Elsevier]

Some marine species have been shown to target foraging at particular hotspots of high prey abundance. However, we show here that in the year after a nesting season, female leatherback turtles (Dermochelys coriacea) in the Atlantic generally spend relatively little time in fixed hotspots, especially those with a surface signature revealed in satellite imagery, but rather tend to have a pattern of near continuous traveling. Associated with this traveling, distinct changes in dive behavior indicate that turtles constantly fine tune their foraging behavior and diel activity patterns in association with local conditions. Switches between nocturnal vs. diurnal activity are rare in the animal kingdom but may be essential for survival on a diet of gelatinous zooplankton where patches of high prey availability are rare. These results indicate that in their first year after nesting, leatherback turtles do not fit the general model of migration where responses to resources are suppressed during transit. However, their behavior may be different in their sabbatical years away from nesting beaches. Our results highlight the importance of whole-ocean fishing gear regulations to minimize turtle bycatch. [ABSTRACT FROM AUTHOR]

Oceanographic sampling is often limited to local and temporally concise assessments of complex, transient, and widespread phenomena. However, long-lived, migratory pelagic vertebrates such as leatherback turtles ( Dermochelys coriacea, Vandelli 1761) can provide important integrated information about broad-scale oceanographic processes. Therefore, the present study analyzed stable carbon and nitrogen isotope ratios (δ13C and δ15N) of egg yolk and red blood cells from nesting leatherback populations from Costa Rica in the eastern Pacific in 2003–2004 and 2004–2005 and from St. Croix in the North Atlantic in 2004 and 2005 to establish differences between nutrient sourcing and its influence on higher trophic level consumers in both ocean basins. Whereas δ13C signatures were similar between Costa Rica (−19.1±0.7‰) and St. Croix (−19.4±1.0‰) leatherbacks, reflecting the pelagic foraging strategy of the species, Costa Rica leatherback δ15N signatures (15.4±1.8‰) were significantly enriched relative to St. Croix leatherback δ15N signatures (9.8±1.5‰). This δ15N difference likely reflects inter-basin differences in nitrogen cycling regimes and their influence on primary productivity being transferred through several trophic levels. Thus, high-order marine consumer movements, habitat preferences, and stable isotope signatures can be combined with ocean sampling to elucidate interactions between oceanographic processes and marine megafauna. [ABSTRACT FROM AUTHOR]

To assess the impact of nest covering on a leatherback turtle Dermochelys coriacea nesting beach in French Guiana, we used field study data and a modelling approach. Field results showed that the covering of a pre-existing nest by a new one causes the destruction of the older nest under some conditions of time and covering area, and almost always causes the destruction of the new nest. We then used field results to parameterize a theoretical model of the nesting beach. This allowed us to obtain a ‘critical carrying capacity for the beach’: the number of nests deposited for which the number of successful nests is maximum; when this number increases, the number of successful nests decreases. With these results, we then concluded that density-dependent nest destruction plays a role in the functioning of the nesting beach. These results are essential for our understanding of nest-site selection at the scale of the beach and its consequences. [ABSTRACT FROM AUTHOR]

Leatherback turtles (Dermochelys coriacea) are critically endangered in the eastern and western Pacific Ocean. Here, I estimate the magnitude of two likely causes of their decline: (i) bycatch by longline fishing vessels and (ii) coastal sources of mortality. I calculate point estimates of longline bycatch based on turtle catch rates from the US Hawaii-based fleet and effort data for the international Pacific longline fleet. I estimate the intrinsic growth rate of the population and the magnitude of coastal mortality by fitting a simple logistic model. In the western and central Pacific, coastal sources lead to a 13% annual mortality rate, compared with a point estimate of 12% from longlining. In the eastern Pacific, coastal sources account for a 28% annual mortality rate, compared with a point estimate of only 5% from longlining. A Bayesian risk assessment reveals the importance of reducing coastal sources of mortality, as well as longline bycatch, if the populations are to avoid extinction. International efforts to protect the leatherback should expand beyond focusing solely on longline bycatch and should attempt to reduce coastal harvest of adult females and eggs, as well as reduce bycatch by inshore gears such as gillnets. [ABSTRACT FROM AUTHOR]

The biology of the endangered leatherback turtle ( Dermochelys coriacea) at sea is poorly understood. As research has been almost exclusively limited to studies of nesting females, the movements of male turtles and the timing and location of mating activity have remained unknown. We report on the first deployments of satellite tags on male leatherbacks. Male migration to and residency in waters adjacent low-latitude nesting beaches in the western Atlantic suggest that this is where mating occurs, and return migration to these areas reveals male fidelity for breeding sites. Rate of travel decreased markedly after arriving in coastal breeding areas, where males remained for up to 96 days before assuming northward migrations. The initiation of these northward migrations coincided with peak nesting activity in adjacent nesting colonies. Data from satellite-linked time-depth recorders attached to two males revealed diel dive patterns in breeding areas and marked differences in diving behaviour between migratory and breeding periods in one turtle. When male turtles were in waters adjacent nesting colonies, their movements differed from those reported for nesting females, with females ranging farther from shore. Our results suggest that male leatherbacks may be vulnerable to entanglement in coastal fishing gear in waters adjacent nesting beaches. [ABSTRACT FROM AUTHOR]

Leatherback sea turtles (Dermochelys coriacea) nesting in French Guiana have been the focus of a long-term monitoring and metal flipper-tagging program and were subjected to a double-tagging experiment starting in 1994. We developed a new method to estimate the rate of tag loss based on the number of days at liberty after tagging, using maximum likelihood function fitting. Metal tag loss in leatherback sea turtles is characterized by a high rate of loss just after tagging (>30% of turtles lose at least 1 tag within a year) and is followed by higher retention over a longer time period. Using additional data from permanent internal tags that were subsequently applied to turtles in French Guiana, we have shown that the rate of loss of the second metal tag was higher than that of the first metal tag. More accurate estimates of tag loss rates are essential for correctly gene rating demographic parameters from Capture-Mark-Recapture (CMR) analyses. We have developed a software package to facilitate the use of these models by others researchers in estimating tag loss. [ABSTRACT FROM AUTHOR]

The possibility of nest site fidelity of leatherback turtles, Dermochelys coriacea, raises concerns about the merit of translocating poorly located clutches to a safe hatchery. Specifically, if some females habitually nest in areas where the probability of egg survival is low because of tidal inundation, nest relocation may inadvertently select for turtles that make poor nest site selections. We investigate the nest site fidelity of leatherbacks by studying consecutive nest site selections by leatherbacks at Playa Grande, Costa Rica, from 1993 to 2001. Along the ocean-to-vegetation axis, consecutive nest placements were independent (G42=4.737, P=0.315). Regardless of previous zone choices, leatherbacks typically nested in the open beach above the high tide line and away from vegetation. Thus, concerns about translocation of poorly located nests are unfounded. Along the coastal axis, however, an independence model was rejected (G362=145.179, P < 0.001). The log-linear model-based analysis we developed and applied indicated that the pattern of dependence in nest site locations is more consistent with a hypothesis of spatial proximity in which leatherbacks simply nest close to the site of the previous nest than it is with a hypothesis of intrinsic fidelity to a specific location on the beach. Our model-based approach is suitable for other settings where longitudinal nesting data are available. [Copyright &y& Elsevier]

We determined individual nest placement patterns for female leatherbacks nesting at Awa:la-Ya:lima:po, French Guiana, by measuring distance from the nest to several landscape features, such as the highest spring tide line (HSTL) and the vegetation line. Distance from the nest to the HSTL differed significantly between females, indicating the existence of individual nesting patterns. There was a significant repeatability of nest site choice relative to the HSTL, indicating that females showed within-individual consistency in their nest placement. Despite individual preferences, there was much within-individual variation and a lack of predictability in the nesting patterns; that is, the locations of subsequent nests could not be predicted based on knowledge of previous nest choices, indicating a certain degree of scatter. The significant repeatability suggests that nest choice behaviour in female leatherbacks is heritable and may show the potential for further evolution. We tested sea-finding ability of hatchlings, a potential consequence of nest site choice, in Matapica, Suriname, by using orientation arenas to quantify the strength and direction of travel after emergence. The orientation tests showed that hatchlings were unable to move seaward in vegetated arenas, providing evidence that vegetation acts as a strong selective pressure driving nest placement seaward. It appears that leatherbacks have adopted a regional rather than a local optimum for nest placement patterns, possibly resulting from their weak beach fidelity and the frequent erosion and destruction of their nesting beaches. We discuss the evolutionary and conservation implications for this species in the context of current environmental changes. [Copyright &y& Elsevier]

We used Satellite Relay Data Loggers to obtain the first dive profiles for critically endangered leatherback turtles outside the nesting season. As individuals moved from the Caribbean out into the Atlantic, key aspects of their diving behaviour changed markedly, in line with theoretical predictions for how dive duration should vary with foraging success. In particular, in the Atlantic, where foraging success is expected to be higher, dives became much longer than in the Caribbean. The deepest-ever dive profile recorded for a reptile was obtained in the oceanic Atlantic, with a 54-min dive to 626 m on 26 August 2002. However, dives were typically much shallower (generally <200 m) and shorter (<40 min). These results highlight the suitability of this species for testing models of dive performance. [Copyright &y& Elsevier]

Marine turtles in British Columbia have previously been considered off course stragglers. Here we document 20 new reports for Green Turtles, Chelonia mydas, and Leatherback Turtles, Dermochelys coriacea, for the province. Until recently there had been no concerted effort to acquire data on marine turtle abundance or frequency off British Columbia. Observations presented here allow a reassessment of marine turtle status in British Columbia waters. We suggest Green Turtles and Leatherbacks should be considered rare vagrants and uncommon seasonal residents, respectively, off British Columbia and that they are a natural part of the British Columbia marine environment. [ABSTRACT FROM AUTHOR]

Although the general outlines of the development of the skull of turtles are comparatively well known, through the fundamental descriptions by Rathke (1848), and Parker (1880), followed by more recent investigations made by, for instance, Nick (1912) on Dermochelys, and Shaner (1926) on Chrysemys, there are still various problems under discussion, or left unsettled for future research. One reason for the difference of opinion amongst later investigators, is, no doubt, the lack of well-preserved specimens of sufficiently young embryonic stages suitable for examination on complete series of microscopic slides. I have had the opportunity of examining several embryonic stages of the rare Chelonian Dermochelys coriacea, from the collections of the Zootomical Institute of Stockholms Högskola, placed at my disposal by the head of the Institute, professor Nils Holmgren. It is a great pleasure to me to express my gratitude to professor Holmgren for this generous offer. The value of the Dermochelys material is greatly increased by the existence, in the rich collections of embryonic material of the Zootomical Institute, of a fairly complete series of embryonic stages of the Cheloniid Lepidochelys olivacea, as well as various embryonic specimens of other reptiles, including some stages of Chrysemys. As working through the whole material will prove to be a rather comprehensive task, I have preferred to limit the scope of this paper to an attempt at settling two problems which present themselves as comparatively independent of the rest. They are the parashphenoid-problem, and the question of the intertrabecular (taenia intertrabecularis).. [ABSTRACT FROM AUTHOR]