Internesting and migratory movements of female leatherback turtles (Dermochelys coriacea) from Kamiali Wildlife Management Area were tracked by satellite telemetry during the 2001–2002 and 2002–2003 nesting seasons, and an aerial survey of nearly 2800 km of the north Papua New Guinea coastline and New Britain Island was conducted during January 2004. Nesting occurred during November–March at the Kamiali Wildlife Management Area monitoring beach with peak activity during December–January. Telemetry results indicated that nesting females used Huon Gulf waters adjacent to the nesting beach and renested inside and outside the protected area within the Kamiali Wildlife Management Area. After nesting, the turtles migrated over deep waters in a southeastern direction to high latitude waters of the South Pacific Ocean.

In Brazil, the only area where regular leatherback sea turtle (Dermochelys coriacea) nesting is known to occur is located on the northern coast of the state of Espírito Santo, around latitude 19°S. In this study, we present the field methods used by Projeto TAMAR-IBAMA (the Brazilian Sea Turtle Conservation Program) in the state of Espírito Santo and analyze data on leatherback nesting from 1988–1989 to 2003–2004. In that period, 527 nests were observed in the study area. The annual number of nests varied between 6 (in 1993–1994) and 92 (in 2002–2003). Between 1995–1996 and 2003–2004, the annual number of nests increased at about 20.4% per year on average. Among the 527 clutches observed, 358 (67.9%) were left in situ, 50 (9.5%) were relocated to another spot on the beach, 88 (16.7%) were relocated to open-air beach hatcheries, and 31 clutches (5.9%) did not have their management decision recorded. Curved carapace length of nesting females was in the range of 139–182 cm (mean = 159.8 cm). At present, there is no significant alteration of the nesting habitat in Espírito Santo, egg poaching has been reduced to very low levels, and there is no subsistence hunting for sea turtles of any species. The main challenges to leatherback conservation currently are the incidental capture in artisanal fisheries operating close to nesting beaches and in high seas fisheries operating in the South Atlantic, as well as activities related to the oil industry. An overview of Projeto TAMAR's actions addressing current sea turtle conservation issues in the State of Espírito Santo is presented.

The northwest coast of the province of Papua in Indonesia is thought to host the largest remaining leatherback nesting population in the Pacific Ocean. We conducted a census of nesting activity at Jamursba-Medi from 2001 through 2004 and of Wermon from 2002 to 2004, and tracked internesting movements of female leatherbacks by using satellite telemetry during the nesting season in 2003. We recorded 1865–3601 nests each season at Jamursba-Medi and 1788–2881 nests at Wermon. Nesting occurred year-round, with a peak in activity between May and September at Jamursba-Medi, and between October and March at Wermon. Comparing these data with previous records of nesting activity from 1981 to 2001 indicates that, although there are indications of a long-term decline, this population has not been depleted to the extent found at other major rookeries in the Pacific. Satellite telemetry indicates that nesters frequent waters around the Raja Ampat Islands and coastal waters to the west of Jamursba-Medi, and may also nest outside the monitored area. We recommend establishing a marine protected area to ensure protection of this population in these critical nearshore marine habitats and implementation of conservation measures in partnership with local communities at these nesting beaches before this population becomes depleted.

Nesting of leatherbacks in French Guiana and Suriname has been monitored for more than 30 years. Given the documented exchange of tagged females across the nesting beaches, leatherbacks found on the 6 principal nesting areas in French Guiana and Suriname are considered to be a single large nesting population. Despite more than 3 decades of work on this population, this population's status remains unclear. Here we describe the most recently available estimates of various life history parameters and describe the trend of the number of nests laid in the region over the past 36 years. Our analyses suggest that the trend of the whole population in French Guiana and Suriname is stable or slightly increasing over this time period. We strongly urge the continued monitoring of the population by the different research groups in the region so that future data sets will enable an accurate description of the status of this leatherback population.

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 haplotypes 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.

The number of leatherback turtles (Dermochelys coriacea) nesting at Parque Marino Las Baulas declined precipitously in the 15 years that we monitored the population (1988–1989 to 2003–2004). We estimate that the annual survival rate of adults was 0.78 (95% CI: 0.75–0.80) and that mortality rates for juveniles and subadults in the ocean appear to be double those of a stable population. The proportion of hatchlings produced from deposited eggs increased since the park was established as a result of conservation practices. Because the number of nesting females decreased, the overall production of hatchlings per season declined but was much greater than would be expected without protection efforts. There were similar numbers of hatchlings leaving the beaches of Las Baulas in 1998–2003, with 68 to 188 nesting females under the current conservation regime as there were in 1988–1989 with ca. 1500 nesting females and no park. Female leatherback turtles that nest at Las Baulas have a high level of exchange between nesting beaches; thus, protection of both Playa Grande and Playa Langosta is critical for the survival of the population. Despite current protection efforts, the population at Las Baulas is still threatened by mortality at sea and development on and behind the nesting beaches.

Observed clutch frequency is the observed number of clutches deposited by a female turtle in a single nesting season. This value is generally biased compared to the true nest number because some clutches could have been missed by beach patrols. We constructed an analytical model to search for the distribution of observed clutch frequency according to 1) the distribution of the clutch number per female, 2) the probability of female capture on the beach, and 3) the probability that a female was an intraseasonal one-time nester. We used data from 1987 to 2003 collected on leatherbacks nesting on Yalimapo beach in French Guiana to test the power of the model. Whereas for 13 of the 16 years, the model produced estimates concurrent with the field data; for the other 3 years, there was no concordance, indicating a lack of power of the model. We describe a required level of capture effort on the beach that will be sufficient for the model to adequately describe clutch frequency across the nesting season. This level is the product of the proportion of the season monitored times the instantaneous probability of the presence and the detection for a particular female during 1 nesting event.

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 juveniles 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.

Spatial use of nesting habitat by Dermochelys coriacea is analyzed on a beach with intense tourism use on Margarita Island. There are no previously published data in Venezuela about the use of nesting habitat by leatherback sea turtles and the effects of human activities on nest location and hatching success. Data were collected during nightly intensive beach patrols on Playa Parguito beach (1.6-km long) from March through August 2001. Thirty-one females nested on the beach, and we found 74 nests. The average distance between pairs of nests from the same female was 498 m, although modal distance was between 200 and 300 m. The average distance between randomly selected pairs of nests from any female was 451 m. No special preference for a certain part of the beach for each female was found. Spatial analysis indicated nesting aggregates toward the most suitable portions of the beach: those with fewer risk factors (light pollution, concentration of beach furniture and umbrellas). Our results show nesting behavior change, causing decreased nesting in areas where the best hatching rates occurs. Hatching success was significantly higher in the southern part of the beach, but the larger number of clutches were laid in the northern area, where hatching success was the lowest. Hatching rate for in situ clutches was 47.18%, which was significantly higher than that obtained for nests moved into a hatchery (33.1%) or for nests relocated to a safer part of the beach (27.8%).

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 PIT-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 hatching) 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-Surinamese 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 non-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.

Field research was conducted, from 1990 to 2004, at Gandoca 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 be 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 in the number of nests laid since 2000.

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 in 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%.

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 Tortuguero, 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 1 moved into the northwest Atlantic Ocean. Minimum rates for illegal egg collection from 2000 to 2005 were estimated at 13.0%–21.5%.

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.

Leatherback nesting 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 be among the largest in the world.

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 gillnet 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.

Leatherback turtles, Dermochelys coriacea, have not previously been reported nesting in Vanuatu. A review of archival data, unpublished reports, interviews with key informants from coastal communities, and a nesting beach survey indicates that leatherback nesting occurs on a number of islands, including Pentecost, Ambrym, Malakula, Epi, and Efate. Leatherbacks are opportunistically consumed in some areas, particularly Malakula, where 5 have been reported killed in the past 7 years.

Since 1943, a total of 40 leatherbacks have been documented in neritic and offshore waters of the Gulf of California, Mexico: 13 as fisheries by-catch, 11 in indigenous ceremonies, 8 coastal strandings, 4 at-sea sightings, 3 observed by fishing fleets, and 1 via satellite telemetry. Leatherback hatchlings were observed on 3 occasions in the northern Gulf of California. The range of curved carapace lengths for nonhatchling leatherbacks was 113 to 160 cm curved carapace length (mean = 139 ± 12 cm). All but 1 leatherback were reported between November and May, a period of cooler water temperatures for the region.

Over 4 years, 2001–2004, leatherback-turtle monitoring was conducted on all the potential nesting sites in French Guiana. We estimated minimal leatherback turtle nest numbers of 23,107, 12,229, 13,480, 11,012, respectively. The Awala-Yalimapo Beach, sometimes considered a good estimator of the overall nesting activity for the country, has hosted a significant proportion of the leatherback turtle nests (42% ± 2%), but this percentage is much lower than formerly described. The relative importance of this nesting site is discussed in light of remote sensing data, suggesting that nest numbers recorded in Awala-Yalimapo may have misrepresented leatherback turtle population trends. Indeed, remote sensing data indicate that the total sandy shoreline available in French Guiana has regularly evolved over the last decades, allowing leatherback turtle nesting attempts out of the scope of monitoring. The importance of a monitoring effort integrating the specific coastal dynamic of the Guianas region is highlighted.

We describe a low-risk, alternative technique for sampling blood from leatherback turtles (Dermochelys coriacea) using interdigitary vessels in their flippers. Because this technique allows for repeated, large-volume blood samples without requiring restraint of turtles, the technique is preferred over using the dorsal cervical sinus in almost all cases of blood sampling from leatherbacks, and also applies to other sea turtle species.

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 trans-Pacific migration by a leatherback turtle.

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 leatherbacks.