. Marine turtles often conduct extensive migrations from foraging to breeding habitats. Turtles may spend several months in these breeding habitats, while periodically taking brief excursions onto terrestrial environments to nest. Identification and protection of these breeding habitats over the duration of the reproductive season is therefore vital for the conservation of sea turtles. Here, we used satellite telemetry to investigate the internesting behavior of East Pacific green turtles from 2 nesting beaches: Nombre de Jesús and Playa Cabuyal, located 50 km apart on the Pacific coast of Costa Rica. A total of 21 satellite transmitters were deployed at Nombre de Jesús ( n = 8) between 2007 and 2009 and at Cabuyal ( n = 13) between 2012 and 2015. We found that turtle movements and dive behaviors were notably different between the 2 beaches. Specifically, the turtles from Cabuyal engaged in deeper dives (10 ±3 m vs. 6.5 ±2 m [mean ±SD]), presumably because they had access to deeper waters, and had larger minimum convex polygon area (606.5 ± 1150.5 km 2 vs. 16 ± 11 km 2 ) than turtles from Nombre De Jesús. Turtles from Nombre de Jesús also engaged in shorter dives (6.68 ± 4.5 min), compared with Cabuyal, where a majority of dives lasted between 10 and 30 min (18.75 ± 5.6 min). Finally, turtles at Nombre de Jesús dove significantly deeper during the day compared with the night, a pattern that was not present at Cabuyal. We conclude that internesting behaviors can be different even between beaches within the same geographical area. As such, internesting habitat management plans should pay specific attention to potential site-specific variation in internesting behaviors.

We collected tissue samples from 41 nesting hawksbill turtles ( Eretmochelys imbricata ) at Sandy Point National Wildlife Refuge, St. Croix, US Virgin Islands, to characterize the genetic structure of this rookery in terms of mitochondrial DNA; we compared haplotype frequencies from this rookery to those from Buck Island, another hawksbill nesting beach on St. Croix. Pairwise F ST comparisons showed that Sandy Point was demographically distinct from Buck Island ( F ST = 0.501, p < 0.001), a finding reinforced by significantly different haplotype frequencies (χ 2 = 51.76, p < 0.001) and a lack of interchange of nesting females between both sites based on mark–recapture data. Our results support the delineation of the nesting populations at Sandy Point and Buck Island into separate units for the purposes of management.

Coastal development can alter the natural dynamics of beach environments, with strong implications for associated biota. Sea turtles nest on oceanic beaches and often depend upon a specific range of conditions for successful nesting. In the case of the critically endangered leatherback turtle ( Dermochelys coriacea ), we know little regarding what features they select for nest sites, including how they respond to anthropogenic development. We examined relationships between leatherback nest frequency, beach environments, and tourism development at Playa Grande, Costa Rica, the location of the largest current nesting population in the eastern Pacific Ocean. Developed beach sections had shallower slopes, lower pH, and less air-filled pore space, but higher water content and salinity than undeveloped areas. Developed areas were also comprised of more sand in the smaller grain size classes relative to undeveloped sections. Leatherback nesting was positively correlated with deepness of the offshore approach, beach slope and elevation, pH, and sand in intermediate size classes (0.025-mm diameter), but negatively correlated with sand in the smallest silt size class (< 0.0625-mm diameter). Leatherback nesting frequency was 3.4 times higher in undeveloped sections of the beach relative to developed areas, while nonnesting emergences were 2.6 times more likely in developed relative to undeveloped areas. It is apparent that coastal development has impacted beach environments with consequences for leatherback nest site distribution. It is likely that additional development of the beach under mixed-management plans to support a growing tourist industry will further degrade the attractiveness and quality of the beach for leatherback nesting.

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.

The high probability of being depredated on the crawl to the water may have influenced the evolutionary processes of hatchling sea turtles on the beach. During this time hatchlings must locate water and move as quickly as possible in order to reduce the time spent on the beach. Hatchling leatherback turtles ( Dermochelys coriacea ) at Playa Grande, Parque Nacional Marino Las Baulas, Costa Rica, spent on average 34 minutes visible on the beach, covered a distance of 46.8 m, and moved at a rate of 3.11 m/min. During the time on the beach, 12% of hatchlings were eaten by predators, 83% reached the water, and 5% were determined as potential mortalities (hatchlings were stuck on debris, vegetation, or upside down). The main predators of hatchling leatherbacks at Playa Grande were ghost crabs ( Ocypode occidentalis ), great blue herons ( Ardea herodias ), and yellow-crowned night herons ( Nycticorax violaceus ) during the night, and crested caracaras ( Caracara plancus ) during the day. Tracks left by the hatchlings on the sand were straighter as they approached the water. Dispersion (distance between the 2 outermost tracks coming from a nest) was correlated with number of hatchlings crawling. Hatchling leatherback turtles at Playa Grande are threatened by predation by domestic animals. Hatchling mortality due to human-related activities is likely to increase in the future due to increasing pressure from tourism at Parque Nacional Marino Las Baulas.

ABSTRACT 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.