. 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.

Here we report on a newly discovered nesting population of east Pacific green turtles ( Chelonia mydas ) in northwest Costa Rica at San José Island, Murciélago Archipelago, that rivals those of Mexico and the Galápagos Islands, Ecuador. A total of 1232 individual green turtles were tagged over 4 nesting seasons (2012–2013 to 2015–2016). Mean (± SD) annual number of nests (1077 ± 414; range, 490–1698 nests) and females (306 ± 133; range, 164–466 females) was higher than those previously reported for Pacific Costa Rica. The number of deposited nests was similar to that registered on the Galápagos main beaches, but density of nests (number of nests/km) was the second highest for any green turtle beach in the eastern Pacific. Reproductive output was similar (mean clutch frequency: 4.4 ± 2.2 clutches and mean clutch size: 75.8 ± 14.6 eggs/clutch), and mean hatching success was higher (0.89 ± 0.14) than those reported at other sites in the eastern Pacific. Because the study site was located on an island within a protected area, several of the common threats that sea turtles face at more accessible mainland sites (i.e., egg poaching, tourist development, and predation by large mammals) were absent. Our data indicate that San José Island is the most important nesting site for east Pacific green turtles in Central America. The large size of this population, along with its isolated and protected status, suggest that this rookery is making a significant contribution to the conservation of east Pacific green turtles. Additional information at the country level will help determine the relative importance of Costa Rica for green turtle nesting in the broad eastern Pacific region.

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.