Hawksbill turtles Eretmochelys imbricata in El Salvador: nesting distribution and mortality at the largest remaining nesting aggregation in the eastern Pacific Ocean

摘要

El Salvador has a series of nesting beaches that together host the highest remaining nesting abundance of hawksbill turtles Eretmochelys imbricata in the eastern Pacific Ocean. However, the distribution of hawksbill turtle nesting and causes of hawksbill mortality along the Salvadoran coast are yet to be described. Here, we report on life history information of this population, including body size of nesting hawksbill turtles and clutch size, and mortality along nesting habitat at the following 3 areas in El Salvador: Los Cóbanos Reef Marine Protected Area (Los Cobanos), Bahia de Jiquilisco-Xirivaltique Biosphere Reserve (Bahia), and Punta Amapala. In 2008, we recorded 310 nesting events by hawksbill turtles over 51.6 km of nesting habitat, giving an overall nesting density of 6.0 nests km~(-1); nearly 62 % of total nesting activity and the highest reproductive output occurred in the Bahia. Morphometric data were collected from 26 nesting turtles that ranged from 74 to 88 cm curved carapace length (mean ± SD; 81.6 ± 3.6 cm) and 63 to 76 cm curved carapace width (70.1 ± 3.4 cm). Between 2004 and 2008, a total of 24 hawksbill turtles died in the mangrove and estuarine habitats of the Bahia (18 attributed to blast fishing) and in 2008, 8 hawksbill turtles died due to bycatch in bottom-set gillnets in Los Cobanos. Given the severely depleted status of hawksbill turtles in the eastern Pacific, conservation action is urgently needed to mitigate their incidental capture in artisanal fisheries gear at primary nesting and foraging areas in El Salvador.