Catch per unit effort and population structure of the Pacific green turtle (Chelonia mydas) in the Golfo Dulce, Costa Rica.
The Golfo Dulce is one of the few tropical fjords in the world, and has recently been declared a Marine Area for Responsible Fisheries (AMPR), harboring mangrove ecosystems, coral reefs and seagrass beds, which are important feeding areas for green turtles (Chelonia mydas). In this study we estimate the catch per unit effort (CPUE) and population structure in a site in the western sector of the Golfo Dulce. Between August 2010 and March 2013, were captured a total of 253 green turtles (including 20 recaptures) using entanglement nets. The annual CPUE (CPUE, 1 unit: 100m of net for 7h) during the study ranged between 0.19 and 0.45, decreasing gradually over the years, possibly prompted by mass mortality occurred in January 2013. We found that seasonality and temporality influence the CPUE according to the best-fit model. About 78.17% were considered adult females, with an average length of curved carapace (LCC) of 79.6±0.9cm. The female recaptured has been tagged previously in the Galapagos Archipelago. While none of the turtles tagged in the Golfo Dulce was reported nesting on any other beach. Our results suggest that the Golfo Dulce is an important area for green turtles, where individuals congregate for adults and subadults would feed on seagrasses and the fleshy parts of the mangroves. The area also represents a major challenge for international conservation, possibly because we captured adult females from nesting beaches of Panama and Colombia, which requires multilateral agreements that promote the recovery of the East Pacific green turtle. We suggest the continuation of this conservation project to use sea turtles as umbrella species to protect ecosystems in the Golfo Dulce.