Ecology of Olive Ridley Sea Turtles at Arribadas at Playa La Flor, Nicaragua

Playa La Flor in Nicaragua is one of the few remaining beaches where Olive Ridley Sea Turtles (Lepidochelys olivacea) nest in arribadas. In this study, we present data on the status of the nesting population of L. olivacea on Playa La Flor from 1998 to 2006. Furthermore, in 2004 we established six plots (6 m x 6 m) on a 400-m section of the nesting beach to measure the levels of illegal egg take, clutch hatching success, and hatchling production. The total number of turtles nesting at Playa La Flor increased from 1998 to 2006 where arribadas ranged in size from 167 to 60,816 turtle encounters. In August 2004, 45% of the clutches laid during the arribada were taken illegally from the study plots, whereas these levels were lower during the arribadas occurring from September to November. In 2004, clutch hatching success and hatchling production were higher in plots located high on the beach compared with plots that were closer to or below the high-tide line. Clutch hatching success and hatchling production were higher in the September arribada than during other arribadas within the same year. The lower hatching success and hatchling production of nests laid during later arribadas might be explained by increased nest density, and overlapping clutches in the study plots could lead to an increase in microbial load, O-2 demand, and CO2 production. If manipulating clutches is warranted on Playa La Flor, managers should target clutches that are at the highest risk of drowning, are in areas of high nest density, and are deposited during the larger arribadas that occur later in the nesting season. The location of clutches to be moved/removed might change between years, even on the same beach.