Monitoring of Olive Ridley Sea Turtle Populations at Nancite Beach, Santa Rosa National Park, Costa Rica

Abstract

Nancite beach in the Guanacaste Conservation Area is of worldwide importance for the Olive Ridley sea turtle (Lepidochelys olivacea). Nesting at Nancite occurs not only individually, but also synchronously. Turtles emerge in groups of up to 100,000, over the course of 6-7 nights and days, in a phenomenon unique to the genus Lepidochelys, known as an arribada. Few beaches are known where arribadas for this species occur. These include Gahirmatha and Nadiakhia Muhana on the Pacific coast of India (Karr 1982); Escobilla on the Atlantic coast of Mexico (Cliffion et al 1982); and Nancite and Ostional on the Pacific coast of Costa Rica (Richard and Hughes 1972). Nancite is unique because it is a fully protected area where no harvesting of eggs is allowed. Arribadas at Nancite were first discovered by Richard and Hughes in 1970 (Richard and Hughes 1972) and marking of Olive Ridleys was started by Hughes in 1971. In 1980 a systematic study monitoring abundance, distribution and migration of Olive Ridleys was undertaken by Cornelius and has been continued by Dr. Mo and the National University of Costa Rica.