Biology and Management of Olive Ridley Turtles (Lepidochelys olivacea) in Central America

The purpose of this dissertation was to understand the applied biology of the olive ridley turtle nesting arribada at Playa Ostional, Costa Rica, and Playa La Flor and Playa Chacocente in Nicaragua. Harvest of eggs fromthese beaches was not sustainable. Hatchling production at Ostional and La Flor was insufficient to maintain the current populations of adults and production of hatchlings at Chacocente was marginal. To help ensure the stability of the regional olive ridley population it will be necessary to produce as many hatchlings as possible from the beaches and to reduce at sea mortality of the turtles for the foreseeable future. Hatching success and the production of hatchlings were controlled by the same spatial, temporal, human and environmental factors on all three beaches so those controls appear to be general in nature, at least in the Central American Pacific coast. Density of eggs did not have a significant effect on hatching success or hatchling production. Plots open to harvest, dogs and poaching did not have higher hatching success or higher hatchling production. Thus, removal of eggs by humans and their animals is not an effective means to increase the number of hatchlings produced from these beaches. The best way to increase hatchling production is stop poaching, reduce dog predation, and find ways to increase hatching success. It is not practical to eliminate the harvest at Ostional because the harvest provides important income for the members of ADIO. However, the legal harvest can be restricted to the dry season when eggs typically die from heat and lack of water. In the wet season harvest can be restricted to eggs that are on the surface of the sand due to digging by turtles and eggs that are in danger of being washed away by the estuaries and tides. Ecotourism now produces more income at Ostional than the legal egg harvest. A combination of a well-managed harvest of doomed eggs and ecotourism would provide a conservation plan that would eventually provide new income for local residents and increase hatchling production. A participatory management program is needed on the other beaches as well.Ph.D., Environmental Science -- Drexel University, 201