Various policies and programs aim to generate benefits to local people while conserving biodiversity or a particular species. In Central America, policies to promote sea turtle conservation in the face of egg and turtle harvests include pure enforcement of regulations, performance-based payments for conservation, ecotourism paired with enforcement, alternative livelihood projects, community-based resource management, and de facto open access. This project develops a bio-economic model of sea turtle populations and egg/turtle harvest decisions as a basis for comparing across these various settings and approaches to sea turtle conservation and their impact on rural livelihoods. The biological side of the model focuses on the level of surviving hatchlings that enter the sea. The economic side of the model focuses on individual conservation or egg harvest behavior using a labor allocation model within an institutional setting. The model characterizes the range of sea turtle conservation policies, village institutions, and market settings seen worldwide, and particularly in Central America. Analysis of the bio-economic model identifies characteristics of the biological, social, and economic systems that generate strong conservation and/or livelihood impacts. The output shows trade-offs between livelihoods and conservation in different bio-economic settings. We then use the model as a lens to examine the sea turtle conservation programs in Nicaragua and Costa Rica, which will identify likely reasons for success and failure of those programs and approaches that could improve conservation and livelihood outcomes.