A Stage-Based Population Model for Loggerhead Sea Turtles and Implications for Conservation

Management of many species is currently based on an inadequate under- standing of their population dynamics. Lack of age-specific demographic information. particularly for long-lived iteroparous species. has impeded development of useful models. We use a Lefkovitch stage class matrix model. based on a preliminary life table developed by Frazer (1983a), to point to interim management measures and to identify those data most critical to refining our knowledge about the population dynamics of threatened log- gerhead sea turtles (Caretta caretta). Population projections are used to examine the sen- sitivity of Frazer's life table to variations in parameter estimates as well as the likely response of the population to various management alternatives. Current management practices appear to be focused on the least responsive life stage. eggs on nesting-beaches. Alternative protection efforts for juvenile loggerheads. such as using turtle excluder devices (TEDs). may be far more effective.