Science Serving Maryland's Coasts
Dong Liang, Ph.D.
Chesapeake Biological Laboratory
Using Fisheries Data to Predict the Occurrence of Bycatch for Leatherback Sea Turtles (Dermochelys coriacea) in the Southeast Pacific
The leatherback sea turtle population (Dermochelys coriacea) has suffered a major decline in recent years. This drop has many causes, including coastal egg poaching and pelagic fisheries bycatch; the latter is believed to be the leading cause of pelagic adult leatherback mortality. Then, in order for the population to recover, fisheries bycatch must be reduced. In this study, we created a spatiotemporal Species Distribution Model (SDM) that incorporates remote sensing data of the seascape into the dynamic management of the Eastern Pacific (EP) leatherback population in the Southeast Pacific. We obtained leatherback observation data from multiple fisheries that have operated in the southeastern Pacific over the past several decades. We applied a dynamic Poisson Process Model to generate pseudo-absence data and predictions of leatherback intensity as a function of dynamic environmental covariates. Model comparisons were performed based on likelihood ratio tests and prior expectations for leatherback intensity. The chosen model revealed a somewhat circular movement pattern in the southeast pacific, as well as greater leatherback presence in the southern reaches of the study range in December, as opposed to June. It is our hope that this model can be used to reduce future leatherback bycatch.
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