Hierarchical modeling of bycatch rates of sea turtles in the western North Atlantic

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 5:279-289 (2008) - DOI: https://doi.org/10.3354/esr00105 Hierarchical modeling of bycatch rates of sea turtles in the western North Atlantic Beth Gardner1,3,*, Patrick J. Sullivan1, Sheryan Epperly2, Stephen J. Morreale1 1Dept. of Natural Resources, Cornell University, Ithaca, New York 14853, USA 2NOAA, National Marine Fisheries Service, Miami, Florida 33149, USA 3Present address: US Geological Survey, Patuxent Wildlife Research Center, Laurel, Maryland 20708, USA *Email: bgardner@usgs.gov ABSTRACT: Previous studies indicate that the locations of the endangered loggerhead Caretta caretta and critically endangered leatherback Dermochelys coriacea sea turtles are influenced by water temperatures, and that incidental catch rates in the pelagic longline fishery vary by region. We present a Bayesian hierarchical model to examine the effects of environmental variables, including water temperature, on the number of sea turtles captured in the US pelagic longline fishery in the western North Atlantic. The modeling structure is highly flexible, utilizes a Bayesian model selection technique, and is fully implemented in the software program WinBUGS. The number of sea turtles captured is modeled as a zero-inflated Poisson distribution and the model incorporates fixed effects to examine region-specific differences in the parameter estimates. Results indicate that water temperature, region, bottom depth, and target species are all significant predictors of the number of loggerhead sea turtles captured. For leatherback sea turtles, the model with only target species had the most posterior model weight, though a re-parameterization of the model indicates that temperature influences the zero-inflation parameter. The relationship between the number of sea turtles captured and the variables of interest all varied by region. This suggests that management decisions aimed at reducing sea turtle bycatch may be more effective if they are spatially explicit. KEY WORDS: Longline fisheries · Bycatch · Sea turtles · Hierarchical models Full text in pdf format PreviousNextCite this article as: Gardner B, Sullivan PJ, Epperly S, Morreale SJ (2008) Hierarchical modeling of bycatch rates of sea turtles in the western North Atlantic. Endang Species Res 5:279-289. https://doi.org/10.3354/esr00105 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 5, No. 2-3. Online publication date: December 23, 2008 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2008 Inter-Research.