A review of methods for assessing the impact of fisheries on sea turtles

There are growing concerns on the impacts of marine fisheries in vulnerable bycatch species, such as sea turtles. The International Commission for the Conservation of Atlantic Tunas (ICCAT) is preparing an assessment on the impacts of ICCAT fisheries on sea turtle populations, with the assessments scheduled to start in 2013, and the data preparation starting in 2012. Integrated in this process, this document was prepared to compile, describe and revise some currently available methodological approaches to analyse the interactions and impacts of fisheries on sea turtle populations. The following analysis are addressed: modelling (standardizing) bycatch rates, analysing and modelling mortality rates, studies on the effects of hook styles and bait types, and methods for conducting Ecological Risk Assessment (ERA). The issue of data overdispersion and zero-inflation, common on bycatch of pelagic longline fisheries is addressed, and some possible modelling alternatives are presented. Summary tables with a compilation of data useful for conducting an ERA on sea turtles impacted by ICCAT fisheries are provided.