Assessing Pinniped Bycatch Mortality with Uncertainty in Abundance and Post-Release Mortality

In a new case study from Chile, researchers from the Ocean Modeling Forum’s Marine Mammal Bycatch Working Group adapted a marine mammal stock assessment method to use sporadic data on bycatch mortality for species impacted by multiple fisheries. The team applied their adapted method using observer data from industrial and artisanal purse seine and trawl fisheries as well as surveys for South American sea lions (Otaria byronia) and South American fur seals (Arctocephalus austrailis) off Chile. Results show that this method can account for uncertainty associated with monitoring operations and the impact of post-release mortality, which is particularly useful for fisheries that have some bycatch data, including on post-release mortality, and could assist countries that need to evaluate whether bycatch mortality is comparable with conservation policy goals.

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Punt, A.E., Sepúlveda, M., Siple, M.C., Moore, J., Francis, T.B., Hammond, P.S., Heinemann, D., Long, K.J., Oliva, D., Reeves, R.R., Sigurðsson, G., Víkingsson, G., Wade, P.R., Williams, R., Zerbini, A.N. (2020). Assessing pinniped bycatch mortality with uncertainty in abundance and post-release mortality: A case study from Chile. Fisheries Research. https://doi.org/10.1016/j.fishres.2020.105816