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ESR prepress abstract   -  DOI: https://doi.org/10.3354/esr01305

Vulnerability status and efficacy of potential conservation measures to reduce tuna fishery bycatch of the Critically Endangered East Pacific leatherback turtle Dermochelys coriacea

Shane P. Griffiths*, Bryan Wallace, Verónica Cáceres, Luz Helena Rodríguez, Jon Lopez, Marino Abrego, Joanna Alfaro-Shigueto, Sandra Andraka, María José Brito, Leslie Camila Bustos, Ilia Cari, José Miguel Carvajal, Ljubitza Clavijo, Luis Cocas, Nelly de Paz, Marco Herrera, Ann Marie Lauritsen, Jeffrey C. Mangel, Miguel Pérez-Huaripata, Rotney Piedra, Javier Antonio Quiñones Dávila, Liliana Rendón, Juan M. Rguez-Baron, Heriberto Santana, Brian Stacy, Jenifer Suárez, Yonat Swimmer, Callie Veelenturf, Rodrigo Vega, Patricia Zárate

*Corresponding author:

ABSTRACT: Industrial tuna and artisanal fisheries targeting multiple species in the eastern Pacific Ocean (EPO) interact with the Critically Endangered East Pacific (EP) leatherback turtle Dermochelys coriacea. In 2021, a revised Inter-American Tropical Tuna Commission (IATTC) resolution on sea turtles aimed to reduce sea turtle bycatch in EPO industrial tuna fisheries and ensure their safe handling and release. A new ecological risk assessment approach—Ecological Assessment for the Sustainable Impacts of Fisheries (EASI-Fish)—was used to assess vulnerability status and to better understand the potential efficacy of 70 scenarios that compared simulated conservation and management measures (CMMs) for EPO industrial (purse-seine and longline) and artisanal (longline and gillnet) fisheries to the status quo in 2019. In 2019, fishing mortality (2019) and the breeding stock biomass per recruit (BSR2019) exceeded precautionary biological reference points (F80% and BSR80%), classifying the stock as “most vulnerable”. Industrial and artisanal longline fisheries had the highest impacts because they had the highest areal overlap with the modelled EP leatherback species distribution. Of the 70 CMM scenarios, 42 resulted in significant improvements in vulnerability status (i.e. to “least vulnerable”). Although use of large circle hooks, finfish bait, and best handling and release practices each decreased vulnerability, the most effective scenarios involved using these 3 measures in concert. Although benefits predicted from EASI-Fish for CMM scenarios assume full compliance and attaining the modelled levels of efficacy, our modelling provides stakeholders with evidence-based recommendations to address key threats to EP leatherback turtles to improve their conservation status by reducing fishing impacts.