Withdrawn post-notification Oral Australian Society for Fish Biology Conference 2022

EASI-Fish – A Flexible Catch-Independent Approach for the Quantitative Assessment of the Cumulative Impacts of Fisheries on Bycatch in Data-Limited Settings (#137)

Shane Griffiths 1 , Leanne Fuller 1 , Kathleen Kesner-Reyes 2 , Cristina Garilao 3
  1. Inter-American Tropical Tuna Commission, La Jolla, CALIFORNIA, United States
  2. The WorldFish Center, Los Baños, Philippines
  3. GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany

Ecosystem approaches to fisheries are being increasingly adopted by fisheries to demonstrate ecologically sustainability. However, for fisheries that interact with many data-poor species, demonstrating sustainability of each species is often not feasible using conventional stock assessment methods. Ecological Risk Assessment (ERA) approaches, such as Productivity-Susceptibility Analysis, have been a popular alternative in data-limited fisheries to identify potentially vulnerable species. Unfortunately, most existing ERA methods produce only a relative measure of vulnerability, lack biologically meaningful reference points, cannot assess the cumulative impact of co-occurring fisheries, or lack the capability to characterise existing spatio-temporal and input control management measures. This paper introduces a spatially-explicit ERA approach designed to assess the cumulative impact of multiple fisheries on bycatch species in data-limited settings by producing a quantitative estimate of fishing mortality using a flexible susceptibility analysis independent of catch data. Fishing mortality is compared to conventional biological reference points derived from length-based per-recruit models to determine a species’ vulnerability status. EASI-Fish allows fisheries managers to more confidently identify vulnerable species in which to direct resources to either implement mitigation measures, or collect further data for further assessment. Furthermore, EASI-Fish can be used to explore ‘what if’ scenarios in the development of conservation and management measures aimed to reduce bycatch vulnerability, such as spatial closures or changes to gear configurations. The development of EASI-Fish is described in the context of its application to a subset of teleost, elasmobranch, sea turtle and cetacean bycatch species caught by industrial and artisanal tuna fisheries in the eastern Pacific Ocean where many developing coastal states lack fishery data collection programs. Examples are provided of applications of EASI-Fish to assess the vulnerability of shark bycatch species and assessing the efficacy of proposed conservation measures for the spinetail devil ray (Mobula mobular) and the critically endangered leatherback sea turtle (Dermochelys coriacea).