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Project L.1.b - Develop a flexible spatially-explicit ERA approach for quantifying the cumulative impact of tuna fisheries on data-limited bycatch species in the EPO

01 Jan 2018 - 31 Dec 2021

Program(s) in charge: Ecosystem & Bycatch Program
  • To develop a spatially-explicit model for quantifying the cumulative impact of multiple fisheries on data-limited bycatch species in the EPO
  • To use the model to prioritize potentially vulnerable species for further research and/or management
  • To design the model in a user-friendly format to maximize uptake and utilization by IATTC CPCs
  • IATTC is committed, through the Antigua Convention, to ensure the long-term sustainability of all target and associated species impacted by EPO tuna fisheries.
  • Many associated (i.e. bycatch) species lack detailed biological and fisheries data for stock assessment, so data-limited approaches required to identify and assess the most vulnerable species.
  • Productivity-Susceptibility Analysis (PSA) has been widely used, but it cannot provide a quantitative measure of risk, nor can it assess cumulative impacts of multiple fisheries.
Relevance for management
The new model will more reliably identify potentially vulnerable bycatch species and assess their status under current fishing effort regimes to better guide managers
48 months
Workplan and status
  • Jan-Apr 18: complete the development of a preliminary model
  • May 18: present preliminary model and results at SAC-09.
  • Jun-Dec 18: continue model development with feedback from CPCs
  • Jan-Feb 19: Finalize model and user-friendly module
  • Mar-May 19: Finalize assessment of cumulative impacts of EPO tuna fisheries for all bycatch species to identify most vulnerable species.
  • May 19: present final model and assessment results at SAC-10.
External collaborators
  • Presentations at SAC-09 and SAC-10
  • Scientific journal publication
  • Procedure, if successful, to be used annually to assess the vulnerability of bycatch species in the EPO.
Updated date: 01 May 2021
Progress summary for the reporting period
  • An EASI-Fish model was developed for the eastern Pacific stock of the critically endangered leatherback turtle, in collaboration with the Inter-American Convention for the Protection and Conservation of Sea Turtles (IAC) and scientists from the USA and Peru. The stock’s current vulnerability was assessed as well as the potential impacts of implementing a range of conservation and management measures.
  • The 2019 EASI-Fish assessment for Mobula mobular was revised after IATTC internal review and extended to analyze the historic impacts of EPO tuna fisheries on the species’ vulnerability over the past 40 years.
  • The EASI-Fish model itself was further developed and is now a stand-alone Excel package where all uncertainty analyses are undertaken within Excel and no longer relies on the expensive add-in tool “CrystalBall”
Challenges and key lessons learnt
  • In order for EASI-Fish to be widely available and updateable, a web-based version is desirable, although further IATTC resources are needed.
  • More sophisticated habitat models (e.g. MaxEnt, INLA) may provide more reliable base maps for habitat and will be considered in future analyses.
  • Griffiths, S.P., Wallace, B., Swimmer, Y., Alfaro-Shigueto, J., Mangel, J.C., Oliveros-Ramos, R., 2020. Vulnerability status and efficacy of potential conservation measures for the east Pacific leatherback turtle (Dermochelys coriacea) stock using the EASI-Fish approach. 10th Meeting of the IATTC Working Group on Bycatch, 7 May 2020, La Jolla, California, USA. Document BYC-10 INF-B, 41.
  • Griffiths, S.P., Kesner-Reyes, K., Garilao, C., Duffy, L.M., Rom├ín, M.H., 2019. Ecological Assessment of the Sustainable Impacts of Fisheries (EASI-Fish): a flexible vulnerability assessment approach to quantify the cumulative impacts of fishing in data-limited settings. Marine Ecology Progress Series 625, 89-113.
  • Griffiths, S.P., Lezama-Ochoa, N., 2021. A 40-year chronology of spinetail devil ray (Mobula mobular) vulnerability to eastern Pacific tuna fisheries and options for future conservation and management. Aquatic Conservation: Marine and Freshwater Ecosystems 31, 2910–2925.
  • An invited keynote presentation entitled “EASI-Fish: a flexible vulnerability assessment tool for quantifying the cumulative impacts of tuna fisheries on data-poor bycatch species” was given at the Joint tRFMO Bycatch Working Group Meeting in Porto, Portugal, 16-18 December, 2019.
  • A presentation was given at the 70th Tuna Conference “Assessing potential conservation measures for data-poor mobulid bycatch in the eastern Pacific Ocean tuna fishery using the “EASI-Fish” ecological risk assessment tool” in May 2019.
EASI-Fish was developed in Microsoft Excel to maximize its acceptance and utilization by IATTC CPCs and more broadly.