Funded
Click to see projects by theme, goal or target:
- Objectives
- Update the Ecopath ecosystem model developed for the eastern tropical Pacific Ocean (ETP) by Olson and Watters (2003).
- Convert the model to Ecopath with Ecosim (EwE) software version 6.5.
- Update the model with annual catch, discards, fishing mortality and fishing effort data for each functional group from 1993 to present.
- Calibrate the model with new catch and effort time series to improve the reliability of model forecast outputs.
- Produce annual ecological indicators for inclusion in the Ecosystems Considerations report as standardized measures of ecosystem integrity.
- Background
- IATTC is committed, through the Antigua Convention, to ensuring the longterm sustainability of all target, associated and dependent species impacted by EPO tuna fisheries.
- Although the IATTC undertakes stock assessments for economically important species and ecological risk assessments (e.g. PSA, EASI-Fish) to prioritize research and management of non-target species, these single-species assessments do not take into account possible impacts on ecosystem dynamics through changes in the strength of trophic linkages due to anthropogenic and/or climate impacts.
- Olson and Watters (2003) developed an Ecopath ecosystem model of the ETP for 1993, with dynamic simulations extended to 1999.
- No further updates or development of ecosystem models for the EPO have been undertaken by the IATTC staff, due to the departure of key members with ecological modelling expertise.
- Relevance for management
- The ETP model will be available in EwE 6.6, which can more rapidly provide annual updates of a range of ecological indicators to provide standardized measures of the integrity of the ETP ecosystem.
- The ETP model can be used to simulate ‘what if’ hypotheses relating to changes in fishing activities (e.g. use of FADs) and/or climate drivers on the ETP ecosystem structure, and individual functional groups and key species.
- Conservation and management recommendations for vulnerable species may be developed, based on model outputs.
- Duration
- 36 months
- Workplan and status
- Jun–July 2018: Convert model to EwE version 6.5.
- Mar 2019: Update model with new catch data for 1993-2017.
- Apr–May 2019: Produce ecological indicator values for 1993-2017 and run hypothetical fishery scenarios and present findings at SAC-10.
- Jun–Dec 2019: Collaborate with the Stock Assessment Group to update time series of biomass, fishing mortality and catch data for the ETP.
- Jan–Mar 2020: Calibration of model to new data time series.
- Apr–May 2020: Produce ecological indicator values for 1993-2018 and run hypothetical fishery scenarios and present findings at SAC-11.
- Jun–Dec 2020: Explore expansion of ETP model to be spatially explicit using Ecospace.
- Jan–Mar 2021: Update model with new data for 1993-2019 and calibrate model to new data time series.
- Apr–May 2021: Produce ecological indicator values for 1993-2019 and run spatially-explicit hypothetical fishery scenarios and present findings at SAC-12.
- Deliverables
- A new version of the ETP model Olson and Watters (2003) that will exist in the latest version of EwE software with updated data time series of catch, effort, and also biomass and fishing mortality where available.
- Annual updates of ecological indicators to provide standardized measures of the integrity of the ETP ecosystem.
- Updated date: 01 May 2023
- Progress summary for the reporting period
- Model updated with new catch data time series for 1993–2018.
- Ecological indicator values for 1993–2018 produced from new model and included in the Ecosystem Considerations report.
- Staff successfully completed a 1-week Ecopath training course in Florida in December 2019 to develop skills that will be necessary to construct a spatially-explicit ecosystem model of the EPO.
- Challenges and key lessons learnt
- The predator-prey matrix underlying the ecosystem model is based on stomach contents data from the early 1990s. The staff recommends, that Proposal F.3.a be funded, to obtain updated morphometric measurements and biological samples to best represent the current dynamics of the EPO ecosystem
- SAC-12-13 Ecosystem model of the EPO: progress report
- Presentation at SAC-10
- SAC-10-14 Ecosystem considerations
- SAC-10-15 Towards standardized ecological indicators for monitoring ecosystem health: an updated ecosystem model of the tropical EPO
- SAC-12-13 Ecosystem model of the EPO: progress report
- SAC-14-14 Ecosystem Considerations