Update the stock assessment of Alfonsino stocks in the SIOFA area. This should build on and improve the work of the previous assessment (Brandão et al. 2020). The outcomes of this assessment should be collated in a report and presented to SC11 in 2026.
In order to evaluate recent trends in the population of alfonsino and in the absence of a stock assessment a CPUE analysis will provide information on the recent population trends of alfonsino in the SIOFA area. In addition, length frequency trends can provide information on population trends. This analysis should follow on from previous investigations (Brouwer et al. 2023 SC-08-INFO-14) using the Cook Islands data but should be expanded to include all fleets.
The analysis should be stratified by fleet and area as a minimum and in addition, the series should be compared to that of Brandao et al. (2020) and Brouwer et al. (2023).
This project will also undertake an integrated stock assessment using the CPUE indices, length data (where appropriate), and age data from project ALF-2025-01.
Objectives:
- Meet with the SIOFA Alfonsino assessment Advisory Panel to discuss data input and potential assessment approaches.
- Develop standardised CPUE indices for alfonsino for the Eastern and Western stocks, including for different gears, targeting behaviour and vessel flag.
- Compare the indices to previously calculated CPUE indices. Provide comments on the recent trends in CPUE. Evaluate trends in length frequency and compare these to the CPUE trends.
- Review the previous stock assessments, all new information (including updated growth, maturity and acoustic data), and other relevant information to undertake an age structured production model to estimate the stock status of Alfonsino.
- The SIOFA interim reference points (Target = 40%B0 and Limit = 20%B0), and if SIOFA has not yet adopted final target and limit reference points, then a range of other reference points should be considered and estimates of stock status, fishing mortality and biomass should be provided in the terminal year of the assessment and over time including, at least but not limited to status in relationship to B40% and B20%, MSY, SBMSY, SB0, SBF=0, SB/SBMSY, SB/SBF=0, SB/SB0, F, FMSY, F/FMSY.
- Estimates of 20-year projected status (in 5-year intervals) under a range of future catch scenarios and appropriate estimates of future productivity (i.e., year class strengths)