The decision to revise the advice already issued in June this year for the 2025 Northern Shelf cod fishery is due to an error detected in the multi-stock stochastic forecasting model used for the advice in 2024 and 2025.
As a result, the combined catch advice for all three substocks (Northwestern, Viking, and southern) is now 15,511 tonnes, revised down from the original figure of 19,321 tonnes.
According to ICES, this does not affect the stock assessment model fit – only the forecast is affected.
‘The main reason for this lower forecast is that the model predicts higher levels of natural mortality. As a result, fishing must be reduced even more – especially for the southern substock – to help rebuild it to a safe population level above the biomass limit, Blim,’ ICES states, adding that during their meeting this October, the ICES Mixed Fisheries Working Group (WGMIXFISH) identified discrepancies in the forecasting parameters for Northern Shelf cod.
‘Quality assurance is central to ICES advice and a key part of our Advisory Plan. ICES is committed to continuously improving this process. The forecasting model for Northern Shelf cod now includes key diagnostic parameters as standard outputs. We will enhance the expert group audit process to include independent catch forecasts, such as those by WGMIXFISH. This will be made easier with broader adoption and improved standardization of tools and diagnostics in ICES Transparent Assessment Framework (TAF),’ ICES states.
