Joint NAFO/ICES Pandalus Assessment Working Group (NIPAG)

The Joint NAFO/ICES Pandalus Assessment Working Group (NIPAG) met to assess the Pandalus stocks in divisions 3.a and 4.a east and division 4.a west. The objective was to assess stock status and to draft advice. For divisions 3.a and 4.a east, advice is given according to the EU and Norway Long-Term Management Strategy (LTMS) based on annual TAC advice according to a TAC-year from 1 July to 30 June.

For shrimp in divisions 3.a and 4.a east, a length and age-based Stock Synthesis (SS3) statistical framework was used to assess the status of the stock based on updated input data. The assessment model was revised during the 2022 benchmark (ICES, 2022a) and new reference points were calculated at the LTMS evaluation in the 2023 Workshop on a long-term management strategy evaluation for the Northern shrimp (Pandalus borealis) in divisions 3.a and 4.a East (WKPANDLTMSE) (ICES, 2023a). The assessment model has a quarterly time step and contains hermaphroditic parameters, two areas, and six fleets. The model is also fit using a novel ensemble approach whereby three different age-varying natural mortality rates are considered. The assessment demonstrated that the fishing pressure on the stock is below F_target and F_pa and that spawning–stock size is below MSY B_trigger and B_lim.

In accordance with the new LTMS and new reference points, ICES advises that catches in the advice year 2025 (1 July 2025 to 30 June 2026) should be no more than 4 010 tonnes. This corresponds to a 12% reduction compared to the catch advice for assessment year 2024 (4 557 t). The further decrease in catch advice is linked to a downward revision in spawning stock biomass (SSB) in the most recent year. This was linked to higher-than-expected catch in assessment year 2023 (6 563 t), which exceeded both the scientific advice (5 125 t) and the TAC (6 076 t), and has removed a larger number of females from the population than was forecasted. This results in an F in 2023 that exceeded F_MSY and an SSB that is below B_lim on 1 July 2025.

The downward trend in stock size is compounded by a decrease in the survey index in assessment year 2024 (i.e. in January 2025), likely driven by the good 2021-year class having largely disappeared from the stock. A good recruitment class is, however, estimated in assessment year 2023 and is one of the highest in the last 20 years. As a short-lived species, the stock dynamics are driven by year class variation and this strong year class is already moving through the stock, causing increases in total biomass and exploited biomass in assessment year 2024. It is expected that this strong incoming year class will increase SSB. It is also notable that this year’s assessment was provided with updated data on Swedish discards in calendar year 2022 and 2023, and changes were made to how landings data are corrected to account for weight loss from boiling.

The SS3 model diagnostics of the assessment did not indicate any major issues with model fit; the model passed >75% of the model diagnostics considered. There is some evidence of retrospective bias in terms of SSB and F, which suggests a tendency to overestimate SSB and underestimate F. There is a high MASE hindcasting score for the survey in 4a east and further work will be needed to investigate this.

For shrimp in division 4a West (Fladen Ground), except for minimal landings from by-catches in the Danish fishery for Norway pout, no new information was available. Based on the precautionary approach, it was therefore advised to avoid any increase in fishing activity without comprehensive scientific monitoring. Furthermore, it was recommended to explore the IBTS as potential fisheries-independent data source to trace changes in stock abundance.