Workshop on a long-term management strategy evaluation for the Northern shrimp (Pandalus borealis) in divisions 3.a and 4.a East (Skagerrak and Kattegat and northern North Sea in the Norwegian Deep) (WKPANDLTMSE) ...

• Main Author: ICES
• Format: Report
• Language: English
• Published: ICES Scientific Reports 2024
• Subjects: Fisheries and aquaculture; Pressures, impacts, conservation, and management; Greater North Sea ICES Ecoregion; Kattegat; Tac; northern shrimp; Pandalus borealis
• Online Access: https://dx.doi.org/10.17895/ices.pub.22434577.v1; https://ices-library.figshare.com/articles/report/Workshop_on_a_long-term_management_strategy_evaluation_for_the_Northern_shrimp_Pandalus_borealis_in_divisions_3_a_and_4_a_East_Skagerrak_and_Kattegat_and_northern_North_Sea_in_the_Norwegian_Deep_WKPANDLTMSE_/22434577/1

Our objectives were to evaluate the impacts of: changing the timing of the assessment from a calendar-year to a mid-year (1 July–30 June); and moving to a fixed 12-month TAC with one advice per year. The key question addressed is whether these changes would result in advice that is in line with the long-term management strategy (LTMS) for the stock. We report how the data and assessment were shifted to match the proposed TAC year; and detail a short-cut MSE used to evaluate these changes with respect to the LTMS.Shifting the model year resulted in similar historical trends to the previous assessment but resulted in changes to key parameters, including the hermaphroditic transition rates and stock-recruit steepness. The hermaphroditic inflection age was estimated to increase and resulted in substantial reduced abundance of age 2 females. This reduced spawning stock biomass and had a knock-effect of producing unrealistically high steepness values.We fixed hermaphroditic parameters to empirical values and ...