Year-round genetic monitoring of mixed-stock fishery of Atlantic cod (Gadus morhua); implications for management

Helle Torp Christensen, Frank Rigét, Anja Retzel*, Erik Haar Nielsen, Einar Eg Nielsen, Rasmus Berg Hedeholm

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Abstract

Mixed-stock fisheries pose a challenge for fisheries management recommendations and management, as mixed stocks can lead to unintentional over- or under-exploitation of stocks, with both short- and long-term biological and economic consequences. This study demonstrates practical application and implementation of year-round high-resolution genetic stock monitoring in management of mixed Atlantic cod (Gadus morhua) stocks in western Greenland. Using a panel of 96 high resolution gene-associated SNPs, we identified the stock of origin for four cod stocks in the two major inshore mixed-stock fisheries. Contribution of individual stocks was quantified to identify if fjord sections, times of year, and fish size, would allow a “clean fishery” with a minimal contribution of the depleted West Greenland Offshore (WGO) population. High level of mixing was identified with 50% of inshore catches originating from the inshore stock, 20% from the East Greenland/Iceland offshore stock, and 30% from the WGO stock. Although some spatiotemporal variation of stock proportions was identified, a practice allowing exclusively fishing a specific stock was not possible. Accordingly, we demonstrate the need to allocate catches at the biological stock level and show that application of high-resolution genetics is a reliable and necessary tool.
Original languageEnglish
Article numberfsac076
JournalICES Journal of Marine Science
Volume79
Issue number5
Pages (from-to)1515-1529
Number of pages15
ISSN1054-3139
DOIs
Publication statusPublished - 2022

Keywords

  • DNA
  • Fisheries management
  • Fishery
  • Migration
  • Mixed stocks

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