Article,
Mixed-stock analysis of Atlantic herring (Clupea harengus): a tool for identifying management units and complex migration dynamics
Affiliations
- [1] Tech Univ Denmark, Natl Inst Aquat Resources, DK-2800 Lyngby, Denmark [NORA names: DTU Technical University of Denmark; University; Denmark; Europe, EU; Nordic; OECD];
- [2] Inst Marine Res IMR, POB 1870 Nordnes, N-5018 Bergen, Norway [NORA names: Norway; Europe, Non-EU; Nordic; OECD];
- [3] Thunen Inst Baltic Sea Fisheries, D-18069 Rostock, Germany [NORA names: Germany; Europe, EU; OECD];
- [4] Swedish Univ Agr Sci, Dept Anim Breeding & Genet, SE-75007 Uppsala, Sweden [NORA names: Sweden; Europe, EU; Nordic; OECD];
- [5] Univ Tartu, Parnu Coll, Ringi 35, EE-80012 Parnu, Estonia [NORA names: Estonia; Europe, EU; OECD];
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Abstract
We developed and validated a mixed-stock analysis (MSA) method with 59 single-nucleotide polymorphisms selected from genome-wide data to assign individuals to populations in mixed-stock samples of Atlantic herring from the North and Baltic seas. We analysed 3734 herring from spawning locations and scientific catches of mixed feeding stocks to demonstrate a "one-fits-all" tool with unprecedented accuracy for monitoring spatio-temporal dynamics throughout a large geographical range with complex stock mixing. We re-analysed time-series data (2002-2021) and compared inferences about stock composition with estimates from morphological data. We show that contributions from the western Baltic spring-spawning stock complex, which is under management concern, have likely been overestimated. We also show that a genetically distinctive population of western Baltic autumn spawners, ascribed low fisheries importance, contributes non-negligible and potentially temporally increasing proportions to mixed-stock aggregations, calling for a re-evaluation of stock definitions. MSA data can be implemented in stock assessment and in a variety of applications, including marine ecosystem description, impact assessment of specific fleets, and stock-rebuilding plans.