Harvest selection on Atlantic cod behavioral traits: implications for spatial management

Authors

  • Esben Moland Olsen,

    1. Institute of Marine Research Flødevigen, N-4817 His, Norway
    2. Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biology, University of Oslo, P.O. Box 1066 Blindern, N-0316 Oslo, Norway
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  • Michelle R. Heupel,

    1. Australian Institute of Marine Science, Townsville, Queensland 4811, Australia
    2. Fishing and Fisheries Research Centre, School of Earth and Environmental Sciences, James Cook University, Townsville, Queensland 4811, Australia
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  • Colin A. Simpfendorfer,

    1. Fishing and Fisheries Research Centre, School of Earth and Environmental Sciences, James Cook University, Townsville, Queensland 4811, Australia
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  • Even Moland

    1. Institute of Marine Research Flødevigen, N-4817 His, Norway
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  • Supported by the Norwegian Research Council.

Esben Moland Olsen, Institute of Marine Research Flødevigen, N-4817 His, Norway. Tel: +47 37059029; Fax: +47 37059001; E-mail: esben.moland.olsen@imr.no

Abstract

Harvesting wild populations may contrast or reinforce natural agents of selection and potentially cause evolutionary changes in life-history traits such as growth and maturation. Harvest selection may also act on behavioral traits, although this field of research has so far received less attention. We used acoustic tags and a network of receivers to monitor the behavior and fate of individual Atlantic cod (Gadus morhua, N= 60) in their natural habitat on the Norwegian Skagerrak coast. Fish with a strong diel vertical migration, alternating between shallow- and deep-water habitats, had a higher risk of being captured in the fishery (traps, gillnet, hand line) as compared to fish that stayed in deeper water. There was also a significant negative correlation between fish size (30–66 cm) and the magnitude of diel vertical migration. Natural selection on behavior was less clear, but tended to favor fish with a large activity space. On a monthly time scale we found significant repeatabilities for cod behavior, meaning that individual characteristics tended to persist and therefore may be termed personality traits. We argue that an evolutionary approach to fisheries management should consider fish behavior. This would be of particular relevance for spatial management actions such as marine reserve design.

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