State-dependent spawning migration in Norwegian spring-spawning herring |
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Authors: | A. Slotte,&Dagger Ø . Fiksen,&dagger |
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Affiliation: | Institute of Marine Research, P.O. Box 1870 Nordnes, N-5817 Bergen, Norway;Department of Fisheries and Marine Biology, University of Bergen, Bergen High Technology Centre, N-5020 Bergen, Norway |
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Abstract: | Norwegian spring-spawning herring Clupea harengus winter in fjords of northern Norway, whereas the subsequent spawning occurs at various locations along the coast with a main bulk off the south-western coast. The distance of the southward spawning migration tends to increase with the length and condition of the fish. The costs and benefits of the southward migration were modelled in terms of fitness (number of surviving offspring). The model assumes that larvae have increasing growth and survival rates further south as they pass through warmer water during the northward drift in the coastal current. In agreement with the observed spawning distribution, optimal spawning grounds were predicted off the southwestern coast and farther south with increasing fish length and condition. The present study suggests that homing is not a successful strategy for these herring, and instead the selection of spawning grounds depends on individual internal state (length, condition), the cost of migration and the probability of larval survival. |
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Keywords: | herring migration spawning larvae temperature fitness |
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