Spawning stock and recruitment in North Sea cod shaped by food and climate

In order to provide better fisheries management and conservation decisions, there is a need to discern the underlying relationship between the spawning stock and recruitment of marine fishes, a relationship which is influenced by the environmental conditions. Here, we demonstrate how the environment...

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Bibliographic Details
Published in:Proceedings of the Royal Society B: Biological Sciences
Main Authors: Olsen, Esben Moland, Ottersen, Geir, Llope, Marcos, Chan, Kung-Sik, Beaugrand, Grégory, Stenseth, Nils Chr.
Format: Article in Journal/Newspaper
Language:English
Published: The Royal Society 2010
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Online Access:http://dx.doi.org/10.1098/rspb.2010.1465
https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2010.1465
https://royalsocietypublishing.org/doi/full-xml/10.1098/rspb.2010.1465
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Summary:In order to provide better fisheries management and conservation decisions, there is a need to discern the underlying relationship between the spawning stock and recruitment of marine fishes, a relationship which is influenced by the environmental conditions. Here, we demonstrate how the environmental conditions (temperature and the food availability for fish larvae) influence the stock–recruitment relationship and indeed what kind of stock–recruitment relationship we might see under different environmental conditions. Using unique zooplankton data from the Continuous Plankton Recorder, we find that food availability (i.e. zooplankton) in essence determines which model applies for the once large North Sea cod ( Gadus morhua ) stock. Further, we show that recruitment is strengthened during cold years and weakened during warm years. Our combined model explained 45 per cent of the total variance in cod recruitment, while the traditional Ricker and Beverton–Holt models only explained about 10 per cent. Specifically, our approach predicts that a full recovery of the North Sea cod stock might not be expected until the environment becomes more favourable.