Cod recruitment is strongly affected by climate when stock biomass is low

Abstract Stocks of Atlantic cod (Gadus morhua) have been declining over much of the North Atlantic for the past 30 years, owing to a combination of overfishing and adverse changes in their environment. In a previous study, environmental effects were introduced as an extra parameter in the stock-recr...

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Bibliographic Details
Published in:ICES Journal of Marine Science
Main Author: Brander, Keith M.
Format: Article in Journal/Newspaper
Language:English
Published: Oxford University Press (OUP) 2005
Subjects:
Online Access:http://dx.doi.org/10.1016/j.icesjms.2004.07.029
http://academic.oup.com/icesjms/article-pdf/62/3/339/29151161/62-3-339.pdf
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Summary:Abstract Stocks of Atlantic cod (Gadus morhua) have been declining over much of the North Atlantic for the past 30 years, owing to a combination of overfishing and adverse changes in their environment. In a previous study, environmental effects were introduced as an extra parameter in the stock-recruit relationship, where they act as a multiplier, independent of the level of spawning-stock biomass (SSB). Using a non-parametric pooled analysis of all cod stocks on the European Shelf south of 62°N, it is shown here that environmental variability (as represented by the North Atlantic Oscillation) only has a significant effect on recruitment when the spawning stock is low. This has implications for fisheries management strategies, and for rates of stock recovery, which will be very dependent on environmental conditions.