Dramatic changes in spawning stock age-structure of Barents Sea cod ...

No abstracts are to be cited without prior reference to the author.Atlantic Cod (Gadus morhua) is one of the commercially most important fish species in the North Atlantic and plays a central role in several ecosystems. Fishing pressure has been heavy over a prolonged period and the recent decades h...

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Bibliographic Details
Main Authors: Ottersen, Geir, Hjermann, Dag Ø., Stenseth, Nils Chr.
Format: Article in Journal/Newspaper
Language:unknown
Published: ASC 2004 - K - Theme session 2024
Subjects:
Online Access:https://dx.doi.org/10.17895/ices.pub.25349413.v1
https://ices-library.figshare.com/articles/conference_contribution/Dramatic_changes_in_spawning_stock_age-structure_of_Barents_Sea_cod/25349413/1
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Summary:No abstracts are to be cited without prior reference to the author.Atlantic Cod (Gadus morhua) is one of the commercially most important fish species in the North Atlantic and plays a central role in several ecosystems. Fishing pressure has been heavy over a prolonged period and the recent decades have shown dramatic decline in abundance of many stocks. The Arcto-norwegian (northeast Arctic) cod stock in the Barents Sea is now the largest. We show that the age composition of the spawning stock has changed distinctly during the last 60 years, the average age of spawners has decreased from between 10 and 11 in the late 1940s to 7-8 now. Although less clear, there is also a tendency towards reduced age diversity in the spawning stock, fewer age classes now contributing. The trend towards a younger, less diverse spawning stock is worrying, in particular since earlier work by other authors has thoroughly documented that older Barents Sea cod produce disproportionately more and higher quality eggs than first-time ...