Long-term changes in age at sexual maturity of the northeast Arctic cod (Gadus morhua L.)
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http://hdl.handle.net/11250/104511Utgivelsesdato
1988Metadata
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This report is not to be cited without prior reference to the authorSammendrag
Maturity ogives of the Northeast Arctic cod for the year
classes 1932 to 1976 were computed based on age and number of
spawning zones in otoliths of cod caught on the spawning
grounds at Lofoten. A reduction in the median age at maturity
of approximately 2,5 years over the period is indicated. A
similar reduction in mean age of the spawning stock was found.
Males generally mature at a lower age than females, but the
difference has become smaller over the period studied. The
decline in median age at maturity is most marked for the year
classes after 1950. A compensatory response to the demographic
changes could explain the decline. Genetic changes as a
result of selective fishing is also possible, but cannot be
evaluated from the present data.