Biological parameters of immature, ripening, and non-reproductive, mature northeast Arctic cod in 1984–2006

• Published in: ICES Journal of Marine Science
• Main Author: Yaragina, Natalia A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Oxford University Press (OUP) 2010
• Subjects: Ecology; Aquatic Science; Ecology, Evolution, Behavior and Systematics; Oceanography; Arctic cod; Arctic; Barents Sea; Northeast Arctic cod
• Online Access: http://dx.doi.org/10.1093/icesjms/fsq059; http://academic.oup.com/icesjms/article-pdf/67/9/2033/29149946/fsq059.pdf

Abstract Yaragina, N. A. 2010. Biological parameters of immature, ripening, and non-reproductive, mature northeast Arctic cod in 1984–2006. – ICES Journal of Marine Science, 67: 2033–2041. Russian samples of cod caught in the Barents Sea during November–February, the period of migration to the overwintering and spawning grounds, were re-analysed by grouping the maturity stages recorded in three classes: immature, ripening, and apparently mature fish, with gonads of uncertain status. When treated by age class and gender, these three classes were characterized by significant differences in size (length and weight) and condition (somatic and a liver index). Within an age group, the group with uncertain status was on average consistently larger than the ripening fish and the latter group was on average larger than the immature component. However, in terms of condition, fish of uncertain status resembled the immature fish. Males and females displayed very similar patterns, although the levels were consistently lower for the former. The patterns are consistent with the interpretation that the gonads of uncertain status represent non-reproductive, mature fish. At the population level, the percentage of mature fish that presumably skip spawning varied annually between 4 and 21%, but this has little effect on the perception of the overall development in spawning-stock biomass. No correlation was found between the non-reproductive fraction and environmental factors examined.