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Diet overlap between two subsequent year-classes of juvenile coastal cod ( Gadus morhua L.) and wild and reared cod

1992; Taylor & Francis; Volume: 77; Issue: 2 Linguagem: Inglês

10.1080/00364827.1992.10413496

1503-1128

Jarle Tryti Nordeide, Jan Helge Fosså,

Fish Ecology and Management Studies

Abstract Juvenile coastal cod (Gadus morhua) inhabit the sublittoral part of west Norwegian fjords. This paper analyses whether different co-occurring year-classes share food resources, during a period when food seemed scarce. Stomach contents were compared of the 1987 year-class and wild and reared cod of the 1988 year-class. To a large degree the three predator groups preyed upon the same prey groups, and also upon the same size-classes of Amphipoda, Portunidae and Teleostei. The similarities were higher between wild and reared cod of the same year-class, than between subsequent year-classes. Some differences in prey choice were found as wild and reared cod of the 1988 year-class ate more Copepoda, Amphipoda, Paguridae and less Portunidae and Teleostei than their one year older conspecifics. The stomachs of the 1987 year-class also included larger individuals of Portunidae and Teleostei than the one year younger cod. Possible competition between the year-classes and its implication in cod enhancement in fjords is discussed.