Codworm - a possible biological indicator of the degree of mixing of Greenland and Iceland cod stocks (original) (raw)

Abstract

During a quantitative survey of the infestation of North Atlantic cod stocks with larvae of the codworm, Terranova decipiens Krabbe, considerable differences between the infestations of the various populations were observed. In particular, larvae were virtually absent from cod at Greenland and abundant in those at Iceland. However, on the spawning grounds off southwest Iceland, a reduction in the characteristic level of infestation of Iceland cod was noted. This was thought to be due to the immigration of uninfested cod from Greenland waters. An examination of the infestation in relation to the age of the host further supported this theory. The evidence suggests that the relative abundance of codworm might be used as a biological indicator, providing an aid to the determination of the relative proportions of Iceland and Greenland components of the cod population on the spawning grounds at southwest Iceland.

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Author notes

*Present address: The Boots Company Ltd, Thurgarton Research Station, The Priory, Thurgarton, Notts, NG14 7GX. England