Dominating sublittoral fish species in a west Norwegian fjord and their trophic links to cod (Gadus morhua L.)
Peer reviewed, Journal article
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The fish fauna in the sublittoral habitat of Masfjorden, western Norway, has been studied in order to reveal survival and growth prospects of released juvenile cod in a large-scale stock enhancement experiment. Seasonal changes in abundance of dominating fish species and in the diet of potential competitors and predators to juvenile cod were emphasized. A total of 44 species from 17 families of Teleostei and 4 families of Chondrichthyes were recorded at 5-20 m depth of the sublittoral of Masfjorden. Gadids were dominating (50.2 % by numbers, 10 species) and saithe (Pollachius virens), pollack (P. pollachius), poor-cod (Trisopterus minutus) and cod (Gadus morhua) were most numerous. Labrids form a second dominating family (44.7 % by numbers, 5 species) of which Centrolabrus exoletus, Ctenolabrus rupestris, Labrus bimaculatus and L. bergylta were the most abundant. Pollack and saithe had highest abundance during summer and autumn. The labrids and poor-cod had maximum abundance in summer. All labrids, pollack and saithe showed minimum abundance in winter while poor-cod had lowest abundance in spring and highest in summer. Dietary studies showed that gobies were one of the major preys for small individuals of cod, pollack, saithe and poor-cod in the summer and autumn. Gadids and labrids were important prey for large cod and pollack.