DOMINATING SUBLITTORAL FISH SPECIES IN A WEST NORWEGIAN FJORD AND THEIR TROPHIC LINKS TO COD (GADUS-MORHUA L)

The fish fauna in the sublittoral habitat of Masfjorden, western Norwa y, has been studied in order to reveal survival and growth prospects o f released juvenile cod in a large-scale stock enhancement experiment. Seasonal changes in abundance of dominating fish species and in the d iet of potential competitors and predators to juvenile cod were emphas ized. A total of 44 species from 17 families of Teleostei and 4 famili es 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 (Tri sopterus minutus) and cod (Gadus morhua) were most numerous. Labrids f orm 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 abu ndance during summer and autumn. The labrids and poor-cod had maximum abundance in summer. All labrids, pollack and saithe showed minimum ab undance in winter while poor-cod had lowest abundance in spring and hi ghest in summer. Dietary studies showed that gobies were one of the ma jor preys for small individuals of cod, pollack, saithe and poor-cod i n the summer and autumn. Gadids and labrids were important prey for la rge cod and pollack.