Investigations on Eggs and Larvae of Commercial Fishes in Norwegian Coastal and Offshore Waters in 1957-58
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The size frequencies of cod and haddock eggs, sampled in coastal and offshore waters of northwestern Norway have been studied. Within the same species, variations in the mean size of the eggs have been observed, as well as differences in the mean size between eggs of cod and haddock. During the years 1951-58 the cod eggs at Skrova in the Lofoten area decreased in mean size during the spawning season. Following HEINCKE & EHRENBAUM (1900), the size variations are thought to be partly related to decreasing egg size in the individual fish during the spawning season, partly to decreasing size of the fish from the beginning to the end of the same season. In 1957 cod eggs and larvae were relatively scarce at Skrova, but in 1958, - abundant. Length measurements of cod fry taken in a high sped net at varying depths near Skrova in June 1957 indicate that the smaller fry as a rule keep to greater depths. In April 1957 fish eggs, probably of haddock, were moderately abundant along the edge off Lofoten and Vesterålen. In April-May 1958 haddock eggs and larvae were mainly found east of Shetland and off Vesterålen, some also west of the Halten Bank. Cusk eggs were distributed within the 400 m contour from Shetland to the north of Andenes. Saithe larvae were mainly taken on Tampen, off Stadt, and on the Halten Bank. In May 1957 herring larvae were taken in moderate numbers on the coast banks from Ona to Træna, a few also farther north. In June larger herring fry were relatively numerous in the same areas, in the Vestfjord, and on the coast banks farther north. The mean length of this herring decreased southwards from Vesterålen to Møre. In April-May 1958 small herring larvae were abundant northeast of Shetland, off Stadt, and on the Halten Bank. From the end of May to the second half of June larger herring fry (13-42 mm) were taken in numbers from off Vesterålen and southwards. Thc abundance of redfish larvae in coastal and offshore waters of northern Norway has been studied, and average figures are given for a series of years. In May-June 1958 redfish larvae were abundant in the same waters, especially outside the edge from Andenes and northwards. The western limit of the distribution of the redfish larvae in the Norwegian Sea coincides with that given by BARANENKOVA et al. (1957). Length measurements indicate an increase in the mean size of the redfish larvae from about 9 mm at the beginning of June to near 20 mm in coastal areas in August.
SeriesFiskeridirektoratets skrifter, Serie Havundersøkelser
vol 12 no 7