Bunnfiskundersøkelser i Nord-Norge og Barentshavet første halvår 1970

Abstract

In the present report is given an account of field work with preliminary results of investigations on demersal fish species during the first months of 1970 in northern Norway and in the Barents Sea. The report is primarily concerned with the spawning migration of Arctic cod to the Lofoten area, the distribution of cod, haddock and redfish during spring in the Barents Sea, length and age distributions of bottom trawl catches by research vessels and commercial long line catches. The migration of Arctic cod to the Lofoten area and the distribution of cod in the spawning area were investigated by several echo surveys from the middle of January to the end of April. Cod occurred in the spawning area in the first days of February, spawned during March and April, and disappeared in the second half of April. Higher abundance of spawning cod was recorded in 1970 than in the previous years. The 1963 year-class, which .spawned for the first time in 1970, dominated the commercial long line catches in the Lofoten area, while both the 1964 and the 1963 year-classes were strongly represented in the commercial catches along the coast off Troms and western Finnmark. Commercial catches of coastal cod from the same areas were dominated by the 1963 and 1964 year-classes. Demersal fish species were consentrated in May off the Finnnark coast. Bottom trawl catches taken by R.V. «Johan Hiort» in these areas were composed of cod, haddock, coalfish, redfish and long rough dab. The relative quantities of the different species varied greatly between hauls. However, cod, coalfish and redfish made up the main part of the catches from the western area while cod and haddock were the dominatin species in catches from the coastal areas. A great part of the cod were more than 50 cm, and the 1964 year-class was dominating. The 1969 year-class was fairly well represented in trawl catches from eastern Finnmark and the southern Barents Sea while the year-classes 1966—1968 were only represented by smaller numbers. The experimental trawl catches of haddock from the Finnmark coast and the Barents Sea were dominated by the 1969, the 1967 and 1964 year-classes.