Blar i Fiskeridirektoratets skrifter, Serie Havundersøkelser (1900-1990) på forfatter "Dragesund, Olav"
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Comparative analysis of year-class strength among fish stocks in the North Atlantic
Dragesund, Olav (Fiskeridirektoratets skrifter, Serie Havundersøkelser, Research report, 1971)A comparative analysis of year-class strength among stocks of abundant fish species (herring, cod, haddock, saithe, redfish and capelin) in the North Atlantic is given with a view to discussing whether covariation in ... -
Distribution, abundance and mortality of young and adolescent Norwegian spring spawning herring (Clupea harengus Linné) in relation to subsequent year-class strength
Dragesund, Olav (Fiskeridirektoratets skrifter, Serie Havundersøkelser, Research report, 1970)1. The distribution of young and adolescent herring in coastal and offshore waters of northern Norway has been investigated for the 1959- 1965 year-classes by combined acoustic surveys and fishing experiments. 2. In the ... -
Estimates of stock size and reproduction of the Barents Sea capelin in 1970-1972
Dragesund, Olav; Gjøsæter, Jakob; Monstad, Terje (Fiskeridirektoratets skrifter, Serie Havundersøkelser, Research report, 1973)DRAGESUND, O., GJØSÆTER, J. and MONSTAD, T. 1973. Estimates of stock size and reproduction of the Barents Sea capelin in 1970-1972. FiskDir. Skr. Ser. HavUnders., 16: 105-139. The distribution and migration of young ... -
Factors influencing year-class strength of Norwegian spring spawning herring (Clupea harengus Linné)
Dragesund, Olav (Fiskeridirektoratets skrifter, Serie Havundersøkelser, Research report, 1970)1. Variation in year-class strength of Norwegian spring spawning herring is analysed in relation to the structure and the size of the spawning stock, the location and the time of spawning and environmental conditions during ... -
Norwegian tagging experiments in the north-eastern North Sea and Skagerak, 1964 and 1965
Dragesund, Olav; Haraldsvik, Steinar (Fiskeridirektoratets skrifter, Serie Havundersøkelser, Research report, 1968)1. Norwegian herring tagging experiments carried out with internal metal tags in Skagerak in 1964 and 1965 are described. 2. The returns from these taggings up to 31 October 1966 are reviewed and factors affecting the ... -
A Note on the Effect of Electric Fields on Gadus virens
Dragesund, Olav; Leivestad, Helge (Fiskeridirektoratets skrifter, Serie Havundersøkelser, Research report, 1959)To test electrotaxis earlier experiments have been performed in relatively small tanks. It was felt, therefore that the arrangement with a comparatively big tank would give greater allowance for a more varied behaviour ... -
On the possibility of estimating year-class strength by measuring echo-abundance of 0-group fish
Dragesund, Olav; Olsen, Steinar (Fiskeridirektoratets skrifter, Serie Havundersøkelser, Research report, 1965)The possibility of estimating the distribution and abundance of 0-group fish by a combination of echo surveying and fishing experiments with pelagic trawl and purse seine is discussed. The existence of scattering layers, ... -
Stock size fluctuations and rate of exploitation of the norwegian spring spawning herring, 1950-1974
Dragesund, Olav; Ulltang, Øyvind (Fiskeridirektoratets skrifter, Serie Havundersøkelser, Research report, 1978)Stock size fluctuations and rate of exploitation of the Norwegian spring spawning herring, 1950-1974. FiskDir. Skr. Ser. HavUnders., 16: 315-337. The collapse of the Norwegian spring spawning herring stock is described, ...