Comparative analysis of year-class strength among fish stocks in the North Atlantic

Abstract

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 year-class strength exists among species living in the same region and among stocks of the same species in different regions. It is suggested that fish stocks of the same species living in regions distinctly separated from each other are independent and apparently no covariation in year-class strength exists among them. Even in neighbouring regions no apparent covariation could be found. Not all the species living in the same region produce numerous broods in the same year. Indications were found that the total number of 0-group fishes produced varied from year to year. It is tentatively concluded that the variation in total 0-group abundance did not vary to the same extent as the variation of the abundance of each of the species.