Alders-lengdeforhold for kysttorsk i fangster fra Mørekysten

Abstract

Data from cod taken by Danish seine and fish-pots off Sunnmøre and Nordmøre in the years 1969, 1979 and 1980 are analysed. Three groups of coastal cod living separately, was found at Sunnmøre: The first consisted of mature cod (mainly 4 years and older), the second of big immature fish (dominated by 3 years old fish) and the third of small cod (2-3 years old). Some overlapping in the age distributions between the various groups were observed. However, the mean length of an yearclass decreased from group one to group three. Consequently the size more than the age is supposed to be the decisive grouping factor. The lowest mean length for the various age groups were observed at Nordmøre. A higher concentration on the small-fish-size groups of the fish-pot fishery compared with the Danish seine fishery are suggested the most likely reason.