Distribution and abundance of post larval Northeast Arctic cod and haddock

Abstract

From 1977 onwards an annua1 postlarvae survey has been carried out off northern Norway in June/July. The aim is to study the distribution of fish larvae, and to establish an index for thom 53m to surface. In 1983 the station grid was designed to study mesoscale features of the larval distribution. It was found that cod larvae were mainly confined to coastal water masses and haddock larvae to the Atlantic water masses. The mesoscale circulation was found to influence the larval distribution. The same features were also found for the years 1980 and 1981. In 1979 the larval distribution was different, and the reason for this is discussed. From 64 to 84% of the cod larvae were found in the upper 13 m. The vertical distribution indicates no die migration, and no difference of the vertical distribution for the different in length groups was found, The mean length of the cod larvae was highest in 1983, indicating good feeding conditions this year.Indications of a high larval mortality from June to September in 1981 are discussed. The denser station grid introduced in 1983 gives probably a better quantitative index than the station grid used the previous years.