Distribution of mackerel eggs and larvae in the Skagerrak, 1957-1959

Abstract

Numbers of mackerel eggs and larvae collected from 495 vertical hauls at 269 stations in the Skagerrak and Oslofjord, 1957-59 are analysed. Eggs were found in practically all areas of the Skagerrak during the sampling period: from the middle of May to the beginning of July. A few larvae, but very few if any eggs, were probably taken from below a depth of 50 m. Early in the season spawning seems to take place mainly in the comparatively warm waters of low salinity in the Baltic Current. In 1959 spawning started about mid-May, in 1957 and 1958 in the last days of May; in 1959 May surface temperatures were higher than in the two preceding years. Spawning seems to take place mainly in water temperatures of 10-16°C.