SOME OBSERVATIONS ON THE SEASONAL DISTRIBUTION OF DAB, LIMANDA-LIMANDA, IN THE SOUTHERN NORTH-SEA

The seasonal changes in the population structure of dab were observed in intervals of four to six weeks from January 1993 to November 1994 a t a fixed station northwest of Helgoland. The sex distribution was cha racterized by a reduced number of males during autumn and winter. In t he autumn of both years, an immigration of large females was evident. During long periods in spring and summer, the population structure rem ained relatively constant. The observations indicate that dab in the H elgoland region carry out a seasonal migration between coastal waters and the sampling area. Seasonal changes of the population structure oc curred at a relatively slow rate.