A preliminary report on the natural occurrence and ecology of Atlantic halibut (Hippoglossus hippoglossus) postlarvae and young immature stages

Abstract

Surveys designed to capture Atlantic halibut, Hippoglossus hippoglossus, postlarvae and young immatures were carried out around Sørøya in North Norway in 1985, 1986 and 1987. Hydrographical conditions and the current features in the area were also investigated. The ichthyoplankton trawls (MOCNESS, Tucker-trawl) filtered more than 200.000 m3 of sea water in the March months. Only one single pelagic postlarvae, 11.9 mm long and in a stase of first feeding, was captured, near the center of a cyclonic vortex in Sørøysundet. Most probably, the filtering capacity of the equipment used was too low given the low concentrations in which halibut larvae seem to occur. Trawling with a pelagic trawl in May yielded no pelagic postlarvae. The shallow (20-60 m) area north of sørøya act as a halibut nursery area where considerable amounts of young, immature fish aged 2-4 years are found.