© 1987 by ICES/CIEM International Council for the Exploration of the Sea/Conseil International pour l'Exploration de la Mer
Spawning season of the Atlantic halibut (Hippoglossus hippoglossus) in northern Norway
Institute of Biology and Geology, University of TromsØ P.O. Box 3085 Guleng, N-9001 Tromsø, Norway
Department of Marine Biology, Tromsø Museum, University of Tromsø P. O. Box 2550, N-9001 Tromsø, Norway
Institute of Marine Research, Directorate of Fisheries P.O. Box 1870, N-5011 Bergen—Nordnes, Norway.
The spawning season of the Atlantic halibut (Hippoglossus hippoglossus) was examined by studying maturity stages in adult fish in Sørøysund, Finnmark, and in Salten/ Folda, Nordland, during 1956–1960, and by sampling eggs from the plankton in Malangen, Troms, during 1983–1986. These three sites are well-known spawning grounds for the species in northern Norway.
On the basis of gonad maturity studies the main spawning in Sørøysund was between 20 January and 15 February. Year-to-year variations were small. In Salten/ Folda, however, spawning was later, with intensive spawning occurring throughout February.
In Malangen, halibut eggs were found in the plankton from late December to late March. The relative occurrence of young eggs (blastulae, 0–3 days old) indicated a peak in spawning activity in late January and early February. The mean diameter of the eggs seemed to decrease during the latter part of each spawning season.