Maturity classes and spawning behaviour of Greenland halibut ( Reinhardtius hippoglossoides)

The maturation and spawning of Greenland halibut ( Reinhardtius hippoglossoides Walbaum) is described from six trawl surveys in the spawning area along the continental slope between North-Norway and Svalbard from October 1997 to May 1998. Different maturity classes were identified with frequency analyses of logarithmic classes of the Gonadosomatic Index. The main spawning period started in November, peaked in December and ended in late January. Mature females appeared at the spawning area in the early autumn and left during the first months of the year. Males were recorded after this with residual milt, indicating that some spawning may occur several months after the main spawning season. Observations from the fishery indicated spawning concentrations near the coast half a year after the main spawning period. Sex differences in spawning behaviour were discussed and related to the problem of representative sampling.