Early development of Northeast Arctic greenland halibut (Reinhardtius hippoglossoides)

Abstract

The early development of the Greenland halibut (Reinhardtius hippoglossoides) has never been described in detail. This study contains some preliminary notes on the egg development of the Northeast Arctic Greenland halibut Buoyancy and morphometric characteristics are compared with field sampled eggs, in order to identify these to species. The eggs in the ovary of ripening females were large (about 4 mm), transparent, almost equal in size and stuck to the walls of the ovary. In ripe, artificially spawned females the ovulated eggs were all easily released in one batch. This may indicate that Greenland halibut has a comparatively long period between each egg batch delivered. Artificially spawned eggs of the Greenland halibut were 3.3-4.2 mm and had neutral buoyancy in seawater of ca 33 °/oo during the first four days of development. During gastrulation the egg density increased until closure of blastopore. Eggs from field surveys had neutral buoyancy in seawater densities near 1.0279 g/cm3. This density is found at depths around 650 meters (34.9 °/oo S and 1.8° C) in the spawning area. The eggs hatched after nearly two months incubation. The embryo seems to hatch at an apparently premature stage.