Reproductive strategy, egg characteristics and embryonic development of Greenland halibut (Reinhardtius hippoglossoides)

Despite the commercial importance of Greenland halibut (GH), important gaps exist in our knowledge of the reproductive and early life stage biology for this species. The present study examined through laboratory experiments the spawning strategy, realized fecundity, egg characteristics, biochemical composition, and embryonic development of GH. The results confirmed the hypothesis that GH is a single-batch spawner producing large eggs, resulting in low realized fecundity. Embryonic development and hatching time are highly dependent on incubation temperature; 50% hatching occurred after 46, 30, and 24 days at 2, 4, and 6 degrees C, respectively. Few changes in the biochemical composition of the eggs are observed during embryonic development. Newly hatched larvae are not well developed, having a large yolk sac, no pigmentation and incomplete development of the jaws. Egg specific density confirmed the mesopelagic distribution of the eggs at sea. However, important buoyancy changes occurring in the last 3-4 days before hatching indicate that larvae hatch higher in the water column. These results are important for understanding advection and dispersion processes of GH eggs and larvae and the connectivity between spawning grounds and nursery areas.