Vertical Distribution of Atlantic Halibut (Hippoglossus hippoglossus) Eggs

Abstract

It is suggested that the vertical distribution of Atlantic halibut (Hippoglossus hippoglossus) eggs is determined by their specific density and that it is closely correlated to seawater salinity. In two deep North Norwegian fjords, only one halibut egg was found near the bottom (approximately 5200 m3 seawater filtered), while 278 eggs were found floating pelagically in intermediate water layers (approximately 190 000 m3 seawater filtered). Eggs were most abundant in water masses where temperature and salinity ranged between 4.5 and 7.0 °C and 33.8 and 35 0‰. Neutral buoyancy salinity measurements of living eggs corresponded approximately with the observed capture salinities. Mean capture salinity was 34.2 ± 0.3‰ (Malangen) and 34.5 ± 0.4‰ (Sørøysund). Egg diameters ranged from 3.06 to 3.49 mm.