The effect of ambient salinity on the buoyancy of eggs from the Atlantic halibut (Hippoglossus hippoglossus)

Abstract

The effect of ambient salinity on buoyancy and the formation of perivitelline fluid in eggs from the Atlantic halibut Hippoglossus hippoglossus have been investigated. The results clearly demonstrate that the water balance of the eggs are independant of the ambient salinity the first days after fertilization. The water loss from eggs fertilized in 17 ppt saline sea water was not less than from eggs fertilized in 34 ppt sea water in spite of a reduced osmotic gradient. Neither was the egg buoyancy altered by fertilization in low saline sea water. For proper fertilization, the eggs from the Atlantic halibut need concentrations of calcium near the concentration found in sea water.