The transfer of Atlantic salmon ( Salmo salar) with constricted yolk sacs to an artificial hatching substrate

Abstract

Atlantic salmon alevins were transferred from a flat screened hatching tray to an artificial hatching substrate when all larvae had developed yolk sac constrictions. The growth rate and the yolk absorption rate of the larvae increased after the transfer. When the larvae were transferred at an early stage, the yolk behind the constrictions was absorbed normally, showing that yolk sac constrictions are not an irreversible injury but rather a condition which is formed and maintained through high larval activity.