Rearing of halibut larvae (Hippoglossus hippoglossis L.) to metamorphosis and beyond.

Abstract

A female halibut caught by gill-net was stripped and the eggs were imediately fertilized and incubated in the laboratory. About 50% of the eggs hatched when incubated in a refrigerator in stagnant water treated with antibiotics and with increased salinity. Of the about 1700 larvae kept in the refrigerator, about 35% were alive after 30 days, the temperature being about 5°C. The salinity of the water was about 37°/oo and was treated with antibiotics as before. A functional mouth started to develop 25 days after hatching. The last larvae in the refrigerator died on 5 May at an age of 60 days. At an age of 40 days larvae were transferred to a large basin in two black plastic bags with 50 larvae in each enclosure. In one of the plastic bags two of the halibut larvae survived and reached metamorphosis at the end of May at an age of 80-90 days and at a length of about 30 cm.