REPRODUCTION, SPAWNING BEHAVIOR AND CAPTIVE BREEDING OF THE COMMON WOLFFISH ANARHICHAS-LUPUS L

The reproductive biology and spawning behaviour of the common wolffish (Anarhichas lupus) was studied in the laboratory, and various facilit ies were tested in order to make common wolffish spawn in captivity. F ish caught on the south and west coast of Norway spawned between the m iddle of October and the middle of February, with a peak around the tu rn of the year. There is no sexual dimorphism in common wolffish prior to maturation. Towards spawning the ripening female adopts a pronounc ed pot-bellied shape. The testis is small, on average only 0. 11% of t he total body weight of males, and there is little difference in the s ize of running-ripe and non-running testes. At most 1.5 ml of milt was stripped from a running male, and males were found to be running duri ng most of the spawning season. Running males have a papilla on their urogenital pore which may serve as a copulatory organ. Morphological a s well as behavioural evidence strongly suggests that the eggs of the common wolffish are fertilized internally, and that copulation takes p lace 8-15 h before spawning. No successful, natural spawning took plac e in the various facilities tested, ranging from small tanks (4 m2) wi th single pairs to big basins (up to 1500 m2) with many wolffish prese nt. The common wolffish seems to have a complex reproductive behaviour which probably makes it difficult to obtain natural spawning on a reg ular basis in captivity. Procedures are suggested for artificial ferti lization of common wolffish eggs.