The use of behavioural observations in the larviculture of cold-water marine fish

Abstract

The use of behavioural observations on marine fish larvae has a long history and has added considerable depth to our understanding of the ecological adaptations of larval fish. In marine fish larviculture we are trying to domesticate wild animals. Behavioural observation, in conjunction with growth and survival information, is a powerful tool for understanding the behavioural adaptations of larvae. This paper reports on the results of experiments conducted on the first-feeding of two species of marine larvae. Results of experiments carried out on lumpfish ( Cyclopterus lumpus) fed the same density of live prey in pulses (twice or three times/day) or continuously, demonstrated that growth and feeding behaviour was significantly higher in the pulse treatments. A second set of experiments was performed on weaning of Atlantic wolffish ( Anarhichas lupus) larvae. Live prey and pelleted food were offered to larvae from the onset of first-feeding. Observations on larvae indicated that over the first few weeks, larvae fed mostly on live prey with some pellet feeding. This pattern changed as larvae grew and by eight weeks larvae fed mostly on pelleted feed. In this example, the behaviour of the larvae provided a schedule which could be used to wean wolffish from live prey to pellet food. Using this information, improvements of the rearing protocols of these species may now be made.