Larviculture of burbot (Lota lotaL.): larval rearing usingArtemiaand weaning onto dry feed

Abstract

The burbot (Lota lota) is the only gadoid fish in freshwater and could be an interesting candidate for an aquaculture production. The objective of this study was to develop suitable rearing techniques for early life stages of burbot larvae under intensive rearing conditions. Burbot larvae were reared with live food (Artemia salina nauplii) whilst the effects of different photoperiods (24 h light and 12 h light) and ration level on growth and survival of the larvae were investigated from 7 to 56 days posthatching (dph). Larvae reared under continuous light survived (45.4%) and grew better [specific growth rate (SGR): 7.9 % day−1] than under 12 h light (34.2% respectively 7.1 % day−1). Rearing burbot larvae with three different ration levels [20–80 (I), 40–160 (II) and 80–320 (III) Artemia per larva per day] resulted in a clear relationship between food availability and larval performance [SGR: 8.1 (I), 9.2 (II) and 10.0 (III) % day−1]. Burbot larvae were weaned from Artemia onto two commercial microparticulate diets (MPD). Two different particle sizes of MPD 1 (AGLONORSE) and MPD 2 (START) were introduced on 35 and 56 dph. The two weaning experiments were conducted independently of one another. The MPD 2 was not accepted at all, thus none of the larvae survived. Feeding of MPD 1 from 56 to 91 dph resulted in better growth (SGR: 9.7 % day−1) and survival rate (13.5%) as distinct from 35 to 70 dph (SGR: 4.6 % day−1, survival rate: 10.5%). The results of our study indicate the potential of the burbot for a successful commercial larviculture in the future.