Growth and
survival of first-feeding spotted wolffish (Anarhichas minor Olafsen)
at various temperature regimes
T.K. Hansen, I.-B. Falk-Petersen-2002
Aquaculture
Research,
33(14): 1119-1128
Abstract:
In order to define temperature regimes
that could benefit successful production of spotted wolffish (Anarhichas
minor) juveniles, experiments with offspring from two different females
were carried out. The larvae were fed a new formulated feed or a commercial
start-feed for marine fish, both of which have given high survival rates. In
the first experiment newly hatched larvae were fed at constant 6 °C, 8 °C,
10 °C and 12 °C as well as at ambient seawater temperature
(2.9-4.5 °C) during 63 days. High survival, 90% to 96%, was
registered at ambient and most constant temperature regimes, whereas in the
12 °C groups survival was reduced to 80%. Growth rate (SGR) was very
low, 1.8% day-1, at the low ambient temperatures. Growth rate was
positively correlated with temperature and varied between 3.1% day-1
to 4.7% day-1, from 6 °C to 12 °C. In the second
experiment, set up to include potential detrimental temperatures and study
beneficial effects of a more restricted, elevated first-feeding temperature
regime, the larvae were fed at constant 8 °C, 10 °C, 12 °C,
14 °C and 16 °C until 30 days post hatch, followed by
constant 8 °C for the next 33 days. In this experiment, low
survival, 25% and 2.0%, was registered at 63 days post hatch when
larvae were reared initially at 14 °C and 16 °C respectively.
The survival of the larvae at the other temperature regimes varied from 47%
to 64%, highest survival rate (64%) was found at 8 °C. The lowest
specific growth rate, 2.6% day-1, was noted in the 16 °C
group. At constant 8 °C to 14 °C (regulated to 8 °C), the
SGR varied from 4.45% day-1 to 5.13% day-1. The larvae
grew faster in the experiment when initially comparable temperatures (8 °C,
10 °C and 12 °C) were regulated to constant 8 °C after 30 days
compared with the first experiment where feeding was carried out at the same
constant temperatures (8 °C, 10 °C and 12 °C) during the
whole experimental period.
(Inger-Britt Falk-Petersen, Norwegian
College of Fishery Science, University of Tromsø, N-9037 Tromsø, Norway. E-mail: ingerf@nfh.uit.no)