The
influence of rearing temperature on early development and growth of spotted
wolffish Anarhichas minor (Olafsen)
-2001
Aquaculture Research, 32(5): 369-378
Abstract:
Temperature influenced the developmental rate,
survival and early growth of eggs and embryos of spotted wolffish, Anarhichas
minor (Olafsen), an interesting candidate for cold water cultivation.
The total incubation period decreased from 220 days at 4 °C (880 daydegrees),
to 177 days at 6 °C (1062 daydegrees) and 150 days at 8 °C
(1200 daydegrees) in these experiments. The proportion of normal
embryos and survival of eggs until hatching were highest when the eggs were
incubated at 6 °C. During the incubation period, the embryo and yolk
sac size at 280 daydegrees was not significantly different but at 850 daydegrees
the embryo size was inversely related to temperature and the remaining yolk
sac size positively correlated with the incubation temperature. The
transformation of yolk to body mass during incubation appeared to be most
efficient at 4 °C, and the embryos hatched with a larger visible yolk
sac at 6 and 8 °C. The largest larvae (wet-weight) hatched from the
largest eggs and the egg groups incubated at the lowest temperature (4 °C).
There was no effect of temperature on meristic characters. During 6 weeks
post-hatching, all larvae from the three temperature groups were fed
formulated dry feed in excess at 8 °C in low water-level raceway
systems. During startfeeding, the larvae from eggs incubated at the lowest
temperature (4 °C) showed the highest growth rates (SGR). Best
survival of larvae was noted among batches incubated at 6 °C.
(Norwegian College of Fishery Science, University of Tromsų, N-9037
Tromsų, Norway, e-mail of I.B. Falk-Petersen: ingerf@nfh.uit.no)