can physiological and
metabolic status of hatching atlantic wolFfish (Anarhichas lupus) predict
survival and growth rate of juveniles?
S.
Lamarre, N. Le François, I.B. Falk Petersen, P. Blier
Abstract :
Varying egg quality is one of the limiting factors
for successful mass production of fish juveniles as it may influence the
survival, growth rate and development of fish. Growth rate is one of the
most important factors in aquaculture and only a few studies focus on the
effects of egg quality on growth rate and survival. This work aims to
compare growth rate and physiological characteristics (digestive and
metabolic enzyme activities) of Atlantic wolffish larvae hatching from egg
masses of different quality. Eggs were collected from the wild in 1999 and
2000, years representing good and poor environmental conditions,
respectively. There was no mortality after hatching in the first year in
contrast with 34% in the latter. Since the experimental conditions were the
same for the two years, explanation for different survival may reside in the
respective egg quality. Growth rates of larvae were significantly different
between the two years. There were also significant differences between
pyruvate kinase and trypsin activities at hatching; differences which
remained after 60 days. This suggests that food assimilation may be a
function of larval condition and that PK and trypsin activity could be used
as predictors of survival and growth rate of juvenile wolffish.
(Département
de biologie, Université du Québec à Rimouski, Rimouski, QC G5L 3A1,
Canada)