Egg and larval quality
criteria as predictive measures for juvenile production in turbot (Scophthalmus
maximus L.)
E. Kjørsvik, K. Hoehne-Reitan, K.I. Reitan
Aquaculture, 227(1-4): 9-20
Abstract:
Although much effort has been made to evaluate
criteria for marine egg and larval quality, the significance of poor egg
quality for the results in the final juvenile production has not been
clarified. The aim of our experiments with turbot (Scophthalmus maximus)
was to determine whether the initially observed egg quality affected
offspring viability and normal development up to the juvenile stage.
Eggs from each of six individual females were divided
into three replicate groups, and the eggs in each replicate was quality
evaluated according to fertilization rates and the ratio of normal cell
cleavages (blastomere morphology) at the 8–32 cell stage. The condition of
yolk-sac larvae was tested by an acute high salinity stress test, and the
larvae were fed according to our standard feeding regime with microalgae,
enriched rotifers and Artemia nauplii.
Significant positive correlations were found between
observed egg quality characteristics and hatching rates, larval tolerance to
acute stress, and to survival, metamorphosis and juvenile pigmentation.
Larvae hatching from poor quality egg groups thus had a lower viability and
were less able to develop normally to the juvenile stage than larvae from
good quality egg groups. Our conclusion is that egg quality observed as
fertilization rate and rates of normal blastomeres at early egg stages may
be a useful predictive tool for evaluation of the potential juvenile
production in turbot.
(Department of Biology, Brattøra Research Centre,
Norwegian University of Science and Technology, N-7491, Trondheim, Norway,
e-mail: Elin.Kjorsvik@bio.ntnu.no)