Pre-feeding larvae (Cromileptes
altivelis) study (done by the Gondol Research Institute for Marine
Culture or GRIMC)
The primary problem in grouper culture was high mortality
in initial stage of larvae. Some experiments on larval rearing of grouper
Cromileptes altivelis had been carried out to solve those problems. Results
of those experiments showed that mortality of larvae is much higher in
initial stage up to day 4-9. The main factors that determine larvae
mortality are biotic factors (e.g., food, disease, parasitism and predation)
and abiotic factors (e.g., oxygen content, pH. salinity, toxic substances,
and temperature).
Previous studies have reported that adding oil of 0.3
ml/m² on water surface of larval rearing tank significantly reduce the
mortality of humpback grouper larvae. This oil addition was needed from D1
to D9 old larvae. Another experiment on water exchange suggested that
early stage of larvae (day 0-10) is sensitive to fluctuation of environmental
factors. Highest survival rate was found on treatment without water
exchange during the 10 days larval rearing. Further, some experiments have
been done to get more information on environmental factors, both during the
embryonic development and larval rearing of grouper.
(from Grouper Research Briefs in Aquaculture Asia,
Vol. VI, No. 2, April-June 2001)