the effects of different
levels of salinity on egg hatching and larval survival of silver pomfret (pampus
argenteus).
K. Al-Abdul-Elah, Salim El-Dakour, T. Dashti, S.
Almatar
Abstract:
Different salinities were tested to determine the
best egg hatching rate (experiment 1) and larval surivival and condition
(experiment 2) of silver pomfret (Pampus argenteus). The tested salinities
for both experiments were 5, 10, 20, 30 and 40 ppt. In experiment1, twenty
2-liter aerated glass beakers were stocked with 200 egg/beaker. Water
temperature, dissolved oxygen and pH were 29.1-29.8 °C, 6.2-7.4 mg/l and
8.14-8.56, respectively. The hatched larvae were counted 17 hours after
stocking. In experiment 2, similar experimental parameters were applied and
no live food was supplied. The dead larvae were counted and removed daily
until day 7. Results of the first experiment showed that hatching rate
(27.3%) at salinity 40 ppt was significantly higher (P<0.05) than the
other treatments (0-5%). Although survival of larvae at the age of 48 hours
post-hatching was statistically similar at 10, 20 and 30 ppt, their general
condition was only acceptable at 20 and 30 ppt. Thus, in the second
experiment the best larval survival (91.6% and 80.8%) and condition at the
age of 48 hours were obtained at salinities 20 and 30 ppt (P<0.05).
Consequently, the optimum salinity for hatching silver pomfret is 40 ppt but
the best salinities for larval rearing at the initial feeding stage (48
hours) are 20 and 30 ppt.
(Kuwait Institute for Scientific Research, Food
Resources Division, Mariculture and Fisheries Department, P.O. Box 1638,
22017 Salmiya, Kuwait)