INFLUENCE OF BRACKISH WATER ON SURVIVAL
AND GROWTH OF THE JUVENILE WHITE GROUPER,
EPINEPHELUS AENEUS
A. Peduel, B. Ron-2003
The Israeli Journal of Aquaculture –
Bamidgeh, 55(4): 258-264
Abstract:
The natural habitat of the white grouper,
Epinephelus aeneus, is the Mediterranean Sea, which has a salinity of
approximately 35 ppt. As fish species vary in their tolerance of
environmental conditions, potential production in specific conditions must
be determined empirically. The growth, survival and cortisol level of 1.7 g
grouper juveniles grown in diluted sea water (4 ppt) or brackish water (4
ppt) from the Tsofar well in the Arava (southeastern Negev, Israel) was
compared to the growth of similar fish in sea water (43 ppt). Survival in
all treatments was 100%. During the first ten days, the fish grown in
brackish water grew significantly less (p<0.01) than the fish grown in
full-strength or diluted sea water. There were no significant differences
between the treatments during the second growth period or in the final
weight (approximately 9 g). Total cortisol concentrations ranged 2.7-4.5
ng/l and did not significantly differ between treatments. Results indicate
that the white grouper can flourish in water with salinity as low as 4 ppt
and that there are no detrimental chemical factors in the brackish water
from the Tsofar well.
(Israel
Oceanographic and Limnological Research, The National Center for
Mariculture, P.O. Box 1212, Eilat, 88112, Israel, Fax: +972-8-6375761, e-mail: ronbenny@agri.huji.ac.il)