The Israeli Journal of Aquaculture Bamidgeh 56(2), 2004, 102-112.

EFFECTS OF FRESH WATER AND SEA WATER ON GROWTH, ESTRADIOL-17b CONCENTRATION AND
OVARIAN DEVELOPMENT IN JUVENILE TILAPIA


Tulay Altun*, Ercan Sar.han

The Faculty of Fisheries, Cukurova University, 01330 Balcali Adana, Turkey 

 Levent Kayr.n and Figen Doran

Medical Faculty, Cukurova University, 01330 Balcali Adana, Turkey

(Received 14.1.03, Accepted 26.1.04)


Key words: fresh water, Oreochromis niloticus, O. aureus, ovarian development, sea water,
Tilapia zilli



Abstract

The effects of fresh water and sea water on growth, estradiol-17b levels, ovarian and oocyte development of Oreochromis niloticus, O. aureus and Tilapia zilli were determined. Sea water affected growth positively (p<0.05) but estradiol-17b concentrations in fish reared in sea water did not reach the levels in fish reared in fresh water. Ovarian stages developed differently in sea and fresh water. Ovulation occurred only when the fish were grown in fresh water whereas mature and atretic oocytes were seen simultaneously in all species when grown in sea water. There were no statistically significant differences in oocyte diameter between the groups grown in fresh and sea water (p>0.05).

* Corresponding author. Fax: +90-322-3386894, e-mail: taltun@mail.cu.edu.t

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