Ali Muhammad Mastoi, Mithun Sukumaran, Anila Mastoi*, Anuar Hassan and Anil Chatterji

Institute of Tropical Aquaculture, University Malaysia Terengganu, 21030, Kuala Terengganu (Malaysia) (*Department of Soil Science, Sindh Agriculture University Tando Jam, Pakistan)


During the acclimatization of the fingerlings of red tilapia (Oreochromis mossambicus  Oreochromis niloticus) and in the control groups of these fishes, no mortality was observed whereas within 15 hours of the experimental period for infected groups, all fingerlings were found dead. The oxygen consumption was more or less uniform in control groups indicating the most comfortable conditions for the fingerlings. During 4 to 6 hours of the experiment, the highest values of oxygen consumption (0.140-0.145 mg/ml) were recorded in the control group (P>0.05; r=0.412). On the contrary the rate of oxygen consumption was the maximum in control group during 8-10 hours (10.7%) followed by 2- 4 hours (7.4%) during the experimental period. A maximum oxygen consumption of 0.320 mg-1ml-1h-2 was observed at 12 hours of the experiment where infected fishes showed maximum stress condition. The oxygen consumption was the lowest at 2 hours (0.160 mg-1ml-1h-2) when the infection in fishes was minimum (<0.05; r=0.99). A gradual increase in the rate of oxygen consumption was observed during 6-8 hours (20%) and minimum (8.5%) during 2-4 hours (P<0.05; r=0.98).

Key words : Oreochromis mossambicus, Oreochromis niloticus. Red tilapia, YSI probe.

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