Oxygen consumption in Oreochromis niloticus (L.) in relation to development, salinity, temperature and time of day |
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Authors: | C D De Silva S Premawansa C N Keembiyahetty |
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Institution: | Department of Zoology, University of Ruhuna, Matara, Sri Lanka |
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Abstract: | Oxygen consumption of Oreochromis niloticus at different stages of development was studied in relation to salinity, temperature and time of day, using a Warburg apparatus. The oxygen consumption of newly hatched (0–14 h) larvae was 3.40 μl O2 larva−1 h−1, of older yolk sac larvae 10.09 μl O2 larva−1 h−1, and of one-month-old fry 32.99 μl O2 larva−1 h−1. The QO2 values showed a decrease with development and growth, ranging from 21.2–26.0 μl O2 mg−1 h−1 in newly hatched larvae to 2.97 μl mg−1 h−1 in one-month-old fry. Changes in oxygen consumption occurred with salinity, the highest being at 17%o. Active larvae (12-24 mm T.L.) showed a doubling of consumption with a 10° C rise in temperature, and their Q10 factor increased from 2.25 to 3.43 with increasing size. Day-old yolk-sac larvae, late yolk-sac larvae (5 days old) and fry of 12 14 mm length all showed a depression in oxygen consumption at midnight followed by a dawn rise. |
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