Effects of photoperiod on survival, growth and feeding of longtooth grouper Epinephelus bruneus larvae
2008
Teruya, K.(National Research Inst. of Aquaculture, Saiki, Oita (Japan)) | Yoseda, K. | Fujii, A. | Kurokawa, Y. | Kawai, S. | Oka, M. | Nishioka, T. | Nakano, S. | Mori, K. | Sugaya, T. | Hamasaki, K.
The larvae of longtooth grouper Epinephelus bruneus were reared in a 150 kL tank until ten days post hatching under a natural photoperiod condition and diurnal rhythms of feeding and tryptic activity of larvae were examined. Further, effects of different photoperiods (24L:0D, 12L:12D, 6L:6D:6L:6D, and 0L:24D) on larval survival, growth and feeding were examined using 500 L tanks until 11 days post hatching. The longtooth grouper larvae fed on rotifers during light periods and tryptic activity was highest at 7 p.m. Larval gut contents were quite few during dark periods and larvae did not grow and survive in tanks with 0L:24D photoperiod. The number of rotifers in larval guts was low in tanks with 24L:0D photoperiod thought larvae fed on rotifers slightly at night. Total length and survival rates of larvae reared in tanks under 24L:0D and 6L:6D:6L:6D conditions showed similar low values, and best growth and survival rates were observed in tanks under 12L:12D condition.
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