Effect of light intensity on growth, survival and skin color of juvenile Chinese longsnout catfish (Leiocassis longirostris Gunther)

Abstract

An 8-week experiment was carried out to investigate the effects of light intensity on growth, survival and skin color of Chinese longsnout catfish juveniles. Five light intensities, 0.15, 0.98, 2.46, 3.82 and 5.28 mu mol.s(-1).m(-2) (5, 74, 198, 312 and 434 lx, respectively), were tested in triplicates. Fish (4.8 +/- 0.01 g) were fed to satiation twice a day (0900, 1600 h). The photoperiod was 12L:12D (0800-2000 h). At the end of the experiment, three fish per tank were sampled to measure skin color by instrumental color analysis. The results showed that growth rate was significantly reduced at lower or higher intensities while light intensity did not affect the survival. The skin color of Chinese longsnout catfish was darkest under 434 lx. It is concluded that light intensity significantly affected growth and optimal light intensity for Chinese longsnout catfish juveniles was about 312 lx. (C) 2005 Elsevier B.V All rights reserved