Tank wall colour and light level affect growth and survival of Eurasian perch larvae (Perca fluviatilis L.)

The influence of interaction between light intensity and tank wall colours on survival and growth of perch larvae (Perca fluviatilis L.) was investigated for 15 days after hatching. Three light intensities (250, 400 and 800 Ix) and four wall colours (black, dark grey, light grey and white) were used. At the end of the experiment, survival rates ranged between 1% and 26%, and varied according to the different treatments (P = 0.0001; df = 11). A global effect of light intensity was detected(P = 0.0001; df = 2) and the highest survival rate was observed under 250 Ix. Survival was also influenced by the tank wall colour(P = 0.0001; df = 3): light grey showed the best result (17%). The greatest growth in weight and length was observed in tanks with light grey and white walls, which were strongly illuminated, while the lowest growth was recorded in the tank with black walls and 250 lx illumination. (C) 2000 Elsevier Science B.V. All rights reserved.