EFFECTS OF TEMPERATURE ON THE GROWTH OF JAPANESE FLOUNDER

Rearing experiments were carried out to examine the effects of tempera ture on the growth of Japanese flounder Paralichthys olivaceus at 10, 15, 20, 25, and 30-degrees-C with fish of about 4, 16, 88, and 176 g i nitial body weight. Fish were fed to satiation twice a day with a comm ercial pelleted diet for 20 days. In all body weight groups, the daily growth rates increased with temperature up to 20 or 25-degrees-C, tho ugh there was little difference in the rates between these temperature s. However, the rates decreased at 30-degrees-C. The daily feeding rat es also increased with temperature up to 25-degrees-C, while the feed conversion efficiency decreased above 20-degrees-C. Therefore, the opt imum temperature for the growth of Japanese flounder of the sizes test ed is probably between 20 and 25-degrees-C. The daily growth rate at 3 0-degrees-C decreased more in larger flounder (88 and 176 g) than in s maller ones (4 and 16 g), and the higher catabolic rate at 30-degrees- C for larger flounder appeared in the relationship between feeding rat e and growth rate. Therefore, the high energy expenditure for cataboli sm appears to reduce the energy available for growth of larger flounde r at 30-degrees-C.