FEED-INTAKE, GROWTH-RATE AND BODY-COMPOSITION OF JUVENILE BALTIC SALMON EXPOSED TO DIFFERENT CONSTANT TEMPERATURES

Feed intake, specific growth rate and changes in body composition of a ge 1+ and 2+ Baltic salmon, Salmo salar L, were studied for fish held under constant temperature conditions. The 1+ fish (60 g) were reared for 6 weeks at 11, 15, 17, 19 or 23 degrees C and 2+ fish (250 g) were held at 15 degrees C. Feed intake of 1+ salmon increased from 176 kJ kg(-1) day(-1) at 11 degrees C to 275 kJ kg(-1) day-1 at 17 degrees C and decreased to 229 kJ kg(-1) day(-1) at 23 degrees C. Specific growt h rate increased from 1.18% day(-1) at 11 degrees C to 1.59% day(-1) a t 15 degrees C and decreased to 0.56% day(-1) at 23 degrees C. Optimum temperatures for feed intake and growth were estimated at 17.8 degree s C and 15.6 degrees C, respectively, and estimated upper thermal limi ts for feeding and growth were 29.0 degrees C and 24.1 degrees C, resp ectively. Models for feed intake and growth rate in relation to temper ature and fish size are presented. The utilization efficiency of inges ted energy decreased from 57% at 11 degrees C to 22% at 23 degrees C. For all groups of if fish, most (approximately 86%) of the weight gain consisted of water. Lipid deposition accounted for about 52% of the b ody energy gain irrespective of rearing temperature.