Resting metabolism and heat increment of feeding in mandarin fish (Siniperca chuatsi) and Chinese snakehead (Channa argus)

Resting metabolism was measured in immature mandarin fish Siniperca chuatsi weighing 42.1-510.2 g and Chinese snakehead Channa argus weighing 41.5-510 .3 g at 10, 15, 20, 25, 30 and 35 degreesC. Heat increment of feeding was m easured in mandarin fish weighing 202.0 (+/-14.0) g and snakehead weighing 200.8 (+/-19.3) g fed swamp leach Misgurnus anguillicaudatus at 1% body wei ght per day at 28 degreesC. In both species, weight exponent in the power r elationship between resting metabolism and body weight was not affected by temperature. The relationship between resting metabolism and temperature co uld be described by a power function. The temperature exponent was 1.39 in mandarin fish and 2.10 in snakehead (P < 0.05), indicating that resting met abolism in snakehead increased with temperature at a faster rate than in ma ndarin fish. Multiple regression models were used to describe the effects o f body weight (W, g) and temperature (T, <degrees>C) on the resting metabol ism (R-s, mg O-2/h): In R-s = - 5.343 + 0.772 In W + 1.387 In T for the man darin fish and In R-s = -7.863 + 0.801 ln W + 2.104 In T for the Chinese sn akehead. The proportion of food energy channelled to heat increment was 8.7 % in mandarin fish and 6.8% in snakehead. (C) 2000 Elsevier Science Inc. Al l rights reserved.