Changes in proximate composition and estimates of energetic costs during upstream migration and spawning in Atlantic salmon Salmo salar

摘要: 1. There were marked changes in the relative lipid content of somatic and visceral tissues during course upstream migration spawning. The per 100 g wet tissue mass was high maturing salmon July (soma, pooled sexes: 12.1 g; viscera: 11.4g males 7.3 females) decreased to a minimum after spawning November (soma: 2.1 1.6 g). Percentages protein soma viscera relatively stable study period, ranging from 21.9 (soma) 16.3 (viscera) -1 fish September-October, 17.1 16-1 spent salmon. carbohydrate small, between 0.27 2.4 mass. 2. Application energetic coefficients suggested that energy 814 kJ (pooled sexes) caught coastal waters July, 370 river November. Visceral density same 706 570 females 340 360 kJ, respectively. 3. Mean gonadosomatic index (GSI) values, terms males, just prior 0.4 3.2, corresponding figures for 2.8 28.6. 4. Gonadal contents unit estimated be higher than except fish. Prior 845 gonad 375 males. After gonadal 280 385 mass, 5. energy, somatic, highly correlated with percentage water. 6. Total loss due 60% 70% body reserves migration. It similar females, but large small Estimated investment reproduction significantly survival rates 12 Norwegian populations Atlantic