The rate of production and food consumption of the biwamasu oncorhynchus rhodurus population in lake biwa japan
Miura, T.; Suzuki, N.; Nagoshi, M.; Yamamura, K.N.
Researches on Population Ecology 17(2): 135-154
ISSN/ISBN: 0034-5466 Accession: 006746374
The rate of production of the biwamasu, O. rhodurus, population in Lake Biwa [Japan] in 1969-1971 and the amount of food consumption necessary to sustain the rate of production were estimated. The total annual population production calculated on a monthly basis was 112.3 .times. 106 kcal in 1969-1970 and 130.9 .times. 106 kcal in 1970-1971. During the 1st 2 yr of life the rate of production markedly exceeded the rate of mortality. During the successive 3 yr of life in which the salmon were exposed to the fishery was production less than mortality. The total annual food consumption was 870 .times. 106 kcal in 1969-1970 and 949 .times. 106 kcal in 1970-1971. The gross growth coefficient (K1) in terms of energy was unexpectedly low (approximately 13-14%). Characteristics of production of the salmon population are discussed in comparison with those of several fish species including carnivorous and herbivorous as well as piscivorous fishes.