Study on the variavility of life-history and the genetic variation in the Japanese freshwater sculpins

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It was examined there was a correlation between the variavility of life-histories and the intrapopulational genetic variation in five species of Japanese freshwater sculpins, Cottus amblystomopsis, C.nozawae, the small-egged C.pollux, the large-egged C.pollux and C.reinii, which have different life-cycles from each other. The main results obtained in the present study are as follows :1) The egg diameter ranged from 1.6 to 2.1 mm and from 1.8 to 3.1 mm, and the body size of just hatched larvae varied from 6.4 to 7.4 mm and from 8.5 to 9.5 mm in amphidromous C.amblystomopsis and the small-egged C.pollux, respectively.2) In a lacustrine land-locked species C.reinii, the egg diameter ranged from 1.4 to 1.6 mm and the body size of just hatched larvae varied from 4.9 to 5.3 mm.3) In the fluvial species C.nozawae and the large-egged C.pollux, the egg diameter was 2.5 to 3.1 mm and 2.5 to 3.7 mm, and the body size of varvae was 7.6 to 8.0 mm and 8.5 to 9.5 mm, respectively.4) From the results mentioned above, it was concluded that there was no correlation between the differences of life-cycles among five species and the variavility of life-history characters such as egg size and larval size.5) Compared between the intrapopulational genetic variation of five Cottus species and the variavility of life-history characters in each species, it might be no reasonable to consider that there is a correlation between the variavility of life-histories and the genetic variavility in Cottus species.