“Funa” or the crucsian carps,
Carassius carassius (
L.) found in Jo-numa, one of the small lakes of Gumma Prefecture, may be divided into. three populations
* basing on fresh colors and external features.
The fresh one, “Kin” or gold “Funa”, is light reddish orage or yellowish brown in fresh, having ?? slender and wider body. The second one, “Gin” or siler “Funa”, is greenish brown, with a comeplssed body. The third one, “Gengoro Funa”, intrduced from Lake Biwa, is greyish white with a much complessed body.
From the satistical observations we have distinguished somewhat difference in three populations: -in the depth of body (Fig. 1), length of the longest caudal ray (Fig. 2 ), the length of the base of dorsal (Fig. 3), the number of dorsal rays (Fig. 5) and of gill rakers (Fig. 4), excepting with a head length, depth of caudal peduncle, length of middle caudal ray and of the longest pectoral ray.
From the ecological observations there are found some differernce in the sex ratio, growth rate, inhabiting depth and food habit. It is remarkeble that the males of “Ginfuna” are much fewer than the females.
As they spawn approximately in the same season and place, it is provable that they may interbreed freely with each other. A Genetical experiment may be necessary for the problem on the three populations are relatively stable.
From the results of the present studies, the writers concluded that three populations may be considened at least racialy independent respertivey and may not be regarded as a fulctuation or an enviromental difference.
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