脊椎骨数によるスケトウダラ地方群の分離〔英文〕

概要

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Geographical variation in mean counts of vertebrae of the walleye pollock were statistically analyzed in relation to its distribution in the regions of the Sea of Japan, the Okhotsk Sea and the Pacific Ocean adjacent to Hokkaido, the northern island of Japan. The frequency distribution of the numbers of vertebrae is normal in an area. Significance tests indicated that there may have been eight local forms with distinctive means in the investigated regions. The means of all samples were concentrated on four clumps in Cartesian co-ordinates crossing at an angle of 60° between co-ordinates of abdominal and caudal vertebrae. Mean vertebral counts increased with an increase in latitude. These results indicate that there are at least eight local forms in the sea regions surrounding Hokkaido, but it is also possible that some local forms migrate to other habitats from their spawning ground after their period of reproduction. The term "local form" is a reasonable proposition for geographical variations instead of "population" when the phenotypic characteristics are used for classification.
日本水産學會の論文