著者

宮地 傳三郎

出版者

公益社団法人 日本水産学会

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.1, no.6, pp.291-298, 1933-03-18 (Released:2008-02-29)

参考文献数

34

被引用文献数

2 3

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Japanese fresh-water mysids are treated in this paper and their ecology is compared with that of a glacial marine relict Mysis relicta. Japanese relict Mysidacea shall be identified with either of Neomysis awatschensis and N. nigra. Those from Etorohu-Sima of the Kurile Islands, Hokkaidô and the Kwantô Plain belong to the former, and those from the Japan Sea coast of southern Honsyû are refered to the latter. The Neomysis-l ?? kes are all shallower than 22.5m, lying at lower altitude than 10m., within 18km. from the nearest sea. They are accepted as relict lakes, and neither any effect of glacial process nor any active migration of the animal are necessary for Neomysis to reach them, since it is nothing other than the original marine fauna adapted to the change of salinity in them. The Neomysis-lakes of Etorohu-Sima were nearly homothermal at less than 15°C in July-August of 1932. In Tôro-ko, Hokkaidô, the temperature may reach 27.5°C at the surface and was 22°C at all strata in October. In Honsyû, the surface water may rise above 30°C and the bottom water above 20°C in summer. Thus N. awatschensis and N. nigra seem to have a wide temperature range, being contrasted to M. relicta which is a typical stenothermal organism. M. relicta is a steno-oxybiont appearing in Tanytarsus-lakes. If it appears in Chironomus-lakes, it keeps off the hypolimnion with insufficient oxygen to be restricted to the cool well-aerated middle strata. Japanese Neomysis-lakes are all eutrophic plumosus-type, and in. some of them the oxygen in the hypolimnion may become absent in summer. There is no relict lake of Tanytarsus-type in Japan Both N. awatschensis and N. nigra seem as M. relicta to multiplicate in winter season.