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oai:fra.repo.nii.ac.jp:02001652 2025-12-11T00:50:50Z 12:14:1716950587014

根室湾から採集された上部浅海系の貝類の特性 Characteristics of upper-sublittoral Molluscs of Nemuro-Bay, Eastern Hokkaido Japan, Collected by the R/V Tansei-Maru 土田, 英治 ツチダ, エイジ Tsuchida, Eiji 土田 ツチダ Tsuchida 英治 エイジ Eiji metadata only access The molluscan fauna in Nemuro Bay, eastern Hokkaido was surveyed by dredging at depths of 9 to 27m during a cruise of R/V Tansei-Maru in September 1995. As a result, 3345 individuals of 36 species (10 gastropods, 1 scaphopod, and 25 bivalves) were collected. Based on the collected material, the following aspects were revealed concerning the distribution of molluscs in the bay. 1) All species collected in this survey were described and illustrated. This will be basic information on molluscan fauna in eastern Hokkaido which has not been well investigated. 2) In 13 common species of bivalves, the shell length of all collected specimens was measured, and the frequency of size distribution was plotted. The results clearly showed that immature individuals are considerably predominant over adults in these species. This may include the artifact in sampling, but probably represents high rate of survival of juveniles. 3) Details of fauna among stations are characterized as follows: (i) The species composition in stn. 1 differs from that in other stations in containing Glycymeris yessoensis, Falaniella usta, Spisula (Mactromeris) polynyma, Callista (Ezocalliata) brevisiphonata, Nuttalia ezonis, and Ruditapes philippinarum. These bivalves are characteristic of sandy bottom with high rate of water exchange. (ii) Stns. 7 and 9 seem environmentally similar, but Patinopecten yessoensis was found only in the latter station. (iii) Stn. 2 in the central part of the bay is environmentally stable, and the bottom is muddy. A great number of juveniles of Patinopecten yessoensis and other bivalves were found in this station. (vi) Shells of Patinopecten yessoensis were covered with Crepidula grandis and ascidians in stn. 9, but in contrast, were free from these animals in stn. 7. (v) Predatory gastropods such as Euspira pipla, Ceratostoma (Ocenebra) japonicum and Philine argentata are distributed throughout the bay regadless of bottom sediment. 4) Members of collected molluscs (34 identified species out of 36 collected species) can be categorized into five biogeographical elements: (i) temperate species ranging from southern Hokkaido to Kyushu, (ii) roughly cool temperate-subarctic species occurring mainly in Hokkaido and Tohoku, but also extended to more southern area including Seto Inland Sea, (iii) strictly cool temperate-subarctic species distributed north to Boso Peninsula or Kashima-nada, (iv) narrowly distributed subarctic species restricted to cold water area of Tohoku and Hokkaido, and (v) widely distributed subarctic species occurring in Hokkaido, Kuril Islands, Aleutian Islands and Alaska. In summary, the fauna of the bay mostly consists of subarctic species, excluding 8 temperate species; no warm temperate species are included. 北海道区水産研究所 Hokkaido National Fisheries Research Institute 1998-07 jpn departmental bulletin paper https://fra.repo.nii.ac.jp/records/2001652 hnf_k_62_83 https://agriknowledge.affrc.go.jp/RN/2010572827 日本農学文献記事索引(agriknowledge) AN1015410X 0513-2541 北海道区水産研究所研究報告 Bulletin of the Hokkaido National Fisheries Research Institute 62 23 83 105