著者

西 栄二郎 KUPRIYA-NOVA E. KUPRIYANOVA E.

出版者

横浜国立大学

雑誌

特別研究員奨励費

巻号頁・発行日

2008

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オーストラリア産多毛類と日本産多毛類を中心とする底生生物の生物相を比較しながら、外来種の調査を行った。オーストラリア沿岸の付着生物(カキやイガイなど)の隙間に棲む多くの種類が外来種の可能性があることが確認できた。また、オーストラリア産、日本産、米国西海岸産の数種の比較で、外来種ではなく、それぞれ別個の種である可能性があることがわかった。今後、これらの外来種なのか別個の種なのか判明していない種の起源や移入・伝播経路等をDNA解析により明らかにしていく予定である。また、海洋研究開発機構との共同研究により、深海産の多毛類について新記録種が見つかった。この種はDNA解析により既知種との類縁性が考えられるものの、剛毛などの外部形態に差異があることから新種(未記載種)の可能性がある。今回は採集された個体数が少なく、外部形態の差異が変異なのか固定形質なのか判別できないため、新種または既知種との判断は行っていない。今後の調査により同種が採集された場合には種の位置付けが確定されると思われる。横浜港など東京湾内や相模湾内の底生生物調査とともに、淡水産生物の調査も行った。淡水には特異な進化を遂げた種が分布し、その分布域に外来種が入り込むことで、多くの淡水産種が分布を狭めたり、絶命に瀕する例が知られている。そのため、淡水産の種とそれに影響を及ぼす可能性がある種を調査・研究することを目的とした。欧州の洞窟に棲む種やタイの淡水・汽水に棲むカンザシゴカイ科、日本の洞窟内淡水に生息するホラアナゴカイ科などを調べた。それぞれ現在も良好な分布が確認されたが、今後もモニタリングすることにより、その分布域の減少に注視する必要があると思われる。

著者

西 栄二郎 荒井 寛 笹沼 慎一

出版者

横浜国立大学

雑誌

Actinia : bulletin of the Manazuru Marine Laboratory for Science Education, Faculty of Education and Human Sciences, Yokohama National University

巻号頁・発行日

vol.13, pp.1-12, 2000-03-31

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Chaetopterus gregarius new species (Polychaeta: Chaetopteridae) is described from 120-300m depth off Tokyo Bay, Central Japan. The new species is gregarious and probably epifaunal; masses of irregularly U-shaped, tough, parchment-like tubes were recovered from hard substrata. The species is oculate, of moderate size (up to 57mm long), with 9A+5B+16-23C segments. It appears to differ from other members of the genus in having two kinds of notopodia in region C. When live specimens were placed in fresh water, bioluminescence was seen in the palps and alate (winglike) notopodia of B1, with the most long-lasting and brilliant light at the base of the B1 notopodia. No other areas luminesced. This pattern appears to differ from ones reported from other members of the genus, most of which have been (incorrectly) identified as C. variopedatus.

著者

西 栄二郎 荒井 寛 笹沼 慎一

出版者

横浜国立大学教育人間科学部附属理科教育実習施設

雑誌

Actinia

巻号頁・発行日

no.13, pp.1-12, 2000-03

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Chaetopterus gregarius new species (Polychaeta: Chaetopteridae) is described from 120-300m depth off Tokyo Bay, Central Japan. The new species is gregarious and probably epifaunal; masses of irregularly U-shaped, tough, parchment-like tubes were recovered from hard substrata. The species is oculate, of moderate size (up to 57mm long), with 9A+5B+16-23C segments. It appears to differ from other members of the genus in having two kinds of notopodia in region C. When live specimens were placed in fresh water, bioluminescence was seen in the palps and alate (winglike) notopodia of B1, with the most long-lasting and brilliant light at the base of the B1 notopodia. No other areas luminesced. This pattern appears to differ from ones reported from other members of the genus, most of which have been (incorrectly) identified as C. variopedatus.

著者

岩崎 敬二 木村 妙子 木下 今日子 山口 寿之 西川 輝昭 西 栄二郎 山西 良平 林 育夫 大越 健嗣 小菅 丈治 鈴木 孝男 逸見 泰久 風呂田 利夫 向井 宏

出版者

JAPANESE ASSOCIATION OF BENTHOLOGY

雑誌

日本ベントス学会誌 = Japanese journal of benthology (ISSN:1345112X)

巻号頁・発行日

vol.59, pp.22-44, 2004-07-28

被引用文献数

24 26

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To investigate the invasion history and recent geographic distribution of marine organisms introduced to Japan or transferred domestically to non-native regions, a questionnaire survey on their occurrence in the field, including both published and unpublished records, was conducted in 2002-2003. A total of 105 taxa was reported by 94 respondents. According to three criteria, viz. known or unknown geographic origin, established invasion history, and presumed dispersal mechanisms associated with human activities, 42 taxa were designated as non-indigenous species introduced to Japan through human activities, 26 taxa as indigenous species that are distributed both in Japan and other countries but are introduced from abroad to Japan for fisheries or as fish bait, 20 taxa as cryptogenic species which are not demonstrably native or introduced, two taxa as non-indigenous species that have extended their range to Japan through natural dispersion, and one taxon as an indigenous species. The remaining 14 taxa were considered to have been transferred domestically to new areas. Analysis of the years of first record of 42 non-indigenous species suggests that the rate of invasion has increased over the past century, with seven or eight species being introduced per decade after 1960. Data on temporal change in geographic distribution revealed that many non-indigenous species have become widespread recently, from the Pacific coasts of central Japan to the coasts of the Sea of Japan or northward. However, the species listed in the present study are not exhaustive, and more extensive investigations covering all taxa and all presumed dispersal mechanisms are urgently needed before consideration of legislative management of introduced marine organisms.

著者

西 栄二郎

出版者

横浜国立大学

雑誌

Actinia : bulletin of the Manazuru Marine Laboratory for Science Education, Faculty of Education and Human Sciences, Yokohama National University

巻号頁・発行日

vol.15, pp.1-6, 2003-03-31

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A new species of chaetopterid polychaeta, Spiochaetopterus manazuruensis n. sp., is described from sandy mud shallow bottom of Manazuru, Sagami Bay, Pacific coast of Honshu, Japan. This is the fifth species of Spiochaetopterus to be described from Japan. The species is described and figured and differentiated from other species of the genus with which it might be confused. Based on SEM observations and ones in the literature, the specialized A4 (chaetiger 4 of anterior region) chaeteae are compared with those of other 14 named and unnamed species of Spiochaetopterus. In this feature, in its small size, and in having only 2 middle segments, S. manazuruensis n. sp. appeares to be most similar to northern European S. bergensis Gitay, 1969, but differs from it in the presence of a larger, irregular brown pigmentation on each side extending from the prostomium to the peristomium, and in details of the structure of the A4 modified chaetae.

著者

西 栄二郎 田中 克彦

出版者

公益社団法人日本船舶海洋工学会

雑誌

日本船舶海洋工学会講演会論文集 (ISSN:18806538)

巻号頁・発行日

no.1, pp.415-418, 2005-11