著者

平嶋 健太郎 立原 一憲

出版者

The Ichthyological Society of Japan

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

vol.47, no.1, pp.29-41, 2000-05-25 (Released:2010-06-28)

参考文献数

28

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Members of the genus Rhinogobius are widely distributed in Far East Asia, at least 11 species having been recognized in Japan. Of the six species recorded from Okinawa Island, two are land-locked (“aobara-yoshinobori” R. sp.BB and “kibara-yoshinobori” R. sp.YB) and the remainder amphidromous. Embryonic development and morphological changes in the two land-locked species are described from artifically-reared eggs, larvae and juveniles. Survival and growth of the two species were compared under different salinities (0-35%0) dur-ing a 21-day period following hatching. Although egg diameters of both species were almost the same (“aobara-yoshinobori”; 4.3±0.1 mm, “kibara-yoshinobori”; 4.3±0.2 mm), newly-hatched larval morphology, and larval and juvenile salinity tolerance clearly differed. Newly-hatched larvae of “aobara-yoshinobori” had a flexed notochord and caudal fin rays already developed. The yolk was completely consumed 3 days after hatching. By comparison, “kibara-yoshinobori” hatched at an ealier developmental stage, having a straight notochord. The yolk disappeared 7 days after hatching. Larvae and juveniles of “aobara-yoshinobori” were less toler-ant in high salinity than those of “kibara-yoshinobori”. The results suggested that the two land-locked gobies have become adapted to a wholly fluvial life cycle, through somewhat different strategies.

著者

岩槻 幸雄 関 伸吾 山本 彰徳 森澤 友博 稲野 俊直 斉藤 裕也 平嶋 健太郎

出版者

鹿児島県自然環境保全協会

雑誌

Nature of Kagoshima = カゴシマネイチャー : an annual magazine for naturalists (ISSN:18827551)

巻号頁・発行日

vol.46, pp.467-480, 2020

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Habitat and actual records of charr, Salvelinus leucomaenis, from Wakayama Prefecture were investigated by hearing survey and their reliable information. Hearing survey in Wakayama Prefecture suggested their habitat including both probable native and introduced individuals from most of Wakayama rivers, the Kinokawa (including the Kishikawa River), the Aridagawa, the Hidakagawa, the Hikigawa, the Kozagawa and the Kumagawa Rivers in Wakayama although the charr population (Kirikuchi charr) of the Hidakagawa River was considered as extinct in around 1960 of flood disaster by Kubo and Kimura in 1998. Subsequently, native Kirikuchi charr and hybrids between native Kirikuchi charr in Nara and the charr of the Ibigawa River population, Gifu were introduced into upper stream of Komoridani valley, the Hidaka River several times in early 1980. Probable and reliable information of native populations of Wakayama charr were reconfirmed from the Aridagawa and the Hikigawa Rivers and actual specimens of the charr were confirmed from the Aridagawa, the Hidakagawa, and the Hikigawa Rivers. Photographic reconfirmation of the charr was done in middle basin of the Kumanogawa River in Wakayama, too. Further detailed genetic analysis of their Wakayama charr populations would make evidence of native or introduced populations in future. Whitespots' condition on dorsal part of the body in true Kirikuchi charr in the inhibited river zones for the charr catch in the Yumitehara river, the Kawasako River were noted, being variable in presence or absence of dorsal part of the body in true Kirikuchi charr although it has been considered as generally having no whitespotted body of the true Kirikuchi charr before.

著者

平嶋 健太郎 中村 和矢

出版者

日本魚學振興會

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

vol.61, no.2, pp.53-57, 2014

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シマヒレヨシノボリRhinogobius sp. BFは,鈴木ほか(2010)によって近年認められたヨシノボリ属魚類である。しかし,これまで他のヨシノボリ類と混同されていたこと(明仁ほか,2013)や認識されて間もないことから基礎的な資料は少ない。本種の分布域は,瀬戸内海東岸を中心とした地域である。これは,シマヨシノボリR. nagouaeやカワヨシノボリR. flumineusなど同属のヨシノボリ類の分布域と比較して狭く(明仁ほか,2013),また,その生息環境は平野部の野池や河川下流域,わんどなどであり(鈴木・向井,2010; 平嶋,2011),人為による環境改変の影響を受けやすいと考えられる。加えて,環境省レッドリストで準絶滅危惧(環境省,2013),和歌山県版レッドデータブックで学術重要(中谷ほか,2012),愛媛県版レッドデータブックで地域個体群に指定(高橋,2003)されていることから,本種の生息地の保全が望まれる。その一方で,本種が他地域へもち込まれた場合に他種との交雑(向井ほか,2012)や競合など大きな撹乱の元となることが危惧される(鈴木ほか,2010; 鈴木・向井,2010)。また,本種個体群の分散や交流に大きく影響する仔稚魚期の生活史に関して,Tsunagawa et al. (2010)は耳石のSr/Ca比により本種が河川陸封性であることを明らかにしているが,仔稚魚が実際に沿岸や海域で生残可能かどうかは明らかでない。