著者

一丸 俊雄 水田 浩二 中園 明信 TOSHIO ICHIMARU KOJI MIZUTA AKINOBU NAKAZONO 長崎県総合水産試験場 長崎県総合水産試験場:(現)長崎県五島支庁水産課 九州大学大学院農学研究院 Nagasaki Prefectural Institute of Fisheries Nagasaki Prefectural Institute of Fisheries:Fisheries Division of Goto Branch Office of Nagasaki Prefectural Government Faculty of Agriculture Kyushu University

出版者

日本水産學會

雑誌

日本水産学会誌 = Bulletin of the Japanese Society of Scientific Fisheries (ISSN:00215392)

巻号頁・発行日

vol.72, no.1, pp.21-26, 2006-01-15

参考文献数

11

被引用文献数

7

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1998~2004年の4~8月に長崎県五島列島沖および鹿児島県屋久島沖で採集したホソアオトビHirundichthys oxycephalusの卵を顕微鏡下で観察した。本種の卵は片側に直径20μmの纏絡糸が1本と10μmの纏絡糸が5~7本,その反対側に6μmの纏絡糸を9~14本有しており,H. coromandelensisの卵に似た形状をしている。纏絡糸の径はH. coromandelensisよりホソアオトビの方が細く,これによって2種を区別することが可能と考えられた。卵の出現は鹿児島県では5~7月,長崎県では7~8月であり,水温により産卵期は異なるものと考えられた。Eggs of the mirror-finned flying fish Hirundichthys oxycephalus were collected from the drifts near Goto Islands and Yaku Island, from April to August within the years of 1998 to 2004. To identify species, the eggs were reared and the hatched larvae were observed. The eggs were 1.6-2.0mm in diameter. Three types of filaments were recognized. One was a single filament of 20μm, the others were 5-7 filaments of 10μm, and 9-14 filaments of 6μm. The number of filaments observed in H. oxycephalus was similar to that formerly reported in H. coromandelensis, however, the thinner diameter of H. oxycephalus filaments than that of H. coromandelensis makes it possible to distinguish between the two species. The eggs were collected in Kagoshima from May to July, and in Nagasaki from July to August, and this difference seems to be due to the difference of water temperature between the two localities.

著者

一丸 俊雄 中園 明信 Toshio Ichimaru Akinobu Nakazono 長崎県総合水産試験場 九州大学農学部水産学科 Nagasaki Prefectural Institute of Fisheries Faculty of Agriculture Kyusyu University

出版者

The Japanese Society of Fisheries Science

雑誌

日本水産学会誌 = Bulletin of the Japanese Society of Scientific Fisheries (ISSN:00215392)

巻号頁・発行日

vol.65, no.4, pp.680-688, 1999-07-15

参考文献数

10

被引用文献数

1 1

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ツクシトビウオの成熟と産卵の実態を明らかにする目的で, 定置網, まき網, 船曳網の漁獲物について性比, GSI, 卵径の測定, 卵巣の組織観察等を行った。岸側の漁獲物では漁期初めに雌の割合が低く, その割合は徐々に高まった。沖側では漁期を通じて約80%が雌であった。GSIは岸側で低く, 沖側で高かった。卵巣内には今後排卵されると思われる卵群の他に発達するであろうと考えられる卵群の分離が見られた。また, 最大の卵径は岸で小さく, 沖で大きい傾向を示し, 岸側の卵巣では97%の高い比率で排卵後濾胞が認められた。ツクシトビウオは産卵期に雌雄別群として来遊し, 最初雄が接岸し, 後から成熟した雌が接岸して産卵が行わると考えられ, 1産卵期中に複数回産卵を行っていると推察された。Investigations were carried out by using the samples caught with set nets, seine nets, and boat seines from 1992 to 1996. Most of the catches with set nets, operated in the near shore, were male in the early fishing season, and according with passage of fishing season the female ratio increased gradually. Eighty percent of the catches with seine nets, operated in the offshore, were female. GSI of females was higher in the catches of the offshore than the near shore. The frequencies of the oocyte diameter showed that ovaries have a small and middle sized oocyte group, and large sized maturing oocyte groups. Ovaries of the offshore catches have large sized oocytes, and ovaries of the near shore catches have small and middle sized oocytes or the transparent oocytes remaining unspwned at the latest spawning. Ninty seven percent of the female catches in the near shore have postovulatory folicles in the ovaries. These results show that the male and female come to the north west coastal waters of Kyusyu in spawning season as separate groups : the male is in the near shore, the female is in the offshore. When ripened, the female go to the near shore for spawning, and immediately after spawning come back to the offshore. The spawning times of C. heterurus doederleini are thought to be at least twice during a spawning season.