著者

北川 哲郎 森下 匠 細谷 和海

出版者

近畿大学農学部

雑誌

近畿大学農学部紀要 = Memoirs of the Faculty of Agriculture of Kinki University (ISSN:04538889)

巻号頁・発行日

no.45, pp.129-134, 2012-03 (Released:2013-10-08)

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チョウセンブナMacropodus ocellatusの繁殖生態について,屋外および飼育室における飼育試験によって調査した。産卵は,屋外,飼育室内のいずれにおいても,雌に対して雄1尾を投入した飼育容器内のみで観察された。雌は同一容器に複数尾を投入しても問題なく産卵に至った。確認された産卵数は,78-324粒であった。産卵周期を観察するため,飼育室内で産卵した雌雄の2組を飼育し続けたが,産卵後の雄は雌を激しく攻撃し,再び産卵行動をとることはなかった。受精卵は産卵後約2日で孵化し,孵化後6日目で摂餌を開始した。孵化直後の仔魚は強い浮力を有し,浮遊物の付近や飼育容器の壁面沿いに塊をなして浮遊していた。孵化直後の遊泳力は皆無であり,能動的な遊泳が観察されたのは孵化後5日目であった。

著者

北川 哲郎 小田 優花 細谷 和海

出版者

近畿大学農学部

雑誌

近畿大学農学部紀要 = Memoirs of the Faculty of Agriculture of Kinki University (ISSN:04538889)

巻号頁・発行日

vol.46, pp.31-36, 2013-03-01

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[Synopsis] The paradise fish, Macropodus opercularis is distributed from the northern part of Vietnam to the Ryukyu Archipelago, and categorized as an endangered species in Japan. The endemism of the Okinawan population was not proven, even though Okinawa is isolated from the mainland of East and Southeast Asia. Furthermore, the ecological information was not fully investigated and the quantities are not sufficient enough to protect it. To elucidate the local variation in paradise fish, reproductive characteristics of the Okinawan fish population were examined in the laboratory. During the trials, a pair of broodstock were reared under constant environments (25 ± 0.5 °C , 14 h L - 10 h D). Each reproductive behavior was observed once per four to ten days at least. The number of the fertilized eggs was counted as being 319 - 581. Hatching was observed two days later, and then the larvae proceeded to feed six days after hatching. The newly hatched larvae drifted beneath the water surface, or fell down on the bottom of the tank. The fertilized eggs were large, and buoyancy was tenuous, if compared with the case of typical M opercularis from the mainland China. The egg-mass after spawning and prelarvae under a bubble nest were guarded by a single male parent. Protective behavior was also found in females. However, female was often attacked by the male if they were mistakenly perceived as enemy by himself. In this experiment, the filial cannibalism was not observed as far as each broodstock is concerned.

著者

北川 哲郎

出版者

近畿大学農学部

雑誌

近畿大学農学部紀要 = MEMOIRS OF THE FACULTY OF AGRICULTURE OF KINKI UNIVERSITY (ISSN:21896267)

巻号頁・発行日

no.49, pp.1-25, 2016-03-31

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〈Synopsis〉In captive environment, reproductive characteristics of seven bitterlings (Tanakia lanceolata, T. limbata, Acheilognathus rhombeus, A. cyanostigma, A. melanogaster, A. tabira jordani, and A. t. tabira) were estimated by the breeding experiments with Schale's method. Major interspecific difference were confirmed on the spawning pattern and survival rates to emergence from hatching. Some different initial growth patterns were observed in some closely-related Acheilognathus spawning in spring. Such abnormalities as deformation of yolk sac or vertebrae were observed. The achievements would be contributed to ex situ preservation as well as in situ conservation and even taxonomical studies.