キスの自然産卵について

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[Author abstract]The sand borer, Sillago sihama (FORSKAL), is an important demersal fish for both the commercial catch and the sport fishing. Since the resources of the fish have been recently decreasing by means of the reclamation work of coast and the water pollution, it is necessary to propagate the fish artificially. Sato et al. and Kiyono et al. reported on the artificial fertilization and the breeding of the sand borer, its parent fish were spawned by mainly hormone treatments. Our examinations, however, were made by using the eggs which were obtained from natural spawning fish. The present paper reports the resalt of some approaches on the natural spawning of the sand borer. On June 2, 1975, one female and three male adult fishes, caught by hooking in Uragami Bay, Wakayama Pref., were placed in a 0.5 t plastic water tank and were bred during the spawning period. The results of investigation on the natural spawning were as follows: 1) One female fish of 201 mm in fork length spawned 65 times repeatedly during 108 days from June 17 to October 2. 2) The highest and lowest egg numbers per one spawning were 59,600 and 1,100, respectively, and the total ones amounted to 1,800,750. 3) The water temperatures during the spawning period were ranged from 21.0℃ to 30.5℃, but the optimum temperature for spawning appeared to be restricted from 26.0℃ to 29.0℃. 4) It was supposed that the optimum spawning time was centered between about P.M. 6 and 7 O'clock, and somewhat corresponding to the sunset time, followed by before and behind that time. 5) The egg diameter varied from 0.621 to 0.782 mm, with the average of 0.686 mm. 6) The spawning eggs were concluded to be in the good condition, because the fertilized eggs indicated the normal hatching rate.[著者抄録]1975年6月2日､和歌山県東牟婁郡那智勝浦町浦神湾において釣獲したキス親魚雌1尾雄3尾をパンライト水槽に収容､飼育し､自然産卵をおこない､次の結果を得た｡(1)1尾の雌 (尾叉体長20.1cm)が6月1日より10月2日までの108日間に65回の産卵をくりかえした。(2)産卵数は1回に最高､59,600粒､最低1,100粒で､合計1,800,750粒の卵を産出した。(3)産卵期間中の水温は21.0～30.5℃であったが産卵最適水温は26.0～29.0℃と推定される。(4)産卵時刻は日没頃(18～19時)を中心とし､その前後にわたると推察される。(5)卵径は､0.621～0.782mmで平均0.686mmであった。(6)本実験で産出された卵は正常ふ化率の実験から良質卵であると判断された。
近畿大学の論文
1977-03-15

キスの自然産卵について

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