ハガツオの人工ふ化と仔稚魚の飼育

概要

論文の詳細を見る
[Author abstract]Hitherto no successful study has been reported on the artificial fertilization and rearing of larvae in bonito, Sarda orientalis (TEMMINCK et SCHLEGEL). The authors made some trials of artificial fertilization of this fish aboard some professional fishing vessels during spawning season of the fish (May～June). The mature fish were caught on May 15 and June 10 by a trap net near the coast of Oshima Island near Shionomisaki. Ripe eggs were obtained from the fish and about 10 thousand eggs were fertilized. Each egg has several oil granules. The fertilized eggs are buoyant, spherical and 1.32 to 1.45 mm in diameter. The fertilized eggs were then transported from Oshima to the Shirahama Fisheries Laboratory of the Kinki University, Wakayama Prefecture, and kept there in cylindrical tanks of 0.03 to 3 tons. The eggs hatched out in about 50 hours at the water temperature ranging from 20 to 24℃. The newly hatched larvae measured 4.1 to 4.3 mm in total length. The larvae were fed three days after hatching with a kind of rotifer previously cultivated and several kinds of marine zooplankton. These were replaced about 10 days after hatching by the second food, several kinds of small fish, and then, about 4 weeks after hatching these were replaced by the third food, several kinds of minced fish. Under best conditions, the larvae grew up to 14 mm in total length in 10 days, to 74 mm in 20 days, to 106 mm in 30 days, to 219 mm in 42 days, and to 290 mm in 99 days after hatching. Stages up to 290 mm in total length are shown in Table 1, Fig. 1 and Plates 1 and 2.[著者抄録]1. 1973年5月から6月までの間、和歌山県串本町大島樫野定置網で採捕されるハガツオから、採卵・人工授精を行ない、授精卵を同県白浜町本学水産研究所へ輸送し、ふ化および仔稚魚の飼育実験を行なった。2. 5～6月(水温18～20℃)に紀伊半島南部に来遊し、樫野定置網で採捕されるハガツオから熟卵が採取され、人工授精･ふ化ができることが明らかとなった。3. 卵は直径1.32～1.45mmの分離浮性で、十数個の油球をもち、水温20～24℃で約50時間でふ化した。4. 仔魚は、シオミズツボワムシ･海産動物性プランクトン･小形の生きた魚･魚肉ミンチ･冷凍小魚などを採取して成育し、ふ化直後全長4.2mmの仔魚は、良い条件下では、ふ化後10日14mm、20日74mm、30日106mm、42日219mm、99日290mmに成長した。5. 本実験の結果、ハガツオの採卵･人工ふ化および仔魚飼育の方法が明らかとなり、人工種苗生産の可能性が実証されたが、共食いの激しさも明らかとなり、マグロ頬の他の魚類の人工ふ化･仔魚飼育研究上参考となると思われる知見が得られた。
1974-03-15

ハガツオの人工ふ化と仔稚魚の飼育

スポンサーリンク

概要

著者

関連論文

スポンサーリンク