著者

藤田 矢郎

出版者

The Ichthyological Society of Japan

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

vol.13, no.4, pp.162-168, 1966

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1965年6月22日, 長崎市郊外の野母崎沖でサバフグの入工授精を行い, ふ化仔魚を約1か月間飼育し, 卵発生およびふ化仔魚について次の結果を得た。<BR>1. サバフグの卵は無数の小油球からなる油球塊を有する無色透明な球形の沈性卵で, かろうじて認められる程度の微弱な粘着性があり, 卵径0.61-0.70mm, 平均0.65mmである。<BR>2. 水温21.7-24.5℃で, 授精後67時間でふ化する。本種の卵発生においては, 発生後期・に油球の癒合が行われ, ふ化直前には大油球2-3個と小油球1-2個になるが, これは他のフグ類 (Fugu属およびSphoeroides属) の卵発生にはみられない特異な現象である。<BR>3. ふ化直後の仔魚は全長1.91mm, 筋節数8+13=21で, 卵黄は細長い楕円形で, 大油球2-3個と小油球1-2個があり, 魚体はやせ長い。<BR>4. ふ化後24時間頃から, 仔魚膜鰭は異状に発達し, 頭胴部においては特に巾広くふくらむが, これは本種の仔魚前期の特徴の一っで, 顕著な浮游生活と関連があるのではないかと推測される。<BR>5.ふ化後5日, 全長2.40mm内外で卵黄を吸収し仔魚後期に入る。<BR>6.ふ化後96時間でニワトリの卵黄に, 9日でブライ・ンシユリンプのノウプリウスに餌付きし, ふ化後26-31日で全長6.6mm前後になり稚魚期に達する。

著者

藤田 矢郎 北島 力 林田 豪介

出版者

The Ichthyological Society of Japan

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

vol.33, no.3, pp.304-315, 1986

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<I>Cynoglossus abbreviatus</I> spawns from mid-March to mid-April in the Sea of Shimabara in Kyushu. During the spawning season ovarian maturation was successfully induced by injection of the pituitary homogenate of <I>Hypophthalmichthys molitrix</I>. The dose of the aceton-dried pituitary homogenate was 6.5 mg/kg body weight of <I>C. abbreviatus</I>. It took about 2 days for ovulation after injection at a water temperature of 14 to 16&deg;C. Artificial fertilizations were accomplished on March 29, 1974 and again on April 7, 1984, using the females matured by hormone injection in the latter case only. The larvae were reared on the rotifers, <I>Artemia nauplii</I>, <I>Tigriopus japonicus</I> and copepods collected from the sea over a period of 113 days in 1974 and 58 days in 1984. The eggs were pelagic, spherical, 1.19-1.23 mm in diameter and had 30-50 oilglobules of 0.068-0.095 mm in diameter, and the perivitelline space was narrow. The incubation period was 90-98 hours at a water temperature of 14 to 16&deg;C. The newly hatched larvae were 3.18-3.45 mm TL and had 61-64 myomeres. The larvae had many melanophores and xanthophores on the body, forming three bands on the caudal region, but were lacking chromatophores on the finfolds. The yolk was completely absorbed when the larvae attained a size of 4.7-5.6 mm TL 8 days after hatching. A single elongated dosal fin ray developed on the head in the 8-day old larvae. The ray was reduced in size as long as the other rays 1 or 2 days after metamorphosis. The rudiment of pectoral fins were found on the both sides of the body in the 2-day old larvae, but two of them disappeared after metamorphosis. A pelvic fin first appeared as a ventral bud just anterior to the gut in the larva of 8.39 mm TL. The full count of 4 rays was observed on the larva of 10.83 mm TL. Metamorphosis began 22 days after hatching when the larvae were 11.20 mm TL. The right eye began to shift the left side of the head at night and reached to the final place after 8.5 hours. It took about 36 hours to complete the metamorphosis, including the eye movement and fusion of the hole in the rostral beak. At the last stage of metamorphosis, the dosal, caudal, anal and ventral fins became confluent. The larvae reached the juvenile stage at a size of 13.5-14.0 mm TL, approximately 28 days after hatchling. The growth of larvae reared in 1974 is expressed by the following equations:<BR>Y<SUB>1</SUB>=3.448&middot;1.0507<SUP>x</SUP> (8&le;X&le;28)<BR>Y<SUB>2</SUB>=6.3322&middot;1.0275<SUP>x</SUP> (28&le;X&le;75)<BR>where Y is the total length (mm) and X is the number of days after hatching. Growth rate changed after metamorphosis.

著者

藤田 矢郎 阿部 宗明 道津 喜衛

出版者

公益社団法人 日本水産学会

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.58, no.9, pp.1621-1625, 1992 (Released:2008-02-29)

参考文献数

7

被引用文献数

1 1

著者

中里 靖 藤田 矢郎

出版者

日本水産増殖学会

雑誌

水産増殖 (ISSN:03714217)

巻号頁・発行日

vol.33, no.4, pp.230-239, 1986-03-25 (Released:2010-09-07)

参考文献数

12

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1.新たににテングヨウジが房総の河川にに分布することを明らかににした。2.23.0℃の水温ににおいて淡水から海水への適応にには途中1/2海水にによる2~3日の馴致期間が必要である。3.酒匂川ににおいて1984年9月22日, 育児嚢内にに卵を付着させた雄を採集し, 自然産卵が行われていることを明らかににした。4.水温23.0℃の飼育水槽中ににおいて約1週間ごとにに産卵が行われ, 1984年10月25日から2月11日までにに同一組合せの雌雄にによって12回産卵が行われ, 産卵行動を観察した。1回の産卵数は18~287粒であった。5.上記の卵ににより卵内発生及びふ化仔魚の形態を観察した。本種の受精卵は無色透明の楕円形卵で長径1.16±0.07mm, 短径0.91±0.07mm, 多数の小油球がある。水温23.0℃で受精後156~171時間でふ化する。ふ化直後の仔魚の全長は4.68~5.20mmであった。6.ふ化仔魚の飼育ににおいて, シオミズツボワムシの摂餌は認められなかったが, ムラサキイガイの幼生の摂餌は確認できた。しかし飼育開始数日後ににはすべてへい死した。

著者

藤田 矢郎

出版者

日本水産増殖学会

雑誌

水産増殖 (ISSN:03714217)

巻号頁・発行日

vol.34, no.1, pp.9-14, 1986

著者

藤田 矢郎 与賀田 稔久

出版者

The Ichthyological Society of Japan

雑誌

魚類学雑誌 (ISSN:18847374)

巻号頁・発行日

vol.30, no.4, pp.426-434, 1984

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The present paper deals with ovarian maturation by hormone injection and morphological development of the amberjack, <I>Seriola aureovittata</I> Temminck et Schlegel.Ovarian maturation of the amberjack during the spawning season was successfully induced by injection of either "Gonatropin7" (Teikoku Zoki Mfg.Co.Ltd.), or <I>Hypophthalmichthys molitix's</I> pituitary homogenate, or H.molitrix's pituitary homogenate combined with "Gonatropin".The last dosage was evaluated to be the most effective and reliable.The spawning period seemed to ex-tend from late April to the mid-May in the Sea of the Goto Islands.On May 14, 1977 the authors performed artificial fertilization of the specimens which were artificially induced to mature by the hormone injection, and reared the hatched larvae to grow to the juvenile stage.The eggs of the amberjack are pelagic, spherical in shape and 1.27-1.50mm in diameter.The yolk is roughly segmented and contains a single colorless oil globule of 0.34-0.36mm in diameter.The perivitelline space is narrow.During embryonic development, many melanophores and xantho-phores appear on the embryo and oil globule.Hatching took place in 96 hours after artificial fertilization at water temperatures between 15.5 and 20.4°C.The newly hatched larvae were 4.45-4.55mm TL and had 26 (12+14) myomeres.Characteristic features at the larvae were that the oil globule was situated at the anterior part of the segmented yolk which was extended slightly beyond the head and that the granules existed on the marginal fin which was densely pigmented with xanthophores.The yolk was almost all absorbed when the larvae attained 5.23-5.45mm TL, 4 days after hatching.In a 9-day old postlarva, 6.25mm TL, small denticles appeared on the margin of the upper jaw and there were 4 opercular spines on the preoperculum.In a postlarva 19-days after hatching, 7.5mm TL, the notochord was turned up and caudal, dorsal and anal fins with rudiments of rays were beginning to develop.In a 30-day old juvenile, 15mm TL, the coloration of the body was pale greyish black with the characteristic 2 yellow bands situated at the anterior part of the trunk and the caudal region.In a juvenile of 40-days, 23mm TL, 3 4 greenish dark brown cross bands appeared on the posterior part of the side of the body.The number of the bands increased to 7 at a size of 45mm TL, but such bands had disappeared in a specimen of 195mm TL.

著者

福所 邦彦 藤田 矢郎

出版者

日本魚類学会

雑誌

魚類学雑誌 (ISSN:00215090)

巻号頁・発行日

vol.19, no.1, pp.32-33, 1972-06-25 (Released:2010-06-28)

参考文献数

8

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In the waters of Tsushima Island, young of dogtooth tuna, Gymnosarda unicolor (Riippell) which were gathered underneath the lurelamp were captured by squid fishing boats on 25 th July, 1970.Since then, the young were caught by surface trolling and set net, and the capture continued to early January 1971.Their size increased as season went on: 24.0-27.5 cm in fork length and 200-300g in body weight in early August;36.0-39.5cm in fork length and 640-910g in body weight in late November;41.0-45.0cm in fork length and 1115-1170g in body weight in the middle of January.But they have not been caught since January of: 1971.This species had been unknown among the fishermen working around Tsushima Island. This region is outside of their distribution area previously informed by some authors. Therefore, it is highly probable that the occurrence of this species is recorded in the first time here.