人工ふ化・育成したイの体側斑紋 (7本の横帯) の形成過程を調べた、形成の様式は天然採集個体について調査した場合の既京とほぼ同一で, その発達は体長に相関することが確認された.まず, 背鰭棘部の中央よりやや後方の基底と肛門の後端を結ぶ線より前方が黒色化する (全長8.1～9.1mm).第1帯一第3帯の上方部が融合した状態で現れ, やがて各帯は分離独立する (9.1～10.0mm).第3帯に連続して発達した黒色素胞の分布帯は, 分離独立して第4帯になる (11.1～12.0mm). 第5帯～第7帯は共通の大斑として現れ, 大斑が第4帯より分離し, 同様にして第5帯が形成され (16.1～17. 1mm), ついで第6帯と第7帯が分離独立し, 全7帯が完成する (18.0mm). 水温18.5～23.7℃で飼育した場合には, 斑紋の形成はふ化後約20日に始まり, 同27～35日に完成する.
イの人工採苗における稚魚の飼育管理の基準としては, ふ化後日数ではなく体長を採ることが妥当であり, 体長と相関して発達する斑紋の特徴が飼育指標として用い得る. 飼育経験上, 全長12mm前後から魚肉に餌付けるとその後の成長が良好であることが判明しているので, 第4帯形成時を餌付け開始の指標とすることが可能である.

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Adult Japanese parrot fish, Oplegnathus fasciatus, mature and spawn in sea pens or aquariums. But artificial induction of ovulation is necessary to get a large amount of fertilized eggs for sex control or induction of polyploidy in order to create new varieties of important species for fish culture. In the present study, maturation and ovulation were induced in Japanese parrot fish with viteliogenic oocytes by using chum salmon pituitary homogenate (5 mg/kg fish) in combination with human chorionic gonadotropin (500 IU/kg fish) given as a single intramuscular injection. A total of 160 female fish was used; hormone injections were carried out on 80 fish and the rest 80 fish were untreated (control), and they were kept with respective 50 mature male fish in each sea pen.
In the fish tested, a high maturation success was achieved one day (94%) and two days after injection (73%), and ovulations were observed in the fish sampled at 23-25 h and 52 h after injection. There were no significant differences in gonad index (GI) and mature egg number (g^-1 ovary) between mature fish one day after injection and mature control fish, but GI and mature egg number in the mature fish two days after injection were significantly lower than those of mature fish one day after injection and mature control. These results suggest that one day (25-29 h) after injection is desirable for the time of stripping. The mean fertilization rate and hatching rate in the control fish just after ovulation (N=6) were 70% and 81%, respectively, but those rates in the experimental fish in the same condition (N=1) were 3% and 0%.

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Multi-heads weighers are used in the packing process of the production lines for various food industry for precise measurements. In this paper, we pay attention to a vibratory dispersive feeder of electro-magnetic type, which is a part of the multi-heads weigher, and we construct control systems for the feeder in order to adjust the amount of conveyed materials by the feeder. First of all, we analyze vibration characteristics of the feeder. Next, we apply PI control scheme and Fuzzy control scheme to control the feeder. As a result, the control systems with PI and Fuzzy controller provides the good responses in the changes of the reference values.

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1) 本邦産シロレイダマシ属2種(シロレマシ)の歯舌を記載し, 有舌腹足類の歯舌には, 顕著な雌雄差の存在する種類があるこを初めて明らかにした.2) シロレマシ属の歯舌は, 他のアクキガイ科の諸種のものとは非常に異った形を示し, 又中歯の形, 歯列比, 中歯の巾と側歯の長さとの比, 歯舌の色等に著しい雌雄差がある.3) 従来, イガレイシ属の下におかれていたヒメシロレマシの歯舌は, シロレマシ属のものに一致するので, 転籍した.これで邦産のシロレマシ, ヒメシロレマシ及びsiderea (Reeve)の3種が含まれることになった.4) シロレマシ2種の歯舌の特徴を簡単に比較して表に示した.

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Behaviour of the Japanese striped knifejaw Oplegnathus fasciatus was studied by underwater observation and tagging experiment at Tajima coast in Japan Sea. The results obtained are as follows ; 1) The fish schools were small on the rocky reef, but were large on the artificial seaweed farm plant. 2) High rates of schooling were shown in juvenile and young fish respectively, both on the artificial seaweed fam plant and on the rocky reef. The rates of schooling on the artificial seaweed fam plant were higher compared with those on the rocky reef. 3) Approximately 92 % of tagged fish were recaptured within l0 km from the released point. 4) It was suggested that small schools and solitary individuals on the rocky reef were sedentary and large schools were migratory. It was also suggested that large schools on the artificial seaweed farm plant were staying there temporarily. 5) An unfavourable environment as sandy bottom seemed to force the fish to aggregate on the structure like the artificial \SeaWeed farm plant and the artificial reef. On the other hand, the large schools broke into smaller ones on a favourable environment as the rocky reef and the fish stayed there for a long period of time.

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Two Oplegnathus juveniles were found among shoals of juveniles attached to the floating patches of seaweeds migrating to Oshima waters in 1969 to 1970.Under investigation of their morphological characteristics, they are presumed to be hybrids between O.fasciatus and O.punctatus, both of which are common in waters of central Japan.

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1977年6月-8月に長崎水試増養殖研究所において, 油脂酵母による栄養強化ワムシを併用したイ仔稚魚の飼育 (実験I), 油脂酵母によるワムシの量産 (実験II), 油脂酵母ワムシによるイの種苗生産 (実験III) を行い, 次の結果を得た。
1) 実験Iでは, 屋外100t円型槽で平均全長24mm (日令39) までの飼育を行い, 計約6万尾の稚魚を生産した。この間にワムシと5) に示す他餌料を順次併用給餌した。
2) ワムシの給餌量はクロレラによる栄養強化ワムシ11億 (日令1-同8), 油脂酵母による同ワムシ190億 (5-25), 油脂酵母ワムシ118億 (18-29) 計319億個体であった。
3) 屋外40t槽を用いた油脂酵母によるワムシの量産では, 1日1槽当りのワムシ生産量は平均5億個体で, 油脂酵母1g給餌当りの生産量は平均10.2万個体 (約0.306g) であった (実験II)。
4) 実験IIIでは, 屋外200t槽で平均全長26mm (日令36) までの省力化を図った飼育を行い, 約22万尾の稚魚を生産した。
5) この間に与えた餌料は油脂酵母ワムシ (日令2-同32), マダイ仔稚魚用配合飼料 (15-35), コペポーダ類 (18-32), 魚介肉ミンチ (24-35) で, 各餌料の総給餌量はそれぞれ268億個体, 11.6kg, 19.3kg, 187.0kgであった。
6) 生産した種苗は従来の方法の場合に比べて活力に優り, 取揚げおよびその後の輸送 (活魚船で約5時間) で斃死する個体がなかった。
7) 油脂酵母は, ワムシの量産とイ仔稚魚への餌料価値の両面でクロレラの代替えとなり, 両者に共通して含まれる脂質の中の少なくともエイコサペンタエン酸 (20:5ω3) がマダイ仔魚と同じくイ仔魚にも必須脂肪酸であることが推察された。

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Temperature preference of 2-14 month old striped beakperch, Oplegnathus fasciatus, (B. L. 3.3-14.9cm) hatched on the same day was tested using a vertical temperature gradient tank. Fish were acclimated to 25°C for more than 18 days before the experiments. Temperature was a dominant factor affecting fish distribution in a vertical temperature gradient, since the distribution was shifted in accordance with the location of preferred temperature. No clear change in the preferred temperature was shown with exposure to the temperature gradient for more than 24 hours. The preferred temperatures were related to the growth of the fish. Two to eight month old fish preferred a progressively cooler temperature from 28.6 to 24.7°C as they grew. Fish older than 8 months preferred a narrower temperature range of 25 and 26°C.

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ピーマンやポテトチップスのように，原料による重量ばらつきの大きい食品生産の現場では， 規定量の袋詰め（充填）に組合せ計量機が使われる．組合せ計量機はホッパと呼ばれる十個程度の小さな箱に小分けにして計量物を投入し，各計量値の組合せの中から規定量に適合するものを見つけて充填する．その歩留まりと稼働率は現場の主要関心事である．本論文は，組合せ計量機を素朴に数理モデル化し，ホッパ数ならびにホッパへの投入量の平均と分散に対する規定量適合の確率について議論する．具体的には，各ホッパへの投入量は独立に同一の正規分布に従うとして，規定量に適合する計量値組合せが存在する領域（実行可能領域）の生起確率（組合せ成功確率）を求めたい．実行可能領域は非凸であり，組合せ成功確率の計算は組合せ論的な難しさをもつ．本論文は，精度保証も考慮してモンテカルロ法を採用し，ホッパ数およびホッパへの投入量の期待値と分散について網羅的に組合せ成功確率を計算して，実データと比較する．現場では経験的に，ばらつきは大きい方がよいとされるが，本モデルの計算結果から，投入量分散が小さいとき，組合せ成功確率は投入量期待値の変化に対して敏感で，すなわち経験知を支持する．

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　1)1975年に腹部ぼう満症状を呈する.マダイ稚魚より分離したVibrio alginolyticus CY-1はマダイ稚魚に疾病をもたらすことが確認され,マダイ稚魚に対し病原細菌を伝播する媒介者としてワムシの疑いが濃厚となった。2) クロレラを添加した海水でマダイ稚魚を飼育した場合は,海水のみで飼育した場合に比較し,生残率が高い傾向に認められた。3) クロレラ添加海水にワムシを添加すると,ワムシによってクロレラが消費され,海水中の細菌が増加する傾向が認められた。

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小笠原諸島父島において, 2003年4月から6月にかけて種苗生産した日齢68のイシガキダイ稚魚 (平均体重3.6g) を254日間養成した。養成期間中の水温は20.3～29.6℃であった。餌料には, 市販のマダイ用配合飼料を用い, 1日1～2回飽食量を与えた。養成終了日の日齢321には平均体重659gに達した。日間給餌率と日間成長率は成長とともに減少した。養成期間中の増肉係数と増肉単価はそれぞれ1.68と362円/kgであった。養成期間中の収容密度は, 日齢188までは約10kg/m³以下であったが, 成長とともに高くなり, 日齢215からは15kg/m³以上, 日齢255からは20kg/m³以上で, 養成終了日には23.5kg/m³であった。養成終了日の生残率は94.0%であったが, 斃死はほとんどが日齢100までの問にみられ, 日齢156以降は養成終了日まで斃死は認められなかった。以上の結果から, 当地では, イシガキダイの養成はふ化後1年以内に商品サイズの430～841gに達し, 本土と比較してコストパフォーマンスに有利であるため, 小笠原諸島父島は本種の養成に適していることが判明した。

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The spawning of captive-reared spotted parrot fish Oplegnathus punctatus obtained from rocky shore waters around Chichi-jima, one of the Ogasawara Islands, was observed during rearing between 2002 and 2003. The two females which participated in the spawning were 3.2 and 4.5 kg in BW. Spawnings were observed on 18 occasions between late April and late June. The water temperature in the entire period varied between 18.8°C and 29.6°C whereas that on the spawning days varied between 21.1°C and 24.6°C. The total number of eggs taken was approximately 7 million. The average rate of buoyant eggs was 82.5±23.7%. The average diameter of the egg and oil globule were 1.045±0.017 mm and 0.245±0.006 mm, respectively.

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There are many problems to be solved for establishment of more reasonable and simplified method of fry production in the marine fish culture.One of the most important subject is to clarify the feeding ecology of larvae and juveniles under rearing condition.In the former works, times required for satiation and digestion in the larvae of Oplegnathus fasciatus (Temminck and Schlegel) were tested.The present paper deals with those examinations in the juveniles with a fairly developed stomach.
The copepod Tigriopus japonicus Mori was used as food.Degrees of satiation and digestion were estimated by counting the number of food organisms in 5 portions of the digestive tract: mouth cavity, stomach, anterior intestine, posterior intestine, and rectum.
Time required for satiation in the juveniles (19.3-20.2 mm in T.L., 36 days after hatching), which were starved for 15 hours, was nearly one hour after the food organisms were supplied at density of 10 individuals/ml.Content of digestive tract amounted 15.8% of body weight when satiated.At that time the stomach contained 80% of the total food.
Times required for digestion (remained content less than 10% of satiation amount) in stomach and digestive tract of the juveniles (19.4-22.8 mm, 37 and 38 days after hatching) were 3 to 4 and 5 to 6 hours, respectively.
The feeding behavior of juveniles seems to show the transitional pattern from that of larvae to that of adults with a full-developed stomach.

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