アイソザイム系遺伝子による遺伝情報により, スズキ属魚類3種 (スズキ, Lateolabrax japonicus, 中国産スズキ, L. sp., ヒラスズキ, L. latus) の遺伝的分化について調べた。L. latusはL. japonicusおよびL. sp.との間でADH^*, EST-2^*, GPI-1^*, PGM^*, PROT-1^*, PROT-2^*, SOD-1^*の7遺伝子座において対立遺伝子の完全置換, MEP遺伝子座では遺伝子頻度の著しい相違がみられ, L. japonicusとL. sp.の種間の遺伝的分化の程度よりも相当に高い水準でこれら2種と分化していた。また, L. latusはL. japonicusとFBALD-1^*とFBALD-2^*の2遺伝子座で共通の主対立遺伝子を持ち, L. sp.とはLDH^*の1遺伝子座で共通の主対立遺伝子を持っていたことから, いくぶんL. japonicusの方に遺伝的に近いことが示された。これら3種の遺伝的類縁関係より, L. latusがこれら3種の共通の祖先種から最初に種分化し, その後かなりの年代を経過した後にL. JaponicusとL. sp.が分かれたものと考えられた。

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特殊な形態を示す上鯰越池のオオクチバスと他の湖沼の集団との形態的, 遺伝的比較を行なった。上鯰越池の集団は多くの形態形質において他の集団と差が認められ, 各形質の分散が小さい傾向が認められた。遺伝形質では, 各集団ごとに独特な遺伝子組成を示し, その母体となった親魚数が少なかったことに起因する遺伝的浮動による影響の可能性が示唆された。特に, 上鯰越池の集団はアイソザイム系遺伝子座において遺伝的変異が全くなかったことから極めて少数の親魚から派生した集団であるものと推定され, たまたま形態的に特殊な数少ない親魚が放流されたことによりこのような集団が形成された可能性が考えられた。

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オニオコゼの飼育仔稚魚について, 遊泳と摂餌にかかわる形質の形態発育を記載し, 発育段階の設定を行った。まず, 遊泳機能に関する形質の発達に基づくと, オニオコゼ仔稚魚は以下の5段階に分けられた。1) 遊泳未発達期 (ふ化～体長3.6mm [D-0～D-1] ) : 遊泳機能に関する形質としては, 膜鰭からなる鰭だけが出現した; 2) 胸鰭遊泳期 (体長3.6～4.7mm [D-1～D-8] ) : 胸鰭の支持骨と胸鰭鰭条が出現し発達する時期; 3) 移行期 (あるいは尾鰭準備期, 体長4.7～5.6mm [D-8～D-12] ) : 脊索の末端部が上屈し, 尾鰭の支持骨と鰭条が出現, 発達する時期; 4) 尾鰭推進期 (体長5.6～7.0mm [D-12～D-18] ) : 脊椎骨が出現, 発達し, さらに背鰭と臀鰭の支持骨と鰭条が出現, 発達する時期; 5) 完成期 (体長7.0-7.5mm以上 [D-18-20以降] ) : 稚魚としての遊泳能力を獲得すると考えられる。さらに, オニオコゼ仔稚魚は, 摂餌機能に関する形質の発達に・基づいて, 以下の5段階に分けられた。1) 摂餌未発達期 (ふ化～体長3.6mmまで [D-0～D-1] ) : 仔魚は未開口で, 栄養は完全に内部栄養に依存する時期; 2) 吸い込み期 (体長3.6～5.1mm [D-1～D-8] ) : 口腔を形成する基礎的な構成要素が出現し, 口腔内の陰圧を利用して摂餌する時期; 3) 移行期 (あるいは吸い込み発達期, 体長5.1～約6mm [D-8～D-15] ) : 口腔構成要素の化骨や鰓蓋骨の出現で口腟内の陰圧がより強くなり, また前上顎骨と角骨の出現で口の開閉がより機能的になる時期; 4) 噛みつき期 (体長約6～8mm [D-15～D-21] ) : 口裂に占める前上顎骨の割合いが一定になり, さらに顎歯と咽頭歯, 前鋤骨歯が出現することで, より機能的な顎の開閉と噛みつきによる餌の捕獲が可能となる時期; 5) 完成期 (体長約8mm以上 [D-21以降] ) : 稚魚としての摂餌能力を獲得すると考えられる。以上のように, 遊泳・摂餌機能の発達からみると, オニオコゼの仔魚から稚魚への変化は, 体長7.5～8.0mm以上 (D-20-21以降) であると判断された。なお, 各鰭の鰭条の定数という観点からみたオニオコゼの仔魚から稚魚への変化は, 体長6.2mm (D-17) であった。

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二次元泳動地図におけるスポット出現時期によりサクラマス (ヤマメ) の胚発生過程を特徴づけることを目的に, 受精からふ化に至る35日間の二次元泳動地図間の706個のタンパク質スポットを対応づけた。N末端配列を決定した11個のタンパク質スポットのうち9個のスポット (ID=7, 8, 423, 502, 512, 522, 528, 570, 601) のN末端配列は, ニジマスのビテロゲニンタンパク質の部分配列と高い相同性を示した。そのうちの2個のスポット (502, 512) は出現時期において正常胚と半数体胚において差があるという知見から, これら2個のスポットの正常な胚発生過程を示す指標として重要であることが判明した。さらに, 受精後23日目に出現する2個のスポット (58, 324) のN末端配列からそれぞれのタンパク質機能を推定するとともに, 後者のスポットの正常な胚発生過程を示す指標としての有効性について考察した。

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放射免疫拡散法 (SRID) による簡便かつ特異性の高いマダイ, Pagrus major, のビテロジェニン (Vg) 定量法を開発した。本SRIDには, マダイ卵黄蛋白に対する特異抗血清を用いた。各種の抗血清濃度, Vg量および反応時間を検討した結果, 抗原抗体反応完了時における免疫沈降輪の面積は, 試料中のVg量に比例することが明らかとなった。一方, 抗原抗体反応が未完了の時点では, 試料中のVg量と免疫沈降輪の面積との関係を対数式で表現できることが明らかになり, 測定時間の短縮および抗血清の節約が可能となった。抗血清濃度1%, 反応時間1日におけるVgの定量可能範囲は, 21μg/mlから42.4mg/mlであった。同条件下におけるアッセイ内変動係数およびアッセイ間変動係数は, 各々1.71% (n=9) , 4.85% (n=5) であった。また, エストロジェンによる雄マダイのVg産生誘導, 卵黄形成における雌マダイ血清中のVg量の変化についても検討した。

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カマキリとヤマノカミの成長および生残率と水温の関係を明らかにするために, 天然河川で採集した供試魚を用いて短期間の飼育を行った。
カマキリの場合, 低水温区の20℃区が最も優れた成長と生残率を示した。逆に高水温区の27℃区は短期間で生残率が急減し, 成長も他の水温区に劣った。ヤマノカミの場合, 20～28℃の全区で生残率の急減は認められなかった。しかし, 成長では明らかに差が認められ, 20℃区と24℃区が28℃区に比べ優れていた。したがって, 生存可能な限界水温はカマキリでは24～27℃に, ヤマノカミでは28℃以上にあり, 成長のための至適水温は3区の中では20℃前後であると推察された。

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Size distribution in body length of 7, 376 juvenile nibbler, Girella punctata Gray captured in the period from March to August, 1981, 1988, 1996 and 1997 at coastal waters of Izu Peninsula was analyzed for a better understanding of their population dynamics. In March and April, the fish captured at rocky beaches was significantly larger than those at breaking zone and tide pools. However, during the period from March to August, the smaller fish also joined the rocky beach population and those ranging from 1 to 2 cm were always found at breaking zone and tide pools. These results strongly suggest that the juvenile nibbler change their inhabitation from breaking zone and tide pool to rocky beaches as they grow up.

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A total of 61 aeromonads, including A. caviae, A. hydrophila and A. sobria, isolated from six freshwater cultured fishes, were examined for the ability to produce fatty acids from glucose. The amounts of fatty acids produced varied with bacterial species. All the isolates produced lactic acid as a major product, and 88 to 94% of Aeromonas species produced acetic acid to a lesser extent. Moreover, it is found that even within genospecies significant strain-to-strain variation exists in amounts and composition of fermentation products.

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The death of scallops reared in farms in China from July to August, 1996 and 1997 was found to be associate with vibriosis. The disease which led to a mortality of 20 to 50% of the cultured population occurred among shells with a body weight of 180-220g. The characteristics of the bacterial isolates from the adductor muscle of the infected specimens was closely correlated to that of Vibrio alginolyticus. In the bacterial challenges experiment using the immersion method, the specimens challenged with doses over 1.0×10⁶ CFUIml died within 14 days after immersion.

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A fungus was isolated from the regions of dermatomycosis on Japanese pond turtle, Mauremys japonica. The fungus was tentatively identified as Aphanomyces sp.of Saprolegniaceae. However, we could not define it at species level because the fungus did not produce any syngenetic organs. The optimal growth temperature for Aphanomyces sp. strain AK11 was estimated as 25-30°C. This is the first report of Aphanomyces sp. infection in Japanese pond turtle.

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Recirculating aquaculture production technology has been the focus of research and development for decades. As suitable area and resources become limiting for traditional pond or net pen based aquaculture, more use of water reuse technology will become prevalent. Before one can design or even operate a system that uses water over and over again, some basic understanding of the engineering and biology of the systems is required. This manuscript is intended as an introduction to recirculating aquaculture systems for those that are interested in fish production in water limited areas.

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Techniques for maturation, spawning and larval rearing of Pacific yellowtail, Seriola mazatlana, were developed in Ecuador during the last five years. Using the methodology described in this paper, we were able to obtain continuous and sustainable year-round spawning of both wild and captive reared broodstock fish in maturation tanks. After collection from the wild and acclimation for about one year at the hatchery facilities, one group of twelve broodstock fish was producing about 400, 000 fertilized eggs twice a week over a 18-month period. Another group of ten wild broodstock fish spawned 4, 500, 000 fertilized eggs per month from February to October, 1997. Similar results were achieved with a third group of twelve wild caught broodstock fish in another commercial hatchery in Ecuador. During 1997, 50 months after hatching, we were able to get a hatchery grown group of brood fish (first generation in captivity) to spawn about 200, 000 fertilized eggs twice a week in captivity. Larval husbandry was conducted using three different techniques: intensive, semiintensive and extensive. Results have been highly variable. Depending upon the egg quality from the different batches, survival rates ranging from 0-70% were achieved throughout larval rearing of Seriola until metamorphosis. High mortalities of fingerlings and early juveniles after metamorphosis have been lowering the average survival rates through the juvenile stage to 0.5-2.0%. Epitheliocystis has been shown to be the most important disease to occur during early developmental stages. Epizootics of this disease have caused mass mortalities of fingerlings. Other factors directly or indirectly related to the high mortality rates observed are broodstock nutrition, variability in egg quality among different batches, larval nutrition, weaning from live feeds onto artificial diets, as well as high levels of cannibalism after metamorphosis. Commercial production of Pacific yellowtail in Ecuador and other Latin American countries has been hampered exclusively by high mortalities of fingerlings and early juveniles. All other technicalities related to their aquaculture are thought to be mastered. The technological feasibility of Pacific yellowtail aquaculture has been proven. The commercial, economical viability of the operation remains uncertain.

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The ability to fully control sexual maturation and spawning is a primary requirement for successful aquacultural production. The artificial induction of spawning either by hormonal or environmental manipulation enables supplies of eggs and fry, sometimes generically referred to as seed, to be made available even from those fish which do not naturally spawn in captivity. For species of fish which are able to mature and spawn under farm conditions, controlled reproduction can provide seed at precisely those times required by ongrowing farms and not just during the few months of the year when natural spawning occurs. In turn the availability of seed on demand enables grow-out farms to spread their production of market-sized fish throughout the year.
Effective seed production also demands a thorough understanding of the special husbandry and nutritional requirements of broodstock fish because diet and management procedures can have significant effects on fecundity (numbers of eggs produced), egg size and egg and larval quality or survival.
In addition to being able to produce good quality seed on demand it is also essential that farmers are able to control the gender or sex of the seed which is produced. This ensures that the metabolic activities of the fish produced from this seed and more importantly the inputs of high cost artificial feeds are wherever possible channelled into the growth of saleable flesh and away from gonadal growth and sexual maturation.
The ability to both control the timing of spawning and to determine the sex of the progeny assumes a greater importance with the intensification of fish farming. Generally, intensification demands greater tonnages of production in order to reduce unit costs through economies of scale. This greater volume of product has to be retailed through the chain multiple or supermarket stores with less reliance on local or farm gate sales. Such markets require a continuity of supply of fish of consistent size and quality throughout the year. Continuity of supply is only possible when the control of reproduction of the fish under cultivation allows input of seed to be made at any time of the year. Avoidance of the problems of maturation also enables farmers to meet the strict product specification relating to fish size and flesh quality invariably imposed by retail organisations.
Given the importance of effective broodstock management in the provision of all-year-round supplies of seed in modern aquaculture, the present review will consider the basic mechanisms of controlling reproduction, gender and smoltification and describe how these may be modified by photoperiod and melatonin and other hormonal and dietary influences to optimise supplies of seed.

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Fishes are extremely sensitive to pineal regulation because they are practically the only modern vertebrates possessing pineal photoreceptors. This peculiarity enables to realize the unique way of photoinformation penetration into fish pineal organ-directly through skull roof bones in comparison with higher vertebrates delivering illumination signal to pineal via neural pathways from lateral eyes. Pineal regulation could be shown to be very useful tool for fish aquaculture optimization. For last 6 years we've fulfilled the complex of experiments at the Crimean State Mountain Reservation Trout Farm to demonstrate the efficiency of pineal regulation for handling melatonin blood and neural levels in artifficial salmonid subpopulations and individual fish specimens and hence- 1) spawning, somatic growth and maturation rates, food consumption efficiency (feeding rate) ; 2) immune status (bacterial and fungal diseases cure without any chemicals) -using various illumination regimens, pineal tissue transplantation (diffusional chambers method) and magnetic field exposure (as pineal tissue is also magnitoreceptive one) .

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Different species of microalgae, the rotifer, Brachionus spp., and the brine shrimp, Artemia spp., are essential live food in the farming of several species of molluscs (e. g. oyster, clam, scallop), crustaceans (e. g. marine shrimp, freshwater prawn, crabs) and fish (e. g. bass, bream, grouper, turbot, flounder, halibut, ayu) . A brief overview is given of the latest developments in their production and use in industrial hatcheries.

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Cephalopods are remarkable among poikilotherms for their rapid growth rates (>10% body weight d^-1 and protein-dependent metabolism. Cephalopods grow at rates equal to homeothermic vertebrates, surpassing by far their main competitors, the pokilothermic vertebrate fishes. Their rapid growth rate (from 10-20 mg to>2 kg in 159 d) is dependent on their carnivorous lifestyle with daily feeding rates averaging 20-40% body weight d^-1 through most of their life cycle. Dietary lipid is utilized poorly and dietary protein supplies their highly aerobic metabolism. As a result, cephalopods produce ammonia rapidly and yet they are extremely sensitive to the nitrogen waste products. Currently, a computer automated control system monitors and controls all system functions (i. e. flow rates, salinity, level pH and photoperiod) . In addition, an automated denitrifying bioreactor is used to reduce nitrate and eliminate water exchanges. The culture of cephalopods in such low ammonia (<0.01 ppm) and low nitrate (<20 ppm) sea water has resulted in multiple laboratory generations. Implementation of artificial diets is also a current area of research; a surimi-like diet supplemented with purified proteins has been used to grow cephalopods at 33% of their normal growth rate. Behaviorally, cephalopods are visually stimulated predators but their chemical senses do play a role in food selection and ingestion. Nucleotides (e. g. ATP, ADP) and the amino acid, proline are the most effective chemicals that elicit chemotaxis in octopuses and squids and they are incorporated into artificial diets. These advances in cephalopod culture are establishing reliable sources for these important biomedical research models and point to the possibility of commercial culture for food.

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France is the first european producer in aquaculture, with more than 300.000 tons. Oyster production reach 150.000 tons, the third figure in the world. Freshwater finfish attain an annual production close to 70.000 tons, and marine finfish, 5.600 tons.
Recently, production of aquatic animals have shown some important evolutions, as a result of changes in alimentary habits, of sea food market in continental France and overseas territories, of progress of scientific knowledge and technologies, and of free circulation of goods inside the common boundaries of European (EEC) countries.
Some examples of scientific progress are described: better knowledge of biological cycles of cultured species, their nutrition, physiology, biochemistry, genetics, molecular biology, behaviour, as well as their diseases and parasites. Technological success have been obtained, as intensive culture methods and more efficient techniques in culture of molluscs.
Main characters of aquaculture in France are described. Its development in competition with other users of coastal zone, mainly tourism, are pointed out. Physical, chemical and biological characters of the sea water are controlled at the national level by several surveillance networks.
New cursus in education, at different levels, oriented to aquaculture technology, research and production, have been created during these recent years.
New laws have been passed, at national and international levels, in order to regulate the relationships between fishermen and aquaculturists, to protect the natural environment and to promote future aquaculture activities.

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The Yangtze River is the cradle of aquacul-ture and freshwater fisheries in China. This river con-tains 370 fish species, including the high economic chinese carps and rare animals such as Beiqi and sturgeons, provides 60% of freshwater fish production in China.
The natural fishery resources has decreased seriously due to overfishing, hydro-construction and pollution etc. On the other hand, the aquaculture has quite developed not only in Yangtze River delta-one of two traditional aquaculture center in China, but also in many new areas along the middle- and lower-reaches of this river. The pond fish culture and lake fish culture as well as reser-voir fish culture of the Yangtze River basin leads the country.
The Three Gorges dam is a world class hydro-engineering project, will be the most serious factor to threaten the fisheries and aquaculture of the Yangtze River.
Genetic conservation measures have been adopted since 1990s. At present, the major efforts are to estab-lish ecological conserves and pond-type gene banks for the most inportant fish and other aquatic animals, such as major carps, river crab and turtles.

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It has been widely used that the captured and cultivated fish are frozen to preserve for transportation. On the other hand, live fish transportation is popular by decreasing body temperature of fish in order to adjust the Japanese culture. The latter depends on the decrease of metabolic rate by temperature shift down. However, the method limits the amount of transportation and the species of fish. Eventually, the market prices of those are normally high.
There are hibernators in mammals. They hibernate during winter triggered by a certain signal according to the seasonal environmental changes. It is a mechanism to save energy under the severe conditions. Physiological background has not been established on this mysterious phenomenon. The classical experiments showed that the trigger substance (s) was involved in the serum of the deep hibernators, and the substance (s) could induce hibernation even to the summer active mammals. It was thought opioid peptides play the major role in inducing hibernation. Since serum from the deep hibernating mammals did not include opioid peptides, the unknown substance (s) might accelerate the secretion of opioid peptides. Infusion or perfusion of the opioid peptides or the serum into mammals including primates reduced the body temperature and functions of liver and kidney, and induced the long lasting hypophagia.
We examined the effects of serum from hibernating ground squirrels and the opioid peptide, DADLE, with the fish which was non-euthermic, Brook trout, cutthroat, rainbow trout, gold fish, and carp were used by infusing intraperitoneally or osmotic shock with those hibernation inducing substances. Respiration rate calculated from the changes of dissolved oxygen level was typically reduced by the substances and antagonized with naloxone. Serum from the infused fish was also examined routinely and found that the levels of alanine aminotransferase and uric acid were temporally increased. While, aspartate aminotransferase and blood urine nitrogen were decreased. These observations suggest that the functions of liver and kidney were strongly affected by the substances. The effects were antagonized with naloxone indicating that the opiod peptied receptors participated in inducing torpor. We could easily imagine fish had an ability of hibernation but was deficient, and it was a result of re-organization of the existing materials which normally functioned for pain control. Furthermore, the substance can be self-produced in a short time and quickly appeared in the serum. Such ability must have been constructed at the early stage of evolution.
Based on the above experiments, I will discuss on the possibility of application of the method and the future fishery.

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