"合信"牌欧鳗配合饲料精养缓长型欧鳗的试验

本文报告了"合信"牌欧鳗配合饲料精养缓长型欧鳗的试验.结果表明，试验组的平均饲料效率为48.11％，比对照组提高了10.71％；欧鳗的存活率达99.9％，且有较好的肉质，符合出口烤鳗的要求.     

欧洲鳗鲡"狂奔病"的病因探讨

利用组织病理、微生物、血液电解质、寄生虫检查方法对欧鳗"狂奔病"进行分析，发现无论是淡水养殖还是海水网箱养殖，病鳗的组织病理变化基本一致，鳃、肠破坏较为明显，肝、脾、肾、心均有不同程度的充血.从微生物学的分析来看，病毒的检出率并不高，形态也不一致，细菌和寄生虫的感染多样化.病鳗的血液电解质检查结果较为一致，主要以氯离子降低为主，下降幅度在30％～50％之间.由此认为本病不象是病毒、细菌和寄生虫所致.     

僵鳗促长饲料养殖日本僵鳗及欧鳗的效果

将僵鳗促长饲料分别按１％￣２％比例添加于常规鳗鱼配合饲料中进行了养殖日本僵鳗及欧鳗试验。结果表明,饲料效率日本僵鳗添加组比对照组提高了３１％￣４０％;欧鳗添加组比对照组高出６８．９％￣２５０％。成活率日本僵鳗添加组高于或等于对照组;欧鳗添加组比对照组高出５２％￣６２％。养殖每公斤鳗的饲料成本,日本僵鳗添加组比对照组下降了１３％￣２０％,而欧鳗添加组比对照组下降了３６％￣５４％。证实了用僵鳗促长饲料     

"868"菌粉作饲料添加剂提高甲鱼免疫力

以0.5％量添加"868"菌粉作甲鱼饲料添加剂，喂养3个月，用甲醛灭活的嗜水气假单胞菌免疫后，观察甲鱼抗体产生和中性白细胞吞噬能力的变化情况.结果表明，"868"菌粉可促进甲鱼抗体产生，且甲鱼白细胞吞噬率提高了4.1％，吞噬指数提高了8.4％.     

"海马"牌配合饲料喂养大黄鱼的试验

本文笔者于2000年5月17日至7月5日在霞浦海区网箱养殖大黄鱼中，进行"海马"牌配合饲料(按不同比例搭配小杂鱼)喂养大黄鱼试验.结果表明在相同的管理和养殖条件下，10％幼鱼粉搭配90％小杂鱼、50％幼鱼粉搭配50％小杂鱼、膨化饲料搭配小杂鱼在提高大黄鱼的生长速度、存活率和降低养殖成本方面均优于单一使用小杂鱼.     

大蒜素在水产饲料中的应用

概述大蒜素抑菌防治鱼病的药理及其诱食、促生长，提高罗非鱼和缓长型欧鳗饲料效率的研究成果.推理提示大蒜素刺激增强欧鳗胃肠道蠕动与增进雌激素作用的综合生理效应可能是提高缓长型欧鳗饲料效率的因素之一.建议在海水鱼OMP饲料中添加大蒜素与硫胺素防止海水养殖鱼类的B1缺乏症.大蒜素推荐用量为(80～300)×10     

欧鳗黑仔阶段生态养殖初报

本文论述引进欧鳗苗养殖的情况，总结养殖失败的原因及成功者的经验，然后用生态方法对欧鳗黑仔进行养殖。经过２个月养殖，死亡率仅０．１％，平均月增长２倍，饲料效率７５．６９％。     

欧鳗“狂游症”病毒的细胞定位与超微病变

应用电镜标本制备和观察技术对45尾“狂游症”欧鳗的主要脏器进行系统观察，在脑、心脏、肌肉和皮肤组织中，发现一种致病性病毒，多数病毒定位于细胞的内质网腔，一般为球状或椭圆球状，大小约为50～80nm×100～150nm，具有囊膜，囊膜外附有纤突，可以造成脑细胞的肿胀、空泡变性和心肌细胞线粒体的结构破坏和空泡化等细胞病变．人工感染欧鳗中找到同样病毒，表明该病毒是欧鳗“狂游症”的致病原．     

鳗饲料添加螺旋藻粉的养殖效果

本文报道了用Ｓｐｉｒｕｌｉｎａ ｐｌａｔｅｎｓｉｓ粉添加于“厦清”、“大昌”牌养鳗饲料中喂养日本鳗苗的试验。结果表明,添加该藻粉２．０％喂养僵鳗３０ｄ,其饲料系数比对照组均下降,降幅为２１．２％￣５３．７％,鳗增重倍数提高０．０２９￣０．１７１;添加该藻粉２．５％￣２．０％喂养正常幼鳗１１８ｄ,其饲料系数分别降低０．０７４￣０．２３４和０．０２４￣０．１８１,且鳗个体均匀,规格较大。     

"银祥"牌大黄鱼慢沉饲料养殖大黄鱼试验

本文报告了用"银祥"牌大黄鱼慢沉饲料和鲜活饲料进行为期50d的大黄鱼(Pseudosciaenacrocea)养殖对比试验.结果表明，慢沉型颗粒饲料较适合大黄鱼的摄食习性和营养需求，有较低的饵料系数(1.62)，较高的存活率，降低了饲养成本，减轻了对水质的污染，明显地提高了大黄鱼网箱养殖的经济与生态效益.     

Reexamination of the spawning migration of Anguilla dieffenbachii in relation to water temperature and the lunar cycle

ABSTRACT

The oceanic spawning migration of female Anguilla dieffenbachii eels was previously studied using pop-up satellite transmitting tags (PSAT). The swimming depths and experienced-temperature data of 3 eels released in May 2006 were re-examined in relation to water temperature data, and also lunar cycle and regional hydrography as these latter aspects were not considered in the original study. Eel 2 and Eel 3 initially experienced lower water temperature above 600?m, suggesting they remained south of the subtropical-convergence front longer than Eel 1. Their experienced nighttime minimum depths showed linear relationships with the lunar cycle, because they swam shallower during new moon than during full moon. The eels experienced narrow deep-day temperature ranges at a wide range of depths compared to experiencing narrow shallow-night depth ranges where temperatures varied more widely, indicating that several different factors determine their day and night depth ranges.     

Blood oxygenation in shortfin eels during swimming and hypoxia: Influence of the root effect

Blood samples were withdrawn from dorsal aortic cannulae in shortfin eels before, during, and after acute exposure to hypoxia and to forced swimming. Both hypoxia (PIO₂ < 40 mm Hg) and forced swimming at 24 cm s^‐1 abolished apnoeic periods and increased ventilation. The fall in PaCO₂with hyperventilation, raised pH and thus increased the oxygen carrying capacity of arterial blood. The Root effect influences shortfin eel blood up to pH 8.0, at 17°C and has an effect on arterial oxygen content. It cannot be responsible for all of the increased oxygen content during swimming and in recovery from swimming and hypoxia; ventilatory and/or circulatory changes must account for the rest. Hypoxia, but not swimming, produced a rise in dorsal aortic blood pressure. The bradycardia of hypoxia was deeper than that which accompanies apnoeic periods in air‐saturated water.     

Seasonal differences in catches of leptocephali in the East China Sea and Suruga Bay, Japan

The species composition, distribution, and size of eel larvae, or leptocephali, caught near the continental shelf in subtropical and temperate regions of East Asia were compared between two seasons (May–Jun and Oct–Dec) to learn about the seasonality of reproduction of marine eels. There was greater species richness and evidence of spawning by more species of marine eels during the late autumn surveys in both the East China Sea (ECS) and in Suruga Bay along the east coast of Japan. Small leptocephali <10 mm TL and a wide range of sizes of various taxa were collected during both seasons along the outer edge of the continental shelf in the ECS, indicating that some marine eels may spawn there all year. The lack of small leptocephali during the spring survey in Suruga Bay suggested that most eels have a clear seasonal cycle of summer or autumn spawning at the higher latitudes of coastal Japan where there is much greater fluctuation of water temperature throughout the year than in the ECS. At lower latitudes such as in the ECS, and in tropical areas where water temperatures are higher and more constant, some marine eels may spawn all year round.     

Implications of facultative catadromy in Anguilla anguilla. Does individual migratory behaviour influence eel spawner quality?

European eel (Anguilla anguilla) recruitment is declining dramatically since the 1980s. Causes for this decline are explained by a combination of environmental changes basically affecting oceanic larval stages and a variety of anthropogenic impacts during the continental phase. Today, evidence is growing that poor silver eel quality has a major impact on reproductive success, implying that habitat quality plays a key role in stock decline. Since eels are frequently moving through a variety of different habitats during their life cycle, a better understanding of the implications of individual diadromous behaviour and habitat choice on spawner quality are crucial for management considerations for a stock recovery. The present study tested whether individual migratory behaviour and habitat choice of European eels affect spawner quality. Therefore, the migratory behaviour of 287 European eels from marine, brackish and freshwater stations in the North Sea, the Baltic Sea and from Northern German inland waters was examined by otolith strontium/calcium analysis. All individuals were classified either as freshwater residents, coastal residents, downstream shifters, upstream shifters or interhabitat shifters. As indicators for eel quality, muscle fat content, infection with the introduced swimbladder nematode Anguillicoloides crassus and body length at onset of spawning migration were assessed. Results indicate that individuals that exclusively inhabited freshwaters had significantly lower muscle fat contents and were more seriously infected with A. crassus than eels that never entered freshwaters. Since high fat contents are considered as prerequisites for a successful transoceanic spawning migration and high A. crassus loads have a negative impact on condition, this study outlines the importance of brackish waters as eel habitats in temperate latitudes. Furthermore, it questions the net benefit of stocking programs for the European eel population, since they include the translocation of eels from coastal waters into freshwaters.     

Is feeding behaviour related to glass eel propensity to migrate?

Several studies have shown that eel diadromy is facultative and that migratory divergences may appear during glass eel estuarine migration. The origin of the differences in migratory behaviour among glass eels remains unclear but initial evidence supports the role of individual energetic and thyroidal status. Even if starvation is usually associated with glass eel migration, feeding does seem to occur in some glass eels. The aim of the present study was to investigate feeding behaviour and glass eel growth in relation to the propensity to migrate. Feeding rate and weight gain were higher in fish having a high propensity to migrate (M⁺ fish) than in fish having a low propensity to migrate (M⁻ fish) in fed glass eels, whereas no clear difference in the variation in body weight was observed among unfed fish (controls). M⁻ fish initially had lower percent dry weight than M⁺ fish, which suggests a link between appetite, propensity to migrate, and energy content. We discuss the role played by endocrine signals on these processes. In fish, thyroid hormones contribute to the control of growth and development. In addition, they play a role in flatfish and leptocephalus metamorphosis and appear to be involved in smolt and glass eel migratory behaviour. As such, they represent a good candidate which would promote the propensity to migrate as well as digestive system development. Their role in the hormonal control of food intake however remains vague.     

Neurophysiological control of swimming behaviour,attachment and metamorphosis in black-footed abalone (Haliotis iris) larvae

Experiments were conducted to test the effect of a range of chemicals on larval responses in swimming behaviour, attachment and metamorphosis of the black-footed abalone (Haliotis iris). The effect of antibiotics on larval survival was first tested within negative (filtered seawater) and positive (GABA at 10^?5, 10^?4 and 10^?3 mol L^?1) control assays over 3 days. This experiment corroborated the effectiveness of using antibiotics to improve survival of larvae without obvious synergistic interactions with the GABA inducer or confounding effects of potential bacterial interactions. Chemical treatments (acetylcholine, potassium chloride, dopamine and glutamine) were then tested at various concentrations for their ability to modulate swimming behaviour and induce larval attachment and metamorphosis over 14 days. Generally, larval state shifted from swimming to attached, and from attached to metamorphosed, in the control and treatments over time. However, the peak percentage of attached and metamorphosed larvae varied in time among chemicals and concentrations. While overall percent metamorphosis was minimally enhanced after 14 days of exposure to some chemical treatments at certain concentrations, all treatments displayed significant capacities to down-regulate larval swimming and induce early attachment and metamorphosis. Mortality was recorded throughout the duration of the experiment, and was generally low (<20%) across controls and most treatments for exposures of less than 12 days. Interpretations of specific results from this study are used to elucidate neurophysiological control of larval activities for this abalone species. Comparisons with other marine invertebrates highlight the specificities of chemical cues and endogenous regulatory mechanisms across relatively closely related taxa.     

Habitat use by the European eel Anguilla anguilla in Irish waters

The apparent use of marine and freshwater habitats by European eel Anguilla anguilla was examined by analyzing the strontium (Sr) and calcium (Ca) concentrations in otoliths of the eels collected from Irish coastal and fresh waters. The age and growth of eels were also examined using their otolith annuli. The sizes and ages of the female eels were greater than those of the males. The somatic growth rates ranged from 15 to 62 mm/year, which is typical for Ireland and other European countries. Analyses of Sr:Ca ratios along a life history transect in each otolith showed peaks (maximum more than 25 × 10⁻³) between the core and elver mark corresponding to the period of their leptocephalus and early glass eel stages in the ocean. Outside the elver mark, the Sr:Ca ratios indicated that eels had remained in different habitats that included freshwater (average Sr:Ca ratios, 0.98–1.78 × 10⁻³) and areas with relatively high salinities (average Sr:Ca ratios, 6.73–8.89 × 10⁻³). Some individuals showed clear evidence of shifts from sea to fresh waters. These findings suggest that Irish eels have the same behavioral plasticity regarding whether or not to enter freshwater or remain in marine environments as has been recently documented in this species and several other temperate anguillid species. However, patterns of habitat use in Irish waters were somewhat different than those previously reported for other habitats.     

欧鳗(Anguilla anguilla)饲料

本文初步概述饲养欧洲鳗鲡（Anguillaanguilla）的食性特征，对蛋白质的表现消化率和日粮蛋白质的需求量、驯饵、饲料形态、给饲率以及实用的欧鳗配合饲料。建议采用膨化颗粒饲料，制订欧级饲料实验方法和条件的规范。