湛江叉鞭金藻生态条件的研究1．营养盐浓度对湛江叉鞭金藻增殖的影响

１９９０年３月１５日－４月９日在室内自然温度变化条件下（１１－１８℃），采用浓度１－５‰的康威营养盐溶液培养湛江叉鞭金藻。结果表明，３‰浓度对增殖效果最好，经６天培养，细胞密度由６５．５－７６．０×１０４ｍｌ－１。     

中华鳖人工繁殖与饲养（下）

中华鳖人工繁殖与饲养（下）３．稚鳖饲养（１）鳖池规格：稚鳖池必须用砖砌水泥浇制，规格有４×３×０．６ｍ或５×４×０．６ｍ，水深３０～４０ｃｍ，１／２池底放沙厚为１５～２０ｃｍ，１／２底无沙。（２）放养密度：刚出壳稚鳖重３～５克，每平方米密度为６０～８...     

进贤湖泊水生维管束植物

１９９３年１０月－１９９４年８月对进贤水生植物进行了调查研究。共采集到水生植物３３种,隶属于２１科２５属。其中军山湖平均生物量仅只６８６／ｍ２,水生植物现存量（湿重）、生产力（湿重）和可供鱼产力（湿重）分别为１４６×１０７Ｋｇ、１８２×１０７Ｋｇ和９１５００Ｋｇ。     

反相高效液相色谱法测维生素A含量

目的：建立一种用反相高效波相色谱测定维生素Ａ的方法。方法：色谱柱：Ｈｙｐｅｒｓｉｌ ＯＤＳ（１５０ｍｉｎ×４６ｍｍ），流动相：甲醇－水（９６：４），流速１．０ｍｌ／ｍｉｎ，紫外检测器波长３２５ｎｍ，柱温２５℃，外标法测定。结果：维生素 Ａ在 ２．５～３０．０μｇ／ｍｌ之间有良好的线性关系，最低检测浓度为 １．５μｇ／ｍｌ，平均回收率为９８．５％，精密度ＲＳＤ±ｌ、５６％（ｎ＝３）。结论：本方法准确、灵敏、适应面广。     

暴发性鱼病菌苗产生免疫力的时间及免疫时效研究

嗜水气单胞菌苗免疫接种试验表明，室温３０℃时，试验鱼注射接种１．８～２．７×１０８个／尾的灭活菌苗，８－１０天后即产生较强的免疫力，注射接种１％一１‰的灭活组织苗０．２－０．３ｍｌ／尾，６－８天后即产生较强的免疫力，两者的保护力均达９２％以上，浸泡相当于１．８×１０６个／ｍｌ的脂多糖粗提物（ＬＰＳ），１０—１２天后产生的保护力可达７０％左右。不同温度的接种试验表明，水温３０℃时接种比１５℃时接种，免疫力的形成早４—７天。大池试验表明，灭活苗苗接种鱼的免疫时效达６个月以上。     

有效氯对浮游植物生长的影响

用０．５×１０－６和１．０×１０－６有效氯处理虾池浮游植物，用４．０×１０－６、１００×１０－６和１５０×１０－６有效氯处理叉鞭金藻、球等鞭金藻两个品种（９００２、３０１１）、巴夫藻（３０１２）、塔胞藻和小新月硅藻，结果表明，０．５×１０－６—１．０×１０－６的有效氯对虾池浮游植物产氧有严重抑制，但对叶绿素含量无显著影响；金藻类用１５０×１０－６有效氯处理１．５ｈ仍可存活，但小新月和塔胞藻在有效氯为４．０×１０－６时，短时间即可致死。     

稀土添加剂网箱养鲤试验

采用不同添加量（０，１０７，１２５，１４３，１７０ｍｇ／ｋｇ饲料）的维西稀氧化物作添加剂，在５只５ｍ×５ｍ×３．５ｍ的网箱中进行养鲤试验。除添加量不同外，配合饲料其它成分完全一样，鲤入箱规格基本一致。结果表明投喂添加稀土的配合饲料，鲤增重倍数为９．７－１０．８，净产量１１９．４－１３２．８ｋｇ／ｍ＾２，对照网箱增产１２．３％－２５％，稀土添加剂投入产出比为１：３７。本文认为稀土添加量以１４３ｍ．．     

草鱼出血病细胞培养灭活疫苗旋转瓶法大规模生产工艺↑（*）

Ｃａｒｅｌ氏瓶静置培养草鱼ＣＩＫ细胞，细胞２～３ｄ内长成单层，细胞单层均匀而稳定；旋转瓶培养，细胞７ｄ左右长成单层，细胞单层面积大，病毒培养产量高。２种方式所培养病毒的ＴＣＩＤ５０／ｍｌ值稳定在６．０左右。０．１％福尔马林４℃条件下灭活病毒材料１７ｄ制备疫苗，疫苗性能稳定，安全性好。疫苗效力检验结果表明，注射免疫１０ｄ和浸泡免疫１０ｄ后，免疫鱼体内血清中和抗体效价分别为１０７．９±１１．０（３）和６８．５±９．９（３），免疫保护力分别为（７７．１±８．９）％（３）和（７３．９±８．３）％（３），与对照组相比差异显著。本研究建立了草鱼细胞培养灭活疫苗大规模生产工艺流程，进行了较大规模的疫苗生产和生产性免疫试验，免疫草鱼成活率平均达到８５％以上。     

三种鲤对暴发性鱼病抗病力的差异

本文报道三种鲤对嗜水气单胞菌引起暴发性鱼病的抗病力试验结果。当菌液浓度为６．０×１０￣８ＣＦＵ／ｍｌ，采用１０￣０、１０￣（－１）、１０￣（－２）、１０￣（－３）四个稀释度、０．３ｍｌ／尾注射剂量时，建鲤、野鲤和镜鲤的半数致死量（ＬＤ＿（５０））分别为１０￣（－１．３７５）、１０￣（－０．９７６）、１０￣（－０．５６２）。这三种鲤的半数致死量差异显著（Ｆ＞Ｆ＿（０．０５））。从四个方面研究了抗病机理：白细胞吞噬功能和补体替代途径（Ｃ＿３旁路）杀菌能力，镜鲤较强于野鲤和建鲤，但无显著差异（Ｆ＜Ｆ０．０５）；红细胞Ｃ＿（３ｂ）受体花环率和补体总量（单位／ｍｌ），是建鲤＞野鲤＞镜鲤，差异极显著（Ｆ＞Ｆ０．０１）。本研究结果还表明建鲤的红细胞Ｃ＿（３ｂ）受体花环率和补体总量稍高，但对暴发性鱼病病原（嗜水气单胞菌）较易感染。以上结果证明，不同品系鲤鱼对暴发性鱼病有种内特异性。     

二氧化氯改善养殖水环境效果的研究

使用二氧化氯化处理水养殖用水（实验室规模）测定水化学指标及水中细菌数量的变动，结果表明：（１）二氧化氯能够明显中水环境的溶氧（增氧量为５．８－２２．７％）减低水中ＣＯＤ和ＮＨ３－Ｎ值（ＣＯＤ降低幅度为２６．０－５８．８％，ＮＨ３－Ｎ清除率为１９．４－３８．５％）（２）二氧化氯浓度为０．２×１０＾－３ｍｏｌ／ｍ＾３及１．２×１０＾－３ｍｏｌ／ｍ＾３可有显降低海水中弧菌数及细菌总数，随着药物浓度增大，     

Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean

The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.     

Growth performance,digestive enzyme activity and immune response of Japanese sea bass,Lateolabrax japonicus fed with fructooligosaccharide

In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.     

Involvement of gonadal steroids in final oocyte maturation of white perch (Morone americana) and white bass (M. chrysops): in vivo and in vitro studies

Plasma estradiol-17 (E₂), testosterone (T), 17,20-dihydroxy-4-pregnen-3-one (DHP) and 17,20,21-tri-hydroxy-4-pregnen-3-one (20-S) levels were measured by radioimmunoassay (RIA) in white perch (Morone americana) and white bass (M. chrysops) that were induced to undergo final oocyte maturation (FOM) with human chorionic gonadotropin (hCG). Plasma DHP levels increased in females of both species in association with oocyte germinal vesicle migration (GVM) and germinal vesicle breakdown (GVBD) and decreased thereafter. Plasma 20-S levels also increased with oocyte GVM in white bass, but were several-fold lower than DHP levels. Circulating E₂ and T levels were greatest during GVM and GVBD in both species and decreased to low levels during oocyte hydration and ovulation. Follicles from white perch and white bass which received a priming injection of hCG in vivo, produced both DHP and 20-S in vitro after exposure to hCG and their oocytes underwent GVBD. Ovarian incubates from unprimed fish of either species produced only E₂ and T and their oocytes did not complete GVBD. Oocytes from unprimed bass, but not perch, matured when follicles were exposed to hCG in vitro. Both trilostane and cycloheximide blocked in vitro production of DHP and 20-S and oocyte GVBD by white perch follices. DHP and 20-S were equipotent inducers of FOM in the GVBD bioassay. None of several other structurally-related steroids tested were effective within a physiological range of concentrations. These results indicate a role for DHP and 20-S in the control of FOM in white perch and white bass.     

Cardiac,ventilatory and metabolic responses of two ecologically dissimilar species of fish to waterborne cyanide

Changes in heart rate, ventilatory activity and oxygen consumption were determined in trout (Salmo gairdneri) and brown bullhead catfish (Ictalurus nebulosus) during exposure to a steadily increasing concentration of waterborne cyanide selected to produce death in 8–9 hours for each species. The lethal cyanide concentration for the bullheads was an order of magnitude higher than for trout. Trout developed an immediate and gradually increasing bradycardia throughout the exposure period. Cyanide produced tachycardia in the bullhead followed by a gradual onset of bradycardia as the concentration of cyanide was raised. Pericardial injection of atropine (a muscarinic cholinergic antagonist) indicated that bradycardia in the trout was due initially to increased vagal tone but later due to the direct effect of cyanide on the heart. Hyperventilation in the trout persisted throughout the exposure period, although the rate and amplitude fluctuated and was variable between individual fish. During the last hour of exposure (highest cyanide concentration), ventilation was characterized by rapid, shallow breaths followed by a sudden respiratory arrest. The bullheads exhibited hyperventilation during the first 3 hours of exposure followed by a gradual, linear drop in ventilation rate and amplitude until death occurred. Cardiac and ventilatory responses in both species were attributed to stimulation of central and peripheral chemoreceptors by cyanide. Evidence is presented which suggests the initial response in the bullheads was due, at least in part, to gustatory stimulation by the cyanide. Oxygen consumption of the trout remained above pre-exposure levels for the majority of the test period. Oxygen consumption in the bullhead paralleled the changes in heart and ventilatory rates. Whole-body lactate levels of fingerlings of both species during cyanide exposure were measured to estimate the extent of anaerobiosis. Whole-body lactate levels were much greater in the bullheads than the trout, indicating a higher capacity for anaerobiosis, possibly due to a greater fuel supply. Overall, the trout responded to cyanide in a manner similar to that produced by environmental hypoxia whereas the bullheads experienced a gustatory stimulus which masked the hypoxia-like response.     

An overview of stress physiology of fish transport: changes in water quality as a function of transport duration

This study brings an integrated analysis about the relationship between water deterioration and its physiological consequences in live fish transport. The analysis was focused on the transport water and its deterioration, and physiological challenges imposed on the fish. Usual commercial handling procedures employed to mitigate fish stress during transport were discussed. Future topics of research for the establishment of safer fish transport protocols were proposed. Transport was classified into short (≤8 h) or long transport (>8 h). The main issue in short transports should be the prevention of water pH reduction, while in long transports it is the increase in ammonia. Plasma cortisol is the most employed marker for stress and is acutely elevated upon short episodes of transport, but remains elevated even in long‐transport events. Plasma glucose is perhaps a better marker for handling stress. Plasma lactate, pH, osmolality CO₂ and ions should be more often evaluated. Plasma Na⁺ and Cl^‐ are very useful markers of acidosis, due to their respective exchange for H⁺ and , for acid–base regulation. The establishment of species‐specific transport protocols should be preceded by such combined analyses of water and physiological parameters.     

Are hatchery‐reared abalone naïve of predators? Comparing the behaviours of wild and hatchery‐reared northern abalone,Haliotis kamtschatkana (Jonas, 1845)

Abalone populations have declined worldwide, generating interest in enhancement using hatchery‐reared individuals. In many cases, such restoration efforts have met with limited success due to high predator‐induced mortality rates. Furthermore, the mortality rates of outplanted hatchery abalone are often considerably higher than for wild individuals. This study uses northern abalone (Haliotis kamtschatkana) as a case study to determine whether hatchery‐reared abalone behave differently than their wild counterparts. In the field, outplanted hatchery‐reared abalone were significantly less responsive than wild abalone, in terms of number of abalone responding and intensity of response, to nearby movement and to physical contact with an inert probe. Also, when encountering a cue to which all abalone responded (a seastar predator), hatchery‐reared individuals remained subdued. Anti‐predator behavioural deficits in hatchery‐reared abalone were more pronounced in 4‐year‐old individuals than in 1‐year‐old individuals, suggesting an influence of either age or amount of time spent in the hatchery environment. These behavioural differences are expected to increase the vulnerability of hatchery‐reared abalone to predators, and are likely a major cause of their elevated predator‐induced mortality when outplanted.     

Effects of cadmium on the kinetics of calcium uptake in developing tilapia larvae, Oreochromis mossambicus

The toxic effects of Cd²⁺ on Ca²⁺ influx kinetics in developing tilapia (Oreochromis mossambicus) larvae were evaluated. Addition of 20 µg l^-1 of Cd²⁺ to the environment of 0 and 3 day-old larvae competitively inhibited the Ca²⁺ uptake within 4h resulting in a great increase in K_m values for Ca²⁺ influx (19.3 and 17.4 fold, respectively) as compared with their respective controls. Consequently, the actual Ca²⁺ influx of larvae in solutions of 0.2 mM Ca²⁺ are suppressed by 32–45%. Also, 3 day-old larvae were more sensitive to internally accumulated Cd²⁺ than 0 day-old larvae. Although the Ca²⁺ influx in 0 and 3 day-old larvae may be restored to the levels of their respective controls with 24h of being transferred to a 20 µg l^-1 Cd²⁺ solution, total body Ca²⁺ content was significantly reduced in 3 day-old larvae. Increased Ca²⁺ uptake efficiency ensures sufficient Ca²⁺ for normal growth. However, rapid increase in Ca²⁺ influx after hatching also leads to higher Cd²⁺ uptake. Exposure to Cd²⁺ will lead to a drop in body Ca²⁺ content resulting in retardation of larval growth. Therefore, we conclude that if Ca²⁺ uptake is interfered with at this critical stage of development, larvae will not be able to maintain normal levels of body Ca²⁺ and will show signs of Cd²⁺ poisoning.     

Migratory dynamics of stream-spawning longnose gar (Lepisosteus osseus)

Abstract– Literature evidence suggests that lake-dwelling longnose gar (Lepisosteus osseus) enter tributary streams to spawn, Until the present study, the dynamics of this breeding migration had never been investigated quantitatively. During the summers of 1991 and 1992, longnose gar were captured as they entered Weaubleau Creek, Missouri, a tributary of Harry S. Truman Reservoir. The in-stream spawning migration began in early April and ended in late May, and was positively correlated with stream flow and water level, and negatively correlated with water temperature. In-stream residence times ranged from 15 to 94 days, with males exhibiting longer residence times than females. Once in-stream, longnose gar travelled as far as 10 km upstream and occupied certain pools at greater relative frequencies. Although the reason for this preferential utilization is not completely understood, it may relate to pool depth and riffle proximity. Longnose gar disperse from the spawning stream great distances, with gar captured in Weaubleau Creek being recaptured up to 48 km away. This information should provide fisheries biologists the means to consider the reproductive ecology of this species in their conservation and management decisions.     

Nutritional regulation of hepatocyte fatty acid desaturation and polyunsaturated fatty acid composition in zebrafish (Danio rerio) and tilapia (Oreochromis niloticus)

The desaturation and elongation of [1-¹⁴C]18:3n-3 was investigated in hepatocytes of the tropical warm freshwater species, zebrafish (Danio rerio) and Nile tilapia (Oreochromis niloticus). The hepatocyte fatty acid desaturation/elongation pathway was assayed before and after the fish were fed two experimental diets, a control diet containing fish oil (FO) and a diet containing vegetable oil (VO; a blend of olive, linseed and high oleic acid sunflower oils) for 10 weeks. The VO diet was formulated to provide 1% each of 18:2n-6 and 18:3n-3, and so satisfy the possible EFA requirements of zebrafish and tilapia. At the end of the dietary trial, the lipid and fatty acid composition was determined in whole zebrafish, and liver, white muscle and brain of tilapia. Both zebrafish and tilapia expressed a hepatocyte fatty acid desaturation/elongation pattern consistent with them being freshwater and planktonivorous fish. The data also showed that hepatic fatty acid desaturation/elongation was nutritionally regulated with the activities being higher in fish fed the VO diet compared to fish fed the FO diet. In zebrafish, the main effect of the VO diet was increased fatty acid Δ6 desaturase activity resulting in the production of significantly more 18:4n-3 compared to fish fed the FO diet. In tilapia, all activities in the pathway were greater in fish fed the VO diet resulting in increased amounts of all fatty acids in the pathway, but primarily eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3). However, the fatty acid compositional data indicated that despite increased activity, desaturation of 18:3n-3 was insufficient to maintain tissue proportions of EPA and DHA in fish fed the VO diet at the same level as in fish fed the FO diet. Practically, these results indicate that manipulation of tilapia diets in commercial culture in response to the declining global fish oil market would have important consequences for fish fatty acid composition and the health of consumers. Scientifically, zebrafish and tilapia, both the subject of active genome mapping projects, could be useful models for studies of lipid and fatty acid metabolism at a molecular biological and genetic level. This revised version was published online in August 2006 with corrections to the Cover Date.     

Production of diatom–bacteria biofilm isolated from Seriola lalandi cultures for aquaculture application

Controlled incorporation of selected microalgae and bacteria in aquaculture systems can be beneficial because they can act as microbiological control. That is why the characteristics of biofilm generated naturally in Seriola lalandi culture cages were analysed, their potential benefit to the growth of larvae was studied, and their controlled use for improving the larval viability and as a vector to improve incorporation of previously studied probiotic bacteria was tested. According to biodiversity results, these biofilms are composed of a diatom–bacteria mix showing a decrease in biodiversity in laboratory culture conditions being dominated by Navicula phyllepta and bacteria of the family Rhodobacteraceae. This can be produced on mesh substrates incorporated in bioreactors with rapid growth rate and adhesiveness. Preliminary results from the addition of substrates with this specific biofilm in larvae culture systems showed that it is consumed by the larvae without negative effects, while positive effects on the viability of larvae in combination with probiotics were observed. Considering preliminary results, the addition of these specific substrates with diatom–bacteria biofilms could be a good improvement for aquaculture systems and together with the use of probiotics can contribute to maintaining a stable and controlled system improving the viability of the larval fish culture in its early stages.