大港湾海域水产生物体内Cu,Zn和石油类的分析与评价

本文根据１９９７年７月福建省惠安县大港湾海域水产生物体内污染物的检测资料，０初步分析了大港湾海域的鱼类，甲壳类及贝类体内Ｃｕ，Ｚｎ和石油类的含量水平。其中在鱼体内Ｃｕ，Ｚｎ和石油类的平均含量分别为０．７６，５．０２，０．９３ｍｇ．ｋｇ＾－１，在甲壳类体内，Ｃｕ，Ｚｎ和石油类的平均含量分别为３．０５，１３．９２，５．５ｍｇ．ｋｇ＾－１。在贝类体内，Ｃｕ，Ｚｎ和石油类的平均含量分别为２．６１，１５．６     

氨基酸络合盐添加剂用于罗非鱼养殖试验

利用氨基酸络合盐添加剂进行罗非鱼高密度流水养殖试验，干池验收表明：与对照组相比，日增重率提高３６．７％，饵料效率提高３１．７％，成活率提高９．２％，每增重１ｋｇ鱼的饵料成本下降２４．３％。试验组鱼肉中Ｃｕ，Ｆｅ，Ｚｎ，Ｍｎ含量明显高于对照组。     

饵料中不同脂肪源对团头鲂幼鱼生长及组成的影响

团头鲂幼鱼在摄食添加不同脂肪源脂质的饵料饲养4周后，脂质添加组团头鲂体重增加快，与对照组比均有显差异；试验组鲢鱼油添加组和大豆油添加组的鱼体增重速度快，相对增重率分别为113．9％、117．9％，饵料系数分别为2．43、2．24。鲱鱼油添加组及对照组的相对增重率分别为98．1％、85．1％：饵料系数分别为2．84、2．95。鲢鱼油添加组鱼体脂质作用最好；大豆油添加组鱼体背部肌肉脂质积累较好；而鲱鱼油添加组有内脏脂质积累的表现。这说明，改变饵料的脂肪源及提高饵料中脂质含量可影响团头鲂幼鱼的生长和组成，鲢鱼油是优良的团头鲂饵料脂肪源。     

尼罗罗非鱼幼鱼饵料锌的需求量

尼罗罗非鱼幼鱼在７０ｄ中投喂具有和没有补充锌的饵料，其锌含量范围为０～１００ｍｇＺｎ／ｋｇ饵料。投喂含有１ｍｇＺｎ／ｋｇ基础饵料的尼罗罗非鱼发育不佳，如厌氧和生长差。投喂补充锌最低含量（０和５ｍｇＺｎ／ｋｇ饵料）饵料具有最差的生长和最高的死亡率，而过３０ｍｇ／ｋｇ含量则表明死亡率减少和明显地改进了生长。饵料锌水平与全身锌浓度有显著相关，也观察到饵料锌和全身铁浓度有强烈的负相关。其增重百分数，饵料效     

黑鲷幼鱼对饵料蛋白质,脂肪,糖类需求量的研究

实验了９种人工配合饵料，其中，蛋白质，脂肪和糖类含量为４１．２％，１７．６％和１５．９％的４号饵料，使黑鲷幼鱼生长最快，实验４３天，幼鱼增重率为６４．３％，饵料系数为１．３。     

3种重金属离子和2种杀虫剂对梭鲈胚胎发育的影响

在常温静水条件下，研究了铜（Ｃｕ）、锌（Ｚｎ）、镉（Ｃｄ）３种重金属离子和甲醛、晶体敌百虫２种杀虫剂对梭鲈（Ｓｔｉｚｏｓｔｅｄｉｏｎｌｕｃｉｏｐｅｒｃａ）胚胎发育的影响。结果表明，３种重金属离子对梭鲈胚胎的毒性大小依次为：Ｃｄ２＋ ＞Ｃｕ２＋ ＞Ｚｎ２＋；当甲醛浓度为１０００ｍｇ／Ｌ时，对梭鲈胚胎的毒性影响较强，而高浓度的晶体敌百虫对梭鲈胚胎有明显的毒性作用。在梭鲈繁殖用水中使用杀虫剂时，甲醛和晶体敌百虫的安全浓度分别为２００ｍｇ／Ｌ和０．４ｍｇ／Ｌ。     

鲈鱼对浮性配合饵料中镉的积累

试验研究了浮性配合饵料置于镉（Ｃｄ）污染的海水后，吸附Ｃｄ的能力及鲈鱼摄食及Ｃｄ污染的配合饵料后，Ｃｄ在鱼体内的积累情况，结果表明，配合饵料置于海水中６０ｍｉｎ后吸附在饵料中的Ｃｄ，要比水中Ｃｄ的浓度高出数十倍，当配合饵料Ｃｄ含量为３ｍｇ／ｋｇ（干重）经４２ｄ的喂养，鲈鱼肌肉和肝脏中的Ｃｄ含量分别可达１２７和０．２６５ｍｇ／ｋｇ（湿重），最大富集系数分别为０．１９６和０．３２３，当配合饵料中Ｃｄ含     

铜锌离子对褶皱臂尾轮虫的急性毒性试验

研究了Ｃｕ＋＋、Ｚｎ＋＋对褶皱臂尾轮虫（Ｂｒａｃｈｉｏｎｕｓｐｌｉｃａｔｉｌｉｓ）的急性毒性影响。实验温度２５±１℃,轮虫对Ｃｕ＋＋的污染相当敏感,Ｃｕ＋＋２４ｈ半致死浓度为２４ｈＬＣ５０＝１４．４７μｇ／Ｌ～２１．９３μｇ／Ｌ;Ｚｎ＋＋２４ｈ半致死浓度为２４ｈＬＣ５０＝３．４０４ｍｇ／Ｌ～４．５４９ｍｇ／Ｌ。     

工厂化养鳖饲料中维生素E的应用研究（下）

－试验结果（１）生长比较饲养试验中,每两周各组进行一次生长测定,期间幼鳖生长测定五次,生长情况见表２、对照组和试验组各生长指标的比较结果见表３。表２幼鳖生长结果表３生长结果比较表３显示,添加５０ｍｇ／ｋｇ的Ａ组和１５０ｍｇ／ｋｇ的Ｂ组,饵料系数比对照Ｃ组分别低０－１５０和０．４４６,饵料效率比Ｃ组分别高２－４％和１０－９％。同时Ｂ组和Ａ组相比,Ｂ组饵料系数低０－２９６,饵料效率高８－５％。这说明增加维生素Ｅ的添加量有利于提高饵料的利用率、降低饵料系数。显示饲料中维生素Ｅ添加水平为５０ｍｇ／ｋｇ和…     

添加稀土元素的配合饲料对中国对虾生长效果的研究

本文讨论了添加稀土元素的配合饲料对中国对虾（Ｐｅｎａｅｕｓｃｈｉｎｅｎｓｉｓ）生长效果的影响，从试验中得到了以下结论。（１）添加稀土元素的配合饲料对其有促生长作用，其适宜添加量为３０～１００ｍｇ／ｋｇ，其中以添加６０ｍｇ／ｋｇ为最适宜，该组增长比为１３５，增重比为１５０（对照组为１００）。（２）成活率有不同，但差别不明显，说明稀土元素对其成活率无明显影响。（３）用添加６０ｍｇ／ｋｇ稀土元素的饲料在     

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.     

Protein and amino acid composition from the mantle of juvenile O ctopus vulgaris exposed to prolonged starvation

Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg^?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg^?1 protein) than essential amino acids (425.82 ± 9.15 g kg^?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting.     

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.