关于新对虾属Metapenaeus幼体发育分期的探讨

新对虾属Ｍｅｔａｐｅｎａｅｕｓ为对虾科Ｐｅｎａｉｄａｅ中的重要类群，随着养虾业的发展，新对虾越来越受到重视。在人工育苗中，虾类幼体发育分期对指导生产有现实意义。国外学者Ｍ．Ｓ．Ｍｕｔｈｕ等（１９７８）对近缘新对虾和道氏新对虾的糠虾（Ｍｙｓｉｓ）阶段分为５期，并在第Ⅴ期糠虾幼体之后增加两个中间期，形成Ｎ－Ｚ－Ｍ－Ｉ的“６－３－５－２”模式。作者在中型新对虾的幼体变态实验观察中注意到，糠虾幼体在一次蜕皮后其体长和附肢形态均有渐微的变化，这种形态上的细微差异不宜作为分期的依据，幼体分期的主要依据以蜕皮为标志。因此新对虾属的幼体发育分期可借鉴中国对虾（Ｐｎｕａｅｕｓｏｒｉｅｎｔａｌｉｓ）幼体分期模式划分，即Ｎ－Ｚ－Ｍ为“６－３－３”。     

中国对虾（Penaeus orientalis Kishinouye）的几种必需脂肪酸营养价值的比较研究

用四种试验饵料，其中分别含有１％高纯度的ω－３及ω－６不饱和脂肪酸（亚油酸Ｃ１８∶２ω６、亚麻酸Ｃ１８∶３ω３、花生四烯酸Ｃ２０∶４ω６、二十二碳六烯酸Ｃ２２∶６ω，ＤＨＡ）以及一种对照饵料含有５％棕榈酸Ｃ１６∶０和油酸Ｃ１８∶１ω９混合物对中国对虾（ＰｅｎａｅｕｓｏｒｉｅｎｔａｌｉｓＫｉｓｈｉｎｏｕｙｅ）幼虾进行了为期３２天的投喂试验，从成活率、蜕皮次数及增重等实验结果可见二十二碳六烯酸（ＤＨＡ）对中国对虾幼虾具有最高的营养价值。同时，对海捕和人工养殖的中国对虾的脂肪酸组成进行了比较，两者都含有大量的ω－３系列的高度不饱和脂肪酸；但是与海捕虾相比较，人工养殖对虾的ＤＨＡ含量较低，而亚油酸含量较高。上列结果表明在对虾饵料中补充富含ＤＨＡ的脂肪源将有效地促进对虾增产。     

pH和盐度对斑节对虾存活,生长和渗透调节能力的影响

斑节对虾幼虾（平均体重４．２－５．５ｇ）的ｐＨ低临界值使用盐酸醋化海水的静态生物测定的方法来求得。在盐度３２ｐｐｔ进其致死ｐＨ（即９６ｈＬＣ５０的ｐＨ）为３．７（９５％置信度是３．４和４．１）。最小可采用的ｐＨ（此ｐＨ在２３ｄ中使生长减少５％），在盐度为３０ｐｐｔ时估算为５．９。同ｐＨ７．８相比较，长期（２３ｄ）置于低ｐＨ（４．９），盐度为３０ｐｐｔ时，对虾于民分明显减少（Ｐ＜０．００１），而蜕皮     

对虾池不同综合养殖系统效率和效益的比较研究

利用５０个５．０×５．０×１．８ｍ陆基围隔研究了中国对虾与台湾红罗非鱼、海湾扇贝和缢蛏投饵或施肥混养及鲈鱼与中国对虾和台湾红罗非鱼混养最佳结构的生态效率、生产效果和经济效益。结果表明,几种综合养殖系统最佳结构下各种养殖对象对Ｎ的绝对利用率由高至低依次为：鲈鱼－对虾－罗非鱼（３０．９１％）＞对虾－海湾扇贝（２１．０９％）＞对虾－罗非鱼施肥混养（２０．１２％）＞对虾－罗非鱼投饵混养（１７．８１％）＞对虾－缢蛏（１６．９３％）＞单养对虾（１１．５２％）;对Ｐ的绝对利用率由高至低依次为：对虾－缢蛏（１６．０８％）＞鲈鱼－对虾－罗非鱼（１２．８３％）＞对虾－罗非鱼投饵混养（１２．６３％）＞单养对虾（１０．８８％）＞对虾－海湾扇贝（６．０１％）＞对虾－罗非鱼施肥混养（４．０４％）;其产出投入比由高至低依次为：对虾－罗非鱼投饵混养（１．９９）＞对虾－罗非鱼施肥混养（１．９８）＞对虾－海湾扇贝（１．５３）＞单养对虾（１．３８）＞鲈鱼－对虾－罗非鱼（１．３０）＞对虾－缢蛏（１．２３）。     

饲料中必需脂肪酸对中国对虾体内必需脂肪酸含量的影响

用正交设计法设计亚油酸（１８∶２ｎ－６）、亚麻酸（１８∶３ｎ－３）、二十碳五烯酸（２０∶５ｎ－３）和二十二碳六烯酸（２２∶６ｎ－３）３因素、３水平饲喂中国对虾试验,结果表明,对虾体内４种必需脂肪酸（ＥＦＡ）含量随饲料中４种必需脂肪酸含量增加而增加。当饲料中亚麻酸、二十碳五烯酸和二十二碳六烯酸含量分别为０．８４％～１．１０％、０．２１％～０．４８％和０．３７％～０７４％时,养殖对虾与野生虾体内这３种必需脂肪酸含量接近。由于饲料中亚油酸含量较高,所以养殖虾体内亚油酸含量高于野生虾。     

江蓠与新对虾、青蟹混养试验

细基江蓠繁枝变种与新对虾，青蟹混养试验结果表明：（１）细基江蓠繁枝变种生长的最适温，盐度分别为１７－３０℃和１７－２９‰，这一温，盐度范围也适合新对虾和青蟹的生长；鱼塘海水的温，盐度变化与沿海不同，因此，移植野生江蓠到鱼塘养殖时要考虑这一特点。（２）江蓠在不同的生长季节的最适生长水层是不同的。（３）江蓠的主要有效氮是ＮＨ４＾＋，而新对虾，青蟹的排泄物可分解出大量的ＮＨ４＾＋。这样，江蓠与新对虾，青     

－18℃冷冻条件下中国对虾肌细胞线粒体超微结构的变化

通过对冷冻（－１８℃）条件下保存４００ｄ的中国对虾肌细胞线粒体超微结构变化的透射电镜观察，结果表明：内嵴肿胀，外膜破裂、溶解，线粒体变形膨胀，严重者解体，其中外膜破坏快于内嵴。肌细胞线粒体的变化可分为３个时期（初冻期、稳定期和解体期）。     

菲律宾蛤仔（Ruditapes philippinarum）低温保活方法的研究↑（*）

本文在菲律宾蛤仔（Ｒｕｄｉｔａｐｅｓ ｐｈｉｌｉｐｐｉｎａｒｕｍ）生物学研究基础上，对菲律宾蛤仔在 ２７． ０～－１． ７℃范围内不同温度条件下的存活率，失重率及保活过程中的化学变化等进行了系统的分析研究，确定了菲律宾蛤仔的保活工艺和方法。结果表明，（１）菲律宾蛤仔的最肥季节为每年的 ３～ ７月，出肉率（干物计）最高可达 １０％；（２）最低保活温度为－１．７℃；（３）－１．０～－１．７℃可保活１３天，存活率９１％；（４）－１．０～１．７℃保活，保活时间最长，失重率也低，主要化学成分无显著变化。     

Experimental studies on intensive polyculture of Chinese shrimp with bay scallop

用放在海水池塘中的８个陆基围隔（５０ｍ×５０ｍ×１８ｍ），研究中国对虾（Ｐｅｎａｅｕｓｃｈｉｎｅｎｓｉｓ）与不同密度海湾扇贝（Ａｒｇｏｐｅｃｔｅｎｉｒａｄｉａｎｓ）投饵混养的放养方式、生产力和极限放养量。对虾体长（２８５±０１６）ｃｍ，扇贝壳长（１１０±０１２）ｃｍ，放养密度分别为６０尾／ｍ２和０，１５，４５，７５粒／ｍ２，用投饵和施肥（鸡粪和化肥）饲养。结果表明，扇贝密度为０和１５粒／ｍ２时，对虾的成活率无显著差异。混养（扇贝１５粒／ｍ２）时对虾的出塘体长、体重和产量分别比单养高２５％，３８％和６５％；当扇贝密度高于１５粒／ｍ２时，对虾的平均体长、体重和产量随扇贝密度的增加而显著减少（Ｐ＜００５）。扇贝密度为１５和７５粒／ｍ２时，其产量由４７０ｋｇ／ｈｍ２增至１２３６ｋｇ／ｈｍ２；当扇贝密度高时，去壳后湿重占体重的百分数从（４２８４±３４４）％降至（３７８８±４２６）％。扇贝的极限放养量为６００～８００ｋｇ／ｈｍ２，适宜放养密度为１０～１５粒／ｍ２。     

碳酸盐碱、pH对中国对虾幼虾的致毒效应

实验结果表明，ｐＨ为８．６、９．０、９．３和９．５时，中国对虾（Ｐｅｎａｅｕｓ ｃｈｉｎｅｎｓｉｓ）幼虾２４ｈ半致死碱度（ＬＣ５０）分别为２２．００、１１．６６、６．５７和３．２８ｍｍｏｌ／Ｌ；随着碱度、ｐＨ的升高，中国对虾幼虾的存活率下降。碱度和ｐＨ对幼虾的致毒效应应具综合作用，ｐＨ８。６～９．０时，ＨＣＯ３＾－、ＣＯ３＾２－共同影响幼虾的存活率；ｐＨ９．０～９．５时，ＯＨ＾－协同ＣＯ３＾２－影     

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.