皱纹盘鲍工厂化育苗技术

利用坑道培育和海捕的皱纹盘鲍亲体，进行人工催产、授精；以高密度集中培育浮游幼虫；用以舟形藻、卵形藻和菱形藻为主的底栖硅藻作为开口饵料，进行稚鲍前期培育；以幼鲍专用饲料作稚鲍后期饵料，进行稚鲍后期流水平面培育。1996年在8m2的采苗水面培育出壳长1．0～1．2cm的稚鲍2．4万个；1997年在50m2的采苗水面培育出壳长1．0～1．7cm的幼鲍16万个。     

安特消毒剂在皱纹盘鲍稚鲍培育中的应用

在皱纹盘鲍工厂化育苗生产中，稚鲍剥离后大量死亡，育成率低下，是困扰生产单位的一大难题。我们１９９５年和１９９６年在稚鲍培育中，采用安特消毒剂处理稚鲍和培养用水，取得了明显的效果，现报告如下：１材料与方法１．１试验在长岛县第一育苗场进行，稚鲍剥离后在规格为 ９ ｍ×０． ９ ｍ×． ５ ｍ和 １．０ ｍ×． ０ ｍ×０．９ ｍ的培育池中流水充气培养。所用海水经砂滤处理，海水盐度３１．２～３１．８，ｐＨ８．２～８．４。稚鲍主要投喂人工配合饵料，一般傍晚投喂，每天上午７：００～８：００清除残饵。１．２安特消毒剂…     

几种免疫因子对九孔稚鲍免疫力的影响

选用浓度分别为5×10^-6、10×10^-6、0．5×10^-6、1×10^-6的维生素B6（维生素类）、益母草膏（中草药类）、腐殖酸（天然螯和剂）和大蒜素（免疫药物）4种制剂，采用浸浴的方法，对11-39日龄的九孔稚鲍（Haliotis diversicolor supertexta）进行免疫刺激。试验期间每两天换水、补药一次，以维持各组原有的药物浓度，同时对稚鲍的脱板情况进行计数；最后取样测定各组幼体酚氧化物酶、溶菌酶的活性。试验结果表明。各药物组的酚氧化物酶和溶菌酶含量均显著高于对照组（p〈0．05），且稚鲍成活率亦有显著性提高。试验结束时大蒜素组的成活率最高，可达60．00±3．33％；其次为益母草膏、腐殖酸和维生素B6组，成活率分别为56．60±1．66％、45．05±2．44％和42．67±3．13％；均极显著高于对照组的8．59±7．14％（0〈0．01）。由此可见，增强机体的抗氧化能力可提高稚鲍的成活率；本试验所选用的4种免疫因子均可提高九孔稚鲍的免疫力．能有效地提高鲍鱼的附板率。     

皱纹盘鲍稚鲍剥离后大量死亡原因研究

针对稚鲍剥离后大量死亡问题，进行稚鲍剥离规格、稚鲍剥离后直接投喂人工合成饵料与继续摄食底栖硅藻的对比试验，结果是：4mm稚鲍剥离死亡率比2mm稚鲍剥离死亡率低得多，稚鲍剥离后投喂人工合成饵料死亡率很高，摄食底栖硅藻，死亡率则很低。     

关于玛瑙鲍的探索与研究

选择皱纹盘鲍（Ｈａｌｉｏｔｉｓ ｄｉｓｃｕｓ ｈａｎｎａｉ）的变异个体－－贝壳为红色的玛瑙鲍（Ａｇａｔｅ Ａｂａｌｏｎｅ）作亲体，进行人工繁殖的培育。发现在性产物排放诱导率、孵化率、幼虫附着率和稚鲍生长等方面，玛瑙鲍与皱纹盘鲍大致相同。但稚鲍对不良环境（如赤潮）的抗性，玛瑙鲍明显强于皱纹盘鲍，３２ｄ存活率，前者为６３．１％，后者为３４．３％。ＬＤＨ电泳图谱显示，玛瑙鲍内脏组织中ＬＤＨ活性较高，而被     

九孔鲍人工育苗技术探讨

采用阴干加紫外线处理海水催产的方法，进行九孔鲍室内人工育苗研究，使用雌亲鲍1343粒，平均规格5．7cm，雄亲鲍117粒，平均规格5．8cm，共获得受精卵9500万粒，受精率91．5％，以塑料薄膜作为附着基质，共附着匍匐幼体607万粒。经过64～73d的附着期间的管理，剥离0．21～1．0cm稚鲍347万粒，成活率达57．2％，又经过98～102d的培育，获得规格1．0～2．5cm的鲍苗121．5万粒，平均成活率达35．0％。     

关于抑制稚鲍壳质腐蚀方法研究

若在循环过滤海水中长期持续培育稚鲍，则屡屡发生壳顶至中部的壳面遭到腐蚀而珍珠质层裸露现象。在处于同一培育环境时，呈现这种腐蚀状态的稚鲍，出现率往往几乎高达百分之百。与在其它培育环境中养殖的未腐蚀的健壮稚鲍相比，这种珍珠质层裸露的稚鲍，壳的腐蚀部分变薄，用指尖只轻轻一按就很容易玉碎。另外，这样的稚鲍多发育不良。对大批培育苗种来说，这一点尤其值得注意。     

皱纹盘鲍稚鲍的酒精麻醉剥离试验

皱纹盘鲍(Haliotis discus hannai Ino)稚鲍的剥离，是的人工育苗工艺中不可缺少的作业环节。关于稚鲍的剥离方法，国外曾有过一些报道，如日本，用氨基甲酸乙酯或对氨基苯甲酸乙酯等药物麻醉剥离已成为近年来较普遍应用的剥离方法。对10毫米以上的稚鲍用温水剥离有时也作为一种有效的实用方法之一。     

皱纹盘鲍稚鲍对海水酸化与溴氰菊酯复合胁迫的响应

为探究海水酸化与溴氰菊酯(DM)复合暴露对皱纹盘鲍(Haliotis discus hannai)稚鲍的毒性效应,采用3个pH(pH 8.1、pH 7.7和pH 7.4)和3个溴氰菊酯浓度(0、0.6和6 μg/L)对稚鲍进行复合胁迫,并对贝壳微观结构与硬度、组织中抗氧化酶活性以及应激、凋亡相关基因表达量进行了检测。结果显示,经过海水酸化与溴氰菊酯复合暴露31 d后稚鲍贝壳CaCO3晶体沉积困难,文石板片变小并形成分散的板层堆叠,文石板片之间孔隙增大,并且伴随着贝壳硬度的显著降低。同时,海水酸化与溴氰菊酯能够引起皱纹盘鲍稚鲍组织抗氧化酶活力的改变,其中稚鲍超氧化物歧化酶(SOD)活力随着pCO2与溴氰菊酯浓度的上升而持续降低,并且在海水酸化与溴氰菊酯复合暴露下稚鲍SOD活力明显低于单一暴露物,说明海水酸化与溴氰菊酯对稚鲍SOD活力的影响具有明显交互作用。而在相同pH暴露下,溴氰菊酯能够使稚鲍CAT与GST活力显著上升。此外,本研究还观察到了稚鲍组织中应激基因与凋亡相关基因表达量随着pCO2与溴氰菊酯浓度的上升均有提高,并且海水酸化与溴氰菊酯暴露在HSP70、HSP90、Caspase-3以及FADD等基因表达量上具有明显协同作用。综上所述,海水酸化与溴氰菊酯暴露能够对稚鲍产生明显毒害效应,并且在引起稚鲍组织氧化应激与细胞凋亡的反应中具有一定交互作用。     

稚鲍网箱饲育期给水量的探讨

稚鲍在网箱饲育期间给水量的多少，是直接关系到饲育水质能否保持正常、稚鲍的生长能否受到影响的重要工艺指标之一。给水量不足，将可能导致饲育水质的逐步恶化，稚鲍的摄食与生长将因此而受到影响，给水量增大，又将要提高对供水设施的要求，增加水电消耗。     

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.