虹鳟、金鳟亲鱼成熟群体卵质比较研究

对相同饲养条件下经产虹鳟和初产金鳟亲鱼自然成熟产卵群体生物学特性及其成熟鱼卵中四种不饱和脂肪酸（亚油酸，亚麻酸，EPA，HDA）组成含量进行分析比较，结果表明：两种鱼成熟产卵期和成熟卵粒重相近；成熟鱼卵四种脂肪酸组成含量（mg/g鲜样）均依次为亚油酸＞DHA＞EPA＞亚麻酸，相关明显（R=0.97)，虹鳟鱼卵四种脂肪酸总和（6．68），必需脂肪酸（3．83），DHA（2．534）含量明显高于金鳟（3．93，2．21，1．14）。金鳟受精卵发眼率较低，可能与鱼卵EFA，DHA含量低有关。     

竞争性酶联免疫法检测水产品中氯霉素

本研究了利用竞争性酶联免疫原理分析测定水产品中氯霉素含量的方法，氯霉素浓度在50～4050ng／Kg范围内呈良好的线性关系，r^2=0．9936。向样品中分别添加0．5μg和2．0μg的氯霉素标准样品，经过检测，其回收率为81．4％～96．2％，相对标准偏差为7．73％和1．97％，结果表明该法筛选检验氯霉素准确精密，重复性好，适合用来检测水产品中的氯霉素。     

俄罗斯鲟鱼卵与西伯利亚鲟鱼卵的营养成分比较

采用生化方法分析了俄罗斯鲟(Acipenser gueldenstaedti)和西伯利亚鲟(Acipenser baerii)鱼卵的营养成分,并对两者的营养品质进行了比较。结果表明:这两种鱼卵的水分含量平均值为62.83%～64.88%,粗蛋白平均含量为20.38%～20.77%,粗脂平均含量为10.41%～13.58%。统计分析表明,俄罗斯鲟鱼卵的粗脂肪含量显著低于西伯利亚鲟鱼卵,而粗蛋白、水分和灰分含量略高于西伯利亚鲟鱼卵。俄罗斯鲟鱼卵和西伯利亚鲟鱼卵的氨基酸组成一致,均含有17种氨基酸,必需氨基酸指数(EAAI)分别为50.66和44.43。两种鲟鱼卵的脂肪酸中,均以C16∶0、C18∶2n6c和DHA为主要脂肪酸,三者总的质量分数达50%左右;而二十碳五烯酸(EPA)与二十二碳六烯酸(DHA)的总量俄罗斯鲟鱼卵高于西伯利亚鲟鱼卵,在两种鱼卵中含量分别为19.47%和16.83%。分析结果表明,两种鲟鱼卵均含有丰富的各种营养成分,但从粗蛋白、必需氨基酸(EAA)、DHA和n3PUFA含量来看,俄罗斯鲟鱼卵的营养价值优于西伯利亚鲟鱼卵。     

咔唑法与间苯三酚法测定硫酸软骨素比较研究

硫酸软骨素（chondroitinsulfate，CS）经水解和显色后，分别采用咔唑法与间苯三酚法测定其质量浓度，并对这2种方法进行比较。结果显示，咔唑法P（CS）和间苯三酚法P（CS）分别在0．01～0．05mg·mL-1和0．1～1．0mg·mL-1范围内与其吸光度值呈良好的线性关系。对同一样品进行6次平行试验，咔唑法的相对标准偏差（RSD）为3．90％，问苯三酚法的RSD为4．28％，均具有较高的精密度。对这2种方法分别进行3个不同加标水平的回收率试验，咔唑法的加标回收率为98．0％～102．5％，间苯三酚法为83．2％～106．6％。因此，咔唑法与间苯三酚法均能准确测定CS的质量浓度。     

分光光度法测定水产品中甲醛含量的研究

研究采用乙酰丙酮分光光度法测定水产品中的甲醛含量，对样品的前处理过程进行了比较系统的探讨，确定了比色测定参数，并对其用于快速测定水产品中甲醛含量的可行性进行了讨论。实验结果表明，用冰浴浸泡法前处理样品时，最佳浸泡时间为10min，样液pH值用100g·L^-1氢氧化钾溶液调至6；沸水浴中最佳显色时间为3min，比色波长为412nm；当甲醛含量在0～2．5μg·mL^-1范围内时，该方法具有很好的线性关系（R^2=0．9998）；与蒸馏法前处理样品相比，该方法的加标回收率比较高，在89．50％～94．25％之间，而前者为64．17％～76．92％；该方法的RSD（％）为2．93％，样品的最低检出浓度为0．9mg·kg^-1。     

牙鲆肌肉中微量元素的测定

以微波消解样品，利用石墨炉法原子吸收光谱法测定了牙鲆肌肉中的铅、镉、砷、硒、铜、铬、锰、镍、钻、锡等十种微量元素的含量。结果表明此方法简便、精密度和灵敏度高。牙鲆肌肉中铬、铜、锰和硒的含量分别可达1．096μg／g、0．613μg／g、0．347μg／g和0．199μg／g，提示牙鲆肌肉中各种有益微量元素含量较高，而有害微量元素砷、铅、镉等的含量均较低，分别仅为0．083μg／g、0．097μg／g和0．010μg／g。因此，牙鲆肌肉是人类微量元素的良好来源。     

在线渗析-离子色谱法测定水产品中多聚磷酸盐的研究

文章采用离子色谱法，结合在线渗析技术对水产品中多聚磷酸盐的质量分数进行了测定。该方法测定多聚磷酸盐离子在质量浓度0—10．0mg·L-1线性关系良好，相关系数达到0．999。检出限为3．0～10μg·L-1，回收率为95．8％～104％，连续进样检测值相对标准偏差小于10％。试验结果显示该法分离度好，灵敏度高，检测结果准确，操作方便快速，适合水产品中多聚磷酸盐的测定。     

黄海硬骨鱼类鱼卵,仔稚鱼及其生态调查研究

阐述了黄海硬骨鱼类鱼卵、仔稚鱼的种类组成、数量分布及产卵场的生态特点。共鉴定68种硬骨鱼类的鱼卵、仔稚鱼，其中61种鉴定到种，隶属于7目、36科、56属。春季产卵的5种，春夏季37种，夏季7种，夏秋季4种，秋季7种，秋冬季1种，冬季1种，冬春季2种，春夏秋季3种。主要产卵场为海州湾渔场、青海渔场、石岛渔场和海洋岛渔场，形成产卵场的表层水温都在8℃以上，产卵的最适表层水温为15．0－23．0℃；盐度为31．50～33．00。并对海州湾的鱼卵、仔稚鱼种类组成的变化、高眼鲽的分布范围以及自然海域中浮性鱼卵成活状况进行了讨论。     

dcELISA检测泥鳅、鲫肌肉中氯霉素残留方法的应用

应用直接竞争酶联免疫吸附试验方法（dcELISA）快速定量测定泥鳅、鲫肌肉中氯霉素（CAP）残留量。氯霉素浓度在0．05～10ng/g范围内具有良好的线性关系，线性方程为y=-0．33—1．88x，r^2=0．995，向样品中分别添加0．1、0．3、0．9ng/g3个浓度水平的氯霉素标准品，泥鳅样品的平均回收率分别为87．2％、88．9％、93．0％，鲫样品的平均回收率分别为86．1％、79．9％、99．0％，最低检测限为O．05ng/g，批内变异系数为8．0％，批间变异系数为7．2％，结果表明该方法灵敏度高，重复性好，适合在泥鳅、鲫肉样中氯霉素残留筛选检测。     

高效液相色谱法测定卤虫无节幼体中精胺含量

本研究建立了高效液相色谱法测定卤虫无节幼体中精胺含量的方法。样品经5％三氯乙酸溶液提取，提取液采用丹璜酰氯柱前衍生，以甲醇一水为流动相，经C18反相色谱柱分离后用紫外检测器检测。精胺的线性范围为0．1～1000μg/ml，线性相关系数为0．9999，检出限为0．06μg/ml。3个添加浓度（0。1、1．0和5.0μg/m1）的平均回收率为86．3％～96.39/6，相对标准偏差皆小于59/6。采用此方法对卤虫中精胺进行检测，其精胺含量为0．077mg/g。本方法具有分析时间短、线性范围宽、灵敏度和精密度高等优点，适合于卤虫中精胺的检测．     

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.