3种观赏水草对水体镉污染修复效果的比较研究

在实验条件下,研究了斯必兰(Gymnocorovis spilanthoides)、羽毛草(Myriophyllum aquaticm)和水芹(Oenanthe javanica)3种观赏水草对不同浓度的镉污染水体(Cd2+0.5、1.0、5.0、10.0 mg/L)的修复效果以及镉对这3种观赏水草生长的影响.研究结果表明:3种观赏水草均对水体镉污染有一定程度的抗性并能不同程度地去除水体中的镉,其抗性和去除效率的大小均表现为斯必兰＞水芹＞羽毛草;3种观赏水草对镉的富集能力也为斯必兰＞水芹＞羽毛草.以上实验结果表明,在3种观赏水草中斯必兰对水体镉污染的耐性最高、修复能力最强.     

太平洋牡蛎单体苗种生产及养殖技术的研究

本项研究采用先固着后脱基或肾上腺素（ＥＰＩ）诱导方法生产太平洋牡蛎（Ｃｒａｓｓｏｓｔｒｅａｇｉｇａｓ Ｔｈｕｎｂｅｒｇ）单体苗种获成功。选用价格低廉的聚丙烯扁条包装带作为固着基，待牡蛎苗生长至０．５ｃｍ以上时，来回弯曲进行剥离，可容易获得单体牡蛎。１９９２年在１２０ｍ＾３水体中获得平均壳高０．５ｃｍ单体牡蛎４０３６．７万粒，单位水体出苗量３３．６４万粒；使用肾上腺素诱导太平洋牡蛎眼点幼虫，最佳诱导     

烟台浅海区不同养殖系统养殖效果的比较

于１９９８年４月５日至６月２３日，在山东烟台市四十里湾海区进行了３种养殖模式养殖效果比较的模拟实验。在该海区岸边建立了栉孔扇贝（Ｃｈａｍｙｓ ｆａｒｒｅｒｉ）单养，栉孔扇贝和海带（Ｌａｍｉｎａｒｉａ ｊａｐｏｎｉｃａ）混养，栉孔扇贝、海带和刺参（Ａｐｏｓｔｉｃｈｏｐｕｓ ｊａｐｏｎｉｃｕｓ）混养等３个系列、９个养殖系统和１个对照系统（５．０ｍ＊２．０ｍ＊１．０ｍ，日换水量１００％），进行对比实验。     

三道河水库浮游甲壳动物群落结构特征的初步研究

研究了湖北省三道河水库２００７年８月至２００８年４月浮游甲壳动物的群落结构及现存量的时空变化。三道河水库６个采样点（Ⅰ ～Ⅵ）共鉴定出浮游甲壳动物８科、１３属、２１种，其中枝角类５科、９属、１４种，优势种为简弧象鼻蟤（Ｂｏｓｍｉｎａｃｏｒｅｇｏｎｉ）、短尾秀体蟤（Ｄｉａｐｈａｎｏｓｏｍａｂｒａｃｈｙｕｒｕｍ）和透明蟤（Ｄａｐｈｎｉａｈｙａｌｉｎ）；桡足类３科、４属、７种，优势种为广布中剑水蚤（Ｍｉｃｒｏｃｙｃｌｏｐｓｌｅｕｃｋａｒｔｉ）和汤匙华哲水蚤（Ｓｉｎｏｃａｌａｎｕｓｄｏｒｒｉｉ）。浮游甲壳动物年平均密度为９２．６个／Ｌ，枝角类和桡足类分别为３６．９个／Ｌ和５５．７个／Ｌ；平均生物量为１．１２６ｍｇ／Ｌ，枝角类和桡足类分别为０．７３７ｍｇ／Ｌ和０．３８９ｍｇ／Ｌ。浮游甲壳动物现存量的季节变化明显，密度和生物量由高到低依次为秋季＞夏季＞冬季＞春季。浮游甲壳动物密度的水平分布差异明显，采样点的密度和生物量由高到低为Ⅱ ＞Ⅵ ＞Ⅲ ＞Ⅰ ＞Ⅳ ＞Ⅴ。     

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。     

4种常用药物对黄鳝苗种急性毒性研究

采用常温静水实验法，进行孔雀石绿、高锰酸钾、敌百虫、强氮精对黄鳝（Ｍｏｎｏｐｔｅｒｕｓ ａｌｂｕｓ）（体长１１～１５ｃｍ，平均体重３．６克／尾）的急性毒性试验。结果表明：４种药物对黄鳝苗种的９６ｈ半致死浓度（９６ｈＬｃ５０）分别为３．６５４、５．７７５、７．４０７、１８．５２０ｍｇ／Ｌ；安全浓度（Ｓｃ）分别为０．３６５４、０．５７７３、０．７４０７、１．８５２ｍｇ／Ｌ。黄鳝苗种对高锰酸钾最敏感，敌百虫次之；最不敏感的为强氮精，其次为孔雀石绿。     

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     

中国对虾与罗非鱼施肥混养的基础研究↑（*）

用４个海水池塘陆基围隔（５ｍ×５ｍ），进行了封闭式施肥混养中国对虾（Ｐｅｎａｅｕｓｃｈｉｎｅｎｓｉｓ）与台湾红罗非鱼（Ｏｒｅｏｃｈｒｏｍｉｓｍｏｓａｍｂｉｃｕｓ×Ｏ．ｎｉｌｏｔｉｃｕｓ）的基础研究。结果表明，在不同密度条件下，对虾成活率４５．０％～８６．７％（平均６６４．２％），产量为７５．７～１１１．８ｋｇ／ｈｍ２（５７ｄ），生产力为０．１９／ｍ２·ｄ。池塘对中国对虾的负荷力为１７０．０ｋｇ／ｈｍ２。其中某些围隔对虾死亡较多的原因是负荷量超过了负荷力，发生饵料缺乏和自残。在限定罗非鱼放养量（８×１０３尾／ｈｍ２）的条件下，鱼虾最适放养尾数配比为１∶３，中国对虾（体长５．５５ｃｍ）的最适放养量为２４×１０３尾／ｈｍ２左右。     

蛤蟆通水库乌鳢的生物学及其渔业利用

本文报道了蛤蟆通水库的乌鳢生物学特性和讨论了乌鳢在渔业生产发展中的作用。捕捞群体中平均体长２１．４—６６ｃｍ，体重１１８—３５１０ｇ，体重体长关系式为ｌｏｇＷ＝３．０４６６ｌｏｎｓＬ１．９６６６。３＋龄达到性成熟，雌雄性比为１：０．９７；个体繁殖力Ｙ（千粒鱼卵）与体长Ｌ（ｃｍ）相关关系式为Ｙ＝２．５９７４Ｌ－７８．９１８３。５月下旬一６月下旬在水库岸边有水草处筑巢产卵，卵为浮性。水温２３—２５℃时，受精卵约３天孵出仔鱼。     

南美白对虾淡水养殖池塘进苗后的苗种二次淡化方法

１．购买苗种要求：规格０．８－１．０ｃｍ，经过初步淡化，须淡化至１．００５（即７．５‰）即可。 ２．暂养池要求：在池塘的一角围出若干平方米的暂养池（用彩条布围拦），暂养池面积大小按１０００尾／ｍ２设计，暂养池的水深须在０．５ｍ以上，并在暂养池内安装气头，须连续进行供气，同时将暂养池的盐度调到５‰（即每立方水体投入５ｋｇ盐巴），事先将水质进行消毒（采用二溴海因０．２－０．３ｐｐｍ泼洒）、肥水（用生物肥水精培藻，每亩投放４ｋｇ，使水色呈茶褐色），并将ｐＨ调整到８．０以上（可采用生石灰）。 ３．放苗后的…     

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.