浙南主要养殖海域环境和贝类两种重金属含量调查研究

为研究浙南地区(台州、温州)主要养殖海域的海水、表层沉积物及缢蛏、泥蚶、青蛤等主要养殖贝类产品中重金属Hg、As的污染状况,利用原子荧光光谱法对样品中的重金属含量进行了测定。结果表明:浙南海域的海水、沉积物中,汞、砷含量符合无公害产地环境质量标准,贝类中汞、无机砷含量符合无公害贝类质量标准,但缢蛏、青蛤中的无机砷含量仍然较高,应进一步加强监测。     

深沪湾海水、沉积物及贝类体内重金属的含量与评价

利用1998年5月和9月深沪湾海域环境调查资料，着重分析了深炉湾海水、表层沉积物及褶牡蛎和菲律宾蛤仔体内重金属的含量及分布，结果表明：深沪湾海水中Cu、Pb、Cd、Zn、Hg等含量均低于渔业水质标准，而表层沉积物的Pb、Zn含量大部分已超标，近岸水域海水和表层沉积物中Cu、Pb、Cd、Zn的含量明显高于湾中心水域，湾顶水域高于湾口水域。Hg的含量是湾南部水域高于北部水域。文中还根据全国海岸带污染综合调查专业组制定的海洋生物污染评价标准，对2种贝类的重金属污染程度进行评价，结果深沪湾的养殖贝类体内的重金属含量均未超标。     

乳山和广饶养殖贝类重金属含量分析及食用健康风险评估

采用单因子污染指数法分析了2015年上市出售前乳山海域养殖的太平洋牡蛎和广饶海域养殖的毛蚶、菲律宾蛤仔、文蛤、四角蛤等5种常见贝类中铜、铅、镉、铬、总汞等重金属的残留水平,并采用点估计法,通过计算贝类体内的重金属暴露风险商(HQ)评价食用上述5种贝类可能导致的健康风险。结果显示,不同种类的贝类中重金属含量差异较大,太平洋牡蛎中的铜和镉以及毛蚶中的铅含量较高,处于中污染水平,其他贝类中的重金属含量较低。然而暴露风险商(HQ)结果显示,成人和儿童仅在过量食用乳山养殖太平洋牡蛎时会存在镉的暴露健康风险,其中儿童受到的风险高于成年人,太平洋牡蛎中镉的摄食风险应该引起重视。本研究为建立适合中国的膳食暴露评估模型,制定合理的水产品中重金属污染物限量标准提供了参考。     

5种经济贝类在天津大港滩涂的养殖适应性研究

通过养殖试验,分析5种主要经济贝类的生长、存活及其养殖区的底质、生物饵料,探讨其在天津大港滩涂的养殖适应性。结果表明,5—8月份,贝类生长较慢,死亡率较高,9—11月份则相反;试验区夏季底质浮泥层较厚,海水中饵料生物缺乏,春秋季节则相反;该滩涂适于养殖长牡蛎、毛蚶,较适于养殖菲律宾蛤仔、青蛤,不适于养殖缢蛏。     

山东省主要贝类养殖区重金属环境状况及贝类安全风险分析

依据2014年8月对山东省近岸贝类养殖区的调查资料,研究了养殖区海水、沉积物和生物体中6种重金属的含量及富集情况,并对贝类养殖区进行质量及生态风险评价.结果显示,海水中重金属含量从高到低为As、Cu、Cr、Pb、Cd和Hg;沉积物中重金属含量从高到低为Cr、Pb、Cu、As、Cd和Hg;贝类体中重金属含量从高到低为Cu、As、Cd、Cr、Pb和Hg.生态环境质量评价结果表明,养殖区海水中重金属含量均符合Ⅱ类海水水质标准;沉积物重金属含量均符合Ⅰ类海洋沉积物质量标准;贝类体中Hg、Cd、Pb和Cr均符合《食品安全国家标准食品中污染物限量》,Cu符合Ⅰ类海洋生物质量标准.贝类对重金属的富集能力从大到小为Cu、Cd、Hg、Pb、Cr和As,调查海域贝类体中的Cu、Cd富集系数较高,其他重金属富集系数相对较低.重金属质量安全风险分析表明,贝类体中Cd、Pb、As、Cr和Hg的膳食暴露量较低,处于安全范围内,但建议去除内脏后食用.     

乳山湾水体重金属含量的季节变化与养殖贝类对水体重金属的生物富集效应

为了解乳山湾近岸海域重金属污染情况及养殖贝类对重金属富集情况,按春、夏、秋、冬四个航次采集湾内和湾外的表层海水,并于秋季采集湾内养殖的太平洋牡蛎(Crassostrea gigas)分析海水及牡蛎体内Cu、Pb、Zn、Cr、Cd、As、Hg等7种重金属含量,评价海水质量与养殖贝类的食用安全。结果表明:乳山湾湾内湾外海域水质较好,除冬季Zn以及春、秋两季的Hg符合二类海水水质标准,其余点位均符合一类海水水质标准,海水水质为"清洁"。乳山湾湾内和湾外沉积物中各重金属的含量均低于第一类海洋沉积物标准,没有受到明显的污染。乳山湾内养殖牡蛎体内Cd和Zn的浓度远远高于湾内水体中重金属的浓度,表明太平洋牡蛎对重金属具有较强的富集作用,但仍符合二类海洋生物质量标准。     

菲律宾蛤仔养殖对底质AVS影响的模拟实验

采用模拟实验方法，研究了菲律宾蛤仔养殖对底质酸挥发硫的影响，分析了酸挥发硫与其他底质环境因子的关系。结果表明，菲律宾蛤仔养殖会增加底质中酸挥发硫的含量，而且酸挥发硫含量随养殖密度增加而升高；与酸挥发硫密切相关的环境因素有底质温度、氧化还原电位（Eh）值、有机物（OM）含量、Fe^3＋／Fe^2＋比值、硫酸盐还原菌（SRB）数量；菲律宾蛤仔的养殖导致沉积物中SEM和AVS的比值小于1，束缚了重金属的生物活性或生物毒性。     

汉沽养殖菲律宾蛤仔突发性死亡原因调查及分析

2012年9—10月,汉沽浅海底播菲律宾蛤仔发生大规模死亡,死亡率最高达86.2%,同时生长缓慢。调查结果显示,蛤仔死亡率随养殖密度增大而升高;海水和沉积物中重金属、石油烃等化学因子均未超标;6—8月叶绿素含量及初级生产力明显偏低;6月中旬出现寻氏肌蛤,9—10月减少、消失,同时蛤仔出现大规模死亡。推测蛤仔死亡原因为底质表层的寻氏肌蛤与蛤仔争夺近底海水中的饵料和溶氧,并通过足丝网络影响蛤仔的摄食及呼吸。较低的海域初级生产力也进一步加剧了蛤仔的死亡。     

重金属离子对菲律宾蛤仔呼吸代谢的影响

菲律宾蛤仔（Ruditapes philippinarum）是我国沿海重要的滩涂养殖贝类之一。国外专家学者对滤食性生物耗氧率做过较多的研究，而重金属离子对水生生物影响研究报道较少。本文通过测量耗氧量来探讨不同浓度的Cd^2＋、Cu^2＋、Zn^2＋对菲律宾蛤仔呼吸代谢的影响，旨在为研究水体中重金属污染生物机理和贝类能量学提供依据，所得结果可作为选择蛤仔养殖滩涂底质的重要依据，并有助于养殖过程中科学管理，提高滩涂养殖种类的质量和产量。     

辽东湾兴城海域增养殖区汞污染状况分析及健康风险评价

2013年通过采集兴城市邴家湾海水增养殖区的海水、沉积物和养殖贝类样品,利用原子荧光光度法测定总汞含量,综合监测数据对该养殖区渔业环境汞污染现状及健康风险进行分析评价。该海水增养殖区海水总汞含量范围在0.012~0.194μg/L;沉积物总汞含量范围在0.008 4~0.057 6mg/kg;养殖贝类总汞含量为0.006 10mg/kg,均符合国家标准。以100g/(人·d)的水产类摄食量估算,食用贝类汞摄入量占JECFA制定的汞暂定每周可耐受摄入量PTWI值的1.4%;甲基汞摄入量占PTWI值的4.2%;占美国EPA设定的甲基汞RfD值的9.7%。结果表明,辽东湾兴城海域所产贝类对消费者引起的汞暴露健康风险很小。     

Marine and coastal protected and conserved areas strategy in Brazil: Context,lessons, challenges,finance, participation,new management models,and first results

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Effects of levamisole,echinacea, and thyme oral administration on growth factors,blood parameters,and immunity in beluga,Huso huso

A total of 180 fish (95.50 g) were fed with 0.1% levamisole, 0.5% thyme, and 0.5% echinacea crude extract for 60 days. The control group received no stimulant. The results of growth parameters indicated a significant positive effect of levamisole in comparison with the control group, though it was not significantly different from echinacea and thyme treatments (P > 0.05). No mortalities were observed in the treatments. Feed conversion ratio and protein efficiency ratio did not differ significantly between the treatments. The highest numbers of white and red blood cells and the greatest amounts of hemoglobin and hematocrit were detected in the levamisole treatment, showing significant differences with the other groups in the percentage of hemoglobin only (P < 0.05). The highest levels of MCH and MCHC were also measured in the levamisole treatment. Differential count of white blood cells revealed no significant differences in neutrophil and lymphocyte levels with the control. There was a significant increase in the percentage of eosinophil in the levamisole treatment alone. No significant differences were recorded in total protein, albumin, and aspartate aminotransferase and alanine aminotransferase enzymes. Levamisole treatment displayed the highest activities of glutathione peroxidase and lysozyme as well as the greatest amount of immunoglobulin. So 0.1 levamisole yielded better results in the growth, blood, and immunity parameters and can be used as a stimulant without injuring body organs.     

Prevalence of nematode parasite,Contracaecum, in Nile tilapia,African catfish and Barbus species in Lake Hawassa,Ethiopia

A cross‐sectional study was conducted from November 2017 to March 2018 at Lake Hawassa to determine the prevalence of larval Contracaecum infestation in Nile tilapia, (Oreochromis niloticus), African Catfish (Clarias gariepinus) and Barbus species (Barbus intermedius). Fifty‐two point six per cent (52.6%) previous prevalence and 5% precision were used to estimate the sample size. Accordingly, a total of 383 randomly sampled fish species comprising of 163 (42.6%) C. gariepinus, 159 (41.5%) O. niloticus and 61(15.9%) B. intermedius were examined. The length and weight of each sampled fish were recorded. All the sampled fish were examined for the evidence of Contracaecum parasites in Hawassa University Veterinary Parasitology and Pathology Laboratory. Chi‐square values and comparison of proportions were used to analyse the data. The overall prevalence of Contracaecum parasites of fish population was 31.6%. The distribution of parasite was significantly affected by fish species (p = .000), sexes (p = .018), length (p = .003) and weight classes of fish (p = .026). As a hygienic problem and gutting activity conducted at the sides of the Lake Hawassa and distribution of discarded fish wastes for surrounding piscivorous birds by butchers and other people, the life cycle of Contracaecum parasite was perpetuated. Thus, the parasite is of zoonotic significance. Therefore, awareness creation activities for societies and control of fish parasites should be conducted in the study area.     

Inter-river, -annual and -seasonal variability in fecundity of Atlantic salmon, Salmo salar L., in rivers in Newfoundland and Labrador, Canada

Abstract  Fecundity is an integral component of the calculation of Atlantic salmon, Salmo salar L., egg depositions in rivers. Fecundity determinations can be time consuming and prohibitively expensive in terms of application on a broad scale. Consequently, where river specific and annual data are not available, default means are used in calculations in Newfoundland and Labrador. It is important therefore to know the extent of variability among rivers, years and seasons and the potential error involved in using default values. Annual fecundity data were available for one river in Labrador and nine rivers in Newfoundland. Fecundity was determined from ovaries collected in the recreational fishery in the summer for all 10 rivers. For three of these rivers, fecundity determined from summer sampling was compared with that obtained from sampling at time of spawning in autumn. There was significant variability in fecundity with length as a covariate among rivers, years and seasons. Mean number of eggs per female decreased between 8.3% and 29.0% from summer to autumn while mean number of eggs per cm decreased from 5.0% to 28.5%. Depending on the measure of relative fecundity used (no. of eggs kg⁻¹ or no. of eggs cm⁻¹), results of simulations showed that estimates of egg deposition incorporating defaults can deviate from those obtained by applying year-specific and river-specific values by 50–75%, without adjusting for the seasonal reduction in fecundity, and by 30–50% with an adjustment. A sensitivity analysis revealed that of three parameters used in the calculation of egg deposition (size, percent female and fecundity), fecundity was the most influential.     

中国综合水产养殖的发展历史、原理和分类

综合水产养殖是水产养殖的重要类型,它既包括同一水体内水生生物的混养,也包括水产养殖与同一水体或邻近区域进行的其他生产活动的结合。中国的稻田养鱼始于1 800年前,大规模的海水综合养殖始于公元1975年。目前中国开展的综合养殖模式有近百种,其依据的生态学原理主要有3个:通过养殖生物间的营养关系实现养殖废物的资源化利用;利用技术措施、养殖种类、养殖系统间功能互补或偏利作用平衡水质;养殖水体资源(时间、空间和饵料等)的充分利用。综合养殖系统可分为技术措施综合、养殖种类综合和系统综合三大类,其中系统综合类又可再分为水基系统综合和水基与陆基系统综合两个亚类。     

Seasonal variation in habitat use by salmon, Salmo salar, trout, Salmo trutta and grayling, Thymallus thymallus, in a chalk stream

Abstract A portable multi‐point decoder system deployed in a tributary of the River Itchen, a southern English chalk stream, recorded the habitats used by PIT‐tagged juvenile salmon, Salmo salar L., trout, Salmo trutta L. and grayling, Thymallus thymallus L., with a high degree of spatial and temporal resolution. The fishes’ use of habitat was monitored at 350 locations throughout the stream during September/October 2001 (feeding period) and January/February 2002 (over‐wintering period). Salmon parr tended to occupy water 25–55 cm deep with a velocity between 0.4 and 1.0 m s^?1. During both autumn and winter, first year salmon (0+ group) were associated with gravel substrate during the daytime and aquatic weed at night. In autumn, 1+ salmon were strongly associated with hard mud substrates during the day and with marginal tree roots at night. In winter, they were located on gravel substrate by day and gravel and mud at night. Trout were associated with a greater range of habitats than salmon, generally occupying deeper and faster water with increasing age. During the autumn, 0+ trout were located along shallow (5–10 cm) and slow (?0.1–0.4 m s^?1) margins of the stream, amongst tree roots by day and on silty substrates at night. During winter the 0+ trout occupied silty substrates at all times. As age increased, trout increasingly used coarse substrates; hard mud, gravel and chalk, and weed at night. All age groups of grayling (0+, 1+ and 2+) tended to occupy hard gravel substrate at all times and used deeper and faster water with increasing age. The 1+ and 2+ groups were generally found in water 40–70 cm deep with a velocity between 0.3 and 0.5 ms^?1, whilst the 0+ groups showed a preference for shallower water with reduced velocity at night, particularly in the winter. There were greater differences in the habitats used between species and age groups than between the autumn and winter periods, and the distribution of fish was more strongly influenced by substrate type than water depth or velocity. The results are discussed in relation to the habitat requirements of mixed salmonid populations and habitat management.     

Floods,drying, habitat connectivity,and fish occupancy dynamics in restored and unrestored oxbows of West Central Iowa,USA

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