上海市河道的氮源污染物及其对食蚊鱼急性毒性的初步研究

2008年6～8月对上海市内4条不同生态类型河道（午潮港、横港、朝阳河、曹杨环浜）的水质状况及鱼类组成进行调查。结果显示，除曹杨环浜外，所调查的其他3条河道普遍受氨氮污染，氨氮含量均超过了地表水环境标准V类水的限值2．0mg／L；污染河道中鱼类种类极少，入侵鱼种食蚊鱼（Gambusia affinis）已成为其中的广布种。进一步选取上述调查河道中典型的氮类污染因子氨氮、亚硝酸盐作为暴露物，采用静水生物法对食蚊鱼进行96h急性毒性试验，发现食蚊鱼对氨氮的耐受性较高，24、48、72、96h的半致死浓度（LC50）分别为80．00、54．81、52．78、44．58mg／L；对亚硝酸氮的耐受性相对较低，24、48、72、96h的LC50分别为9．19、7．46、6．06、5．99mg／L。由于不同鱼类对环境污染物的耐受性和适应性不同，其种类组成易受河道污染程度影响，而食蚊鱼由于其对氨氮较高的耐受性，已成为上海各污染河道中的主要鱼种，进一步探讨其适应机制，将有助于了解河道生态类型的发展趋势及演变过程。     

环境因子对广东城市湖泊后生浮游动物的影响

对广东省14个主要城市湖泊进行了调查采样分析.检到的轮虫中占据种类组成和丰度优势的为集中分布于热带和亚热带地区的种类,后生浮游动物丰度与叶绿素含量呈显著正相关(r=0.426, P<0.01),其中轮虫丰度与叶绿素含量呈显著正相关(r=0.534, P <0.01),枝角类丰度和叶绿素含量相关性不明显.广东省城市湖泊中大多数均有鱼类,在人工专门放养鱼类的湖泊,枝角类、桡足类的丰度和相对丰度普遍更低,以小型的浮游动物轮虫占据绝对优势.在有水生植物的湖泊,枝角类、桡足类的相对丰度较高.后生浮游动物丰度与富营养评分结果呈显著正相关(r=0.374, P<0.01).其中,轮虫丰度与富营养评分结果呈显著正相关(r=0 479, P<0 01),后生浮游动物丰度与总氮(r=0.286, P<0.05)、高锰酸盐指数(r=0.289, P<0.05)、悬浮物含量(r=0 404, P<0.01)呈正相关,与透明度(r=-0.242)、pH(r=-0.237)呈负相关.根据各湖后生浮游动物组成进行聚类分析,结果表明广东城市湖泊3个分类的后生浮游动物优势种均为富营养化指示种,说明后生浮游动物分布受到水体富营养化的影响.     

环境因子对广东城市湖泊后生浮游动物群落的影响

通过对广东主要城市湖泊调查采样分析，结果表明：检到的轮虫中占据种类组成和丰度优势的为集中分布于热带和亚热带地区的种类，后生浮游动物丰度与叶绿素含量呈显著正相关(r=0.426, p<0.01)，其中轮虫丰度与叶绿素含量呈显著正相关(r=0.534, p<0.01)，枝角类丰度和叶绿素含量相关性不明显。广东省城市湖泊中大多数均有鱼类，在人工专门放养鱼类的湖泊，枝角类、桡足类的丰度和相对丰度普遍更低，以小型的浮游动物轮虫占据绝对优势。在有水生植物的湖泊，枝角类、桡足类的相对丰度较高。后生浮游动物丰度与富营养评分结果呈显著正相关(r=0.374, p<0.01)，其中轮虫丰度与富营养评分结果呈显著正相关(r=0.479, p<0.01)，后生浮游动物丰度与总氮(r=0.286, p<0.05)、高锰酸盐指数(r=0.289, p<0.05)、悬浮物含量(r=0.404, p<0.01)呈正相关，与透明度(r=-0.242)、pH(r=-0.237)呈负相关。根据各湖后生浮游动物组成进行聚类分析表明广东城市湖泊各分类后生浮游动物优势种均为富营养化指示种，受到水体富营养化影响。     

渫水河砷污染环境中浮游动物的群落特征研究

受高砷背景的影响,渫水河及其支流存在不同程度的砷污染,为揭示砷污染的生态效应,探寻防治对策,研究了该水域中浮游动物的种群分布和季节变化,分析其密度与砷含量及TN、TP的关系.2006-2007年共进行3次调查,设置8个采样断面;共检出浮游动物166种,其中,原生动物(95种)＞轮虫(55种)＞桡足类(10种)＞枝角类(6种);丰水期有104种,远大于平水期和枯水期.浮游动物现存量以丰水期最高,其次是平水期,枯水期最少;空间分布上以断面Ⅱ最高,黄水河支流高于渫水河干流,而渫水干流中段的现存量最小.种类组成上,由于桡足类和枝角类对重金属污染较为敏感,检出种类极少,且均是耐污型,轮虫则以α-β型种类为主,纤毛虫比例不高,只在断面Ⅱ和断面Ⅳ超过肉足虫比例.渫水河的Shannon-Wiener多样性指数、Simpson物种多样性指数、Margalef物种丰富度指数和Pielou均匀度指数值均＜2.生物多样性指数与As含量不相关(r=0.674),但轮虫密度与As含量显著相关(r=0.931).浮游动物密度与TN显著相关(r=0.826),TN对渫水河的浮游动物群落组成起着关键作用,而As只对轮虫的生物量影响较大,并不能决定整个浮游动物的群落结构.     

牧野湖浮游动物群落结构及其与环境因子的相关性研究

2011年7月至2012年6月,调查分析了新乡市牧野湖和上游河道的浮游动物群落结构及其丰度与环境因子的相关性.共检测出浮游动物23属、43种(不包括原生动物);其中,轮虫15属、26种,枝角类5属、11种,桡足类6属、6种;浮游动物总丰度季节性变化为夏季＞春季＞秋季＞冬季,各季节间差异性极显著(P＜0.01).浮游动物总丰度的空间变化表现为静水区(S3)＞湖心区(s4)＞下游区(水车处)(S5)＞上游截止闸(S2),各样点间差异极显著(P＜0.01).相关性分析显示,牧野湖浮游动物总平均丰度与叶绿素a、CODcr、水温极显著正相关(P＜0.01),与N03-N浓度(P=0.006)极显著负相关、与透明度(P=0.018)显著负相关.浮游动物丰度主要受叶绿素a、水温、CODCr、N03-N和透明度的影响.     

不同洪水阶段对升金湖后生浮游动物群落结构特征的影响

为了解不同洪水阶段对升金湖后生浮游动物群落结构特征的影响，于2020年7月初（洪水前（Phase 1））、7月下旬（洪水形成期（Phase 2））、8月中旬（洪水中期（Phase 3））和9月下旬（洪水后（Phase 4））在升金湖湖区水域设置24个采样点进行后生浮游动物采样调查。研究期间共采集到后生浮游动物20科50属86种，其中轮虫11科29属55种，枝角类5科13属23种，桡足类4科8属8种。方差分析显示后生浮游动物密度在不同洪水阶段差异极显著（F=8.301，P<0.01）。四个阶段轮虫共同优势种为暗小异尾轮虫（Trichocerca pusilla）、广生多肢轮虫（Polyarthra vulgaris）、圆筒异尾轮虫（Trichocera cylindrica）、螺形龟甲轮虫（Keratella cochlearis）、裂痕龟纹轮虫（Anuraeopsis fissa），枝角类共同优势种为简弧象鼻溞（Bosmina coregoni）、颈沟基合溞（Bosminopsis deitersi）、脆弱象鼻溞（Bosmina fatalis），桡足类四个阶段没有共同优势种。后生浮游动物密度和生物量平均值分别为2170.20±506.74 ind./L和7.79±2.04 mg/L。平均密度和平均生物量峰值均出现在洪水前，最低值分别出现在分别出现在洪水中期和洪水形成期。Shannon Wiener多样性指数、Margalef丰富度指数和Pielou均匀度指数的变化范围分别为2.37~4.50、2.19~6.50和0.83~1.21。Pearson相关性分析结果表明后生浮游动物密度与电导率、水深呈显著负相关，生物量与溶解氧、电导率、水深、浊度呈显著负相关，与总氮含量、硝氮含量呈显著正相关。研究揭示了不同洪水阶段对通江湖泊后生浮游动物的影响：洪水改变了湖泊后生浮游动物的物种组成及优势种，且显著影响后生浮游动物的密度及多样性。     

太湖贡湖湾大型浮游动物群落结构的季节变化

2006年7月至2007年6月对太湖贡湖湾浮游动物群落结构的季节变化进行了研究。整个研究期间,贡湖湾共鉴定出浮游动物35种;浮游动物年平均密度为467 ind.•L-1,年平均生物量为1.726 mg•L-1。贡湖湾浮游动物优势种为针簇多肢轮虫 (Polyarthra trigla) 和萼花臂尾轮虫 (Brachionus Calyciflorus),其中针簇多肢轮虫年平均密度为99 ind.•L-1,占浮游动物总数量的22 %,萼花臂尾轮虫年平均密度为49 ind.•L-1,占浮游动物总数量的11%。相关分析表明,轮虫数量与颗粒悬浮物浓度和桡足类生物量显著负相关;枝角类数量与轮虫生物量显著负相关;桡足类数量与水温和总磷呈显著正相关性,与枝角类生物量极显著正相关。     

勤得利湾浮游动物群落结构特征

2003年5、7、9、11月对勤得利湾浮游动物的种类组成结构特征进行了研究。结果表明：浮游动物共计4门82种,以原生动物、轮虫为主,分别占29.27%和54.88%；前节晶囊轮虫、锥形似铃壳虫、螺形龟甲轮虫、尖削叶轮虫、萼花臂尾轮虫、多足变形虫、单缩虫等为优势种。浮游动物数量为27449.1 ind．/L,原生动物数量为11445 ind．/L,占41.7%；生物量为14.235 mg/L,轮虫最高,为11.002 mg/L。浮游动物季节变化比较明显,数量夏季最高为74431.2 ind．/L；生物量以夏季最高37.9056 mg/L；水平分布采样点Ⅲ最高,为42113.2 ind．/L和21.836 mg/L。勤得利湾浮游动物多样性指数变化是冬季＞春季＞秋季＞夏季。均匀度指数变化是秋季＞冬季＞春季＞夏季。     

锦江河特有鱼类国家级水产种质资源保护区浮游动物群落结构

为研究锦江河特有鱼类国家级水产种质资源保护区浮游动物群落结构特征,于2015年1月、4月、7月和10月按季度在锦江河保护区进行采样分析。结果显示,在保护区共采集到浮游动物4门51属82种,轮虫类、原生动物、桡足类和枝角类物种数占浮游动物物种总数的比例分别为46.34%、29.27%、15.85%和8.54%。优势种类为4门6属16种,其中轮虫类6种,原生动物4种,枝角类4种,桡足类2种。保护区浮游动物密度变幅为297.76~1 430.10 ind/L,平均为855.13 ind/L;生物量变幅为5.73~26.36 mg/L,平均为14.37 mg/L;群落丰富度指数(D_m)变幅为3.18~4.90,平均为3.96;香农指数(H')变幅为2.11~3.12,平均为2.81;均匀度指数(J')变幅为0.81~0.89,平均为0.86。研究表明,在被摄食压力下降及饵料生物资源下降的共同影响下,保护区外界环境对个体较小的原生动物和轮虫有利,群落生态优势度也集中于上述浮游动物类群。受到水文特征的影响,锦江河核心区的浮游动物物种数、密度和生物量以及多样性指数总体高于实验区。     

济南地区水域春、秋两季浮游动物群落结构与环境因子的关系

为了解济南地区水域浮游动物群落结构特征,于2015年春季(5月)和秋季(11月)对济南地区水域24个采样点位进行了采样调查。结果表明,两季节共鉴定出浮游动物50种,春季浮游动物共计4类46种,以枝角类为主,平均密度为3 421.67ind./L;秋季浮游动物共4类34种,以轮虫为主,平均密度为1 686.67ind./L。春季浮游动物香农威纳指数平均值为1.89,均匀度指数平均值为0.76,秋季浮游动物香农威纳指数平均值为1.92,均匀度指数平均值为0.74,典范对应分析结果显示:春季总硬度和电导率是影响浮游动物群落的主要环境因子,秋季总氮和氨氮及总碱度是影响浮游动物群落的主要环境因子。通过综合分析得出结论,济南地区水域呈中度污染。     

Protein and amino acid composition from the mantle of juvenile O ctopus vulgaris exposed to prolonged starvation

Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg^?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg^?1 protein) than essential amino acids (425.82 ± 9.15 g kg^?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting.     

美人鱼发光杆菌对凡纳滨对虾非特异性 免疫功能及抗病力的影响

在基础饲料中分别添加0.1%和1%美人鱼发光杆菌灭活菌、0.1%美人鱼发光杆菌活菌配制成3种免疫实验饲料,以基础饲料为空白对照组饲料,每组设3个平行样。对个体质量为(4.83±0.36)g的凡纳滨对虾进行为期20 d的饲养实验,分别在0、5、10、15和20d进行取样,以血清中的酚氧化酶(PO)、酸性磷酸酶(ACP)、碱性磷酸酶(AKP)、超氧化物歧化酶(SOD)和溶菌酶(UL)活性为免疫指标,探讨了美人鱼发光杆菌作为免疫制剂对凡纳滨对虾非特异性免疫效应的影响;在投喂免疫饲料后的第22天,按0.004 2 kg/kg体重的剂量,直接投喂对虾白斑综合征病毒(WSSV)病料,并记录累积死亡率。结果表明,美人鱼发光杆菌免疫实验组对凡纳滨对虾血清中PO、ACP、AKP、UL和SOD活性影响明显高于对照组,并且在饲料中添加美人鱼发光杆菌后,明显提高了对虾抵御WSSV感染的能力。其中0.1%美人鱼发光杆菌活菌实验组的抗病毒感染能力最强,WSSV感染14d内累计死亡率为63.3%±5.8%;而对照组为96.7%±3.3%。研究表明,美人鱼发光杆菌添加在对虾饲料中能提高凡纳滨对虾非特异性免疫水平,增强抵抗疾病的能力,将其作为对虾免疫增强剂具有良好的应用前景。     

Effects of Spirulina platensis as a feed additive on growth and coloration of blue dolphin cichlids (Cyrtocara moorii Boulunger, 1902)

This study was carried out to investigate the effects of replacing fish meal with dietary Spirulina as a feed supplement on the growth performance and coloration of blue dolphin cichlids (Cyrtocara moorii). Five isonitrogenous (47% crude protein) and isocaloric (17.36 kJ/g digestible energy) diets were for formulated to replace FM with 0, 5, 10, 15 and 20% Spirulina (designated as Control, SP5, SP10, SP15 and SP20 respectively) and fed to the fish (initial body weight, 3.15 ± 0.01 g). Fish were randomly distributed into fifteen 120 L aquariums (26.5 ± 1.00°C), 15 fish per aquarium. The diets were tested in triplicate for 12 weeks. Experimental groups were fed twice daily (09:00 and 17:00) by hand to satiation. At the end of the feeding trial, significantly (p < 0.05) higher weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER) and lower feed conversion ratio (FCR) were observed in fish fed the SP10 diet when compared to the SP20 diet. There was no significant difference in these parameters between the other groups. The skin coloration of blue dolphin cichlid fed a diet containing Spirulina meal was enhanced. The best coloration was observed in the SP15 group. These impressions were objectively validated by chemical determinations of carotenoids extracted from fish skins and passed statistical tests of significance. The study findings show that Spirulina meal does not diminish growth rates except at very high levels.     

Dietary thiamin and pyridoxine requirements of fingerling Indian major carp,Cirrhinus mrigala (Hamilton)

Two experiments were conducted to quantify the dietary thiamin (experiment I) and pyridoxine (experiment II) requirements of fingerling Cirrhinus mrigala for 16 weeks. In experiment I, dietary thiamin requirement was determined by feeding seven casein–gelatin‐based diets (400 g kg^?1 CP; 18.69 kJ g^?1 GE) with graded levels of thiamin (0, 0.5, 1, 2, 4, 8 and 16 mg kg^?1 diet) to triplicate groups of fish (6.15 ± 0.37 cm; 1.89 ± 0.12 g). Fish fed diet with 2 mg kg^?1 thiamin had highest specific growth rate (SGR), protein retention (PR), RNA/DNA ratio, haemoglobin (Hb), haematocrit (Hct), RBCs and best feed conversion ratio (FCR). However, highest liver thiamin concentration was recorded in fish fed 4 mg thiamin kg^?1 diet. Broken‐line analysis of SGR, PR and liver thiamin concentrations exhibited the thiamin requirement in the range of 1.79–3.34 mg kg^?1 diet (0.096–0.179 μg thiamin kJ^?1 gross energy). In experiment II, six casein–gelatin‐based diets (400 g kg^?1 CP; 18.69 kJ g^?1 GE) containing graded levels of pyridoxine (0, 2, 4, 6, 8 and 10 mg kg^?1 diet) were fed to triplicate groups of fish (6.35 ± 0.37 cm; 1.97 ± 0.12 g). Fish fed diet containing 6 mg kg^?1 pyridoxine showed best SGR, FCR, PR, RNA/DNA ratio, Hb, Hct and RBCs, whereas maximum liver pyridoxine concentration was recorded in fish fed 8 mg kg^?1 dietary pyridoxine. Broken‐line analysis of SGR, PR and liver pyridoxine concentrations reflected the pyridoxine requirement from 5.63 to 8.61 mg kg^?1 diet. Data generated during this study would be useful in formulating thiamin‐ and pyridoxine‐balanced feeds for the intensive culture of this fish.     

Sea bream culture in Egypt; status, constraints and potential

Marine fish farming in Egypt began in 1976 with the culture of gilthead sea bream, (Sparus aurata) as this fish was notably adaptable to brackish and marine pond conditions. Today, marine fish and shrimp farms amount to about 19,000 ha, out of which 42% is already in production while the rest, i.e., 58% is still under construction. In 1997, cultured gilthead sea bream production of 2,250 tons made up 3% of the 75,000 tons total aquaculture catch. In polyculture, usually with the grey mullet and sea bass, gilthead sea bream contributed 440 kg ha^–1 to the total yield of 1,700 kg ha^–1 (26%) over a period of 16 months. For the same period, the yield of monoculture ponds averaged 100 kg ha^–1, while in marine cages, yields ranged from 4–10 kg m³. In 1996–1997, fry of 0.25–1 g and fingerlings 1–10 g with a total of 3 million, were collected from the wild and 1 million fry were produced in the three marine hatcheries out of the four existing ones. The development of sea bream culture in Egypt is now severely inhibited by the shortage of seeds and adequate feeds. Exports of both sea bream and sea bass, during 1994–1996 averaged 1,300 tons per year.     

A Minchinia mercenariae‐like parasite infects cockles Cerastoderma edule in Galicia (NW Spain)

The cockle Cerastoderma edule fishery has traditionally been the most important shellfish species in terms of biomass in Galicia (NW Spain). In the course of a survey of the histopathological conditions affecting this species in the Ria of Arousa, a haplosporidan parasite that had not been observed in Galicia was detected in one of the most productive cockle beds of Galicia. Uni‐ and binucleate cells and multinucleate plasmodia were observed in the connective tissue mainly in the digestive area, gills and gonad. The parasite showed low prevalence, and it was not associated with abnormal cockle mortality. Molecular identification showed that this parasite was closely related to the haplosporidan Minchinia mercenariae that had been reported infecting hard clams Mercenaria mercenaria from the Atlantic coast of the United States. The molecular characterization of its SSU rDNA region allowed obtaining a fragment of 1,796 bp showing 98% homology with M. mercenariae parasite. Phylogenetic analysis supported this identification as this parasite was clustered in the same clade as M. mercenariae from the United States and other M. mercenariae‐like sequences from the UK, with bootstrap value of 99%. The occurrence of M. mercenariae‐like parasites infecting molluscs outside the United States is confirmed.     

A novel approach to denitrification processes in a zero-discharge recirculating system for small-scale urban aquaculture

This paper presents an innovative process to solve the nitrate build-up problem in recirculating aquaculture systems (RAS). The novel aspects of the process lie in a denitrification bioreactor system that uses solid cotton wool as the primary carbon source and a unique degassing chamber. In the latter, the water is physically stripped of dissolved gaseous O₂ (by means of a Venturi vacuum tube), and the subsequent denitrification becomes more efficient due to elimination of the problems of oxygen inhibition of denitrification and aerobic consumption of cotton wool. The cotton wool medium also serves as a physical barrier that traps organic particles, which, in turn, act as an additional carbon source for denitrification. Operation in the proposed system gives an extremely low C/N ratio of 0.82 g of cotton wool/g of nitrate N, which contributes to a significant reduction of biofilter volume. The additional advantage of using solid cotton wool as the carbon source is that it does not release organic residuals into the liquid to be recycled. Operation of the system over a long period consistently produced effluents with low nitrate levels (below 10 mg N/l), and there was only a very small need to replace system water. The overall treatment scheme, also incorporating an aerobic nitrification biofilter and a granular filtration device, produced water of excellent quality, i.e., with near-zero levels of nitrite and ammonia, a sufficiently high pH for aquaculture, and low turbidity. The proposed system thus provides a solution for sustainable small-scale, urban aquaculture operation with a very high recovery of water (over 99%) and minimal waste disposal.     

Fertilization by refrigerator stored sperm of the Indian major carp, Labeo calbasu (Hamilton, 1822)

This study reports on the spermatological properties, and on the development of a protocol for refrigerator storage (4°C) of Labeo calbasu (Hamilton, 1822) sperm for artificial breeding. Volume, motility, concentration and pH of the freshly collected sperm were 2.21 ± 0.53 (μL g^?1 of fish weight) (mean ± SD), 95 ± 1 (%), 1.93 ± 0.44 × 10⁹ (cells mL^?1) and 7.56 ± 0.17 respectively. Sperm activation was evaluated at different osmolalities of NaCl solution, and motility ceased completely when osmolality of the extender was ≥287 mOsmol kg^?1. Sperm retained motility for 24, 72 and 108 h, after refrigerator storage when sperm were undiluted, suspended in Alsever's solution and suspended in Alsever's solution containing 5% methanol respectively. Fertilization rate of fresh eggs with sperm stored at 4°C in Alsever's solution and Alsever's solution containing 5% methanol was 77% and 60% with a hatching rate of 60% and 43% respectively. The fertilization and hatching success of the stored sperm suggests potential to use refrigeration for transporting genetic material to hatcheries for artificial breeding of L. calbasu in Bangladesh.     

Effects of metomidate anaesthesia or transfer to pur sea water on plasma parameters in ammonia-exposed Atlantic salmon (Salmo salar L) in sea water

Atlantic salmon (Salmo salar L) postsmolts weighing 150 ± 53 g were exposed to 14–15 mg l^–1 TA-N (total ammonia-N) in sea water in 1 m³ tanks for 24h. Blood samples were then taken A) immediately after the fish were netted from the exposure tanks and stunned by a blow to the head; B) 2–20 min after the fish were transferred to 15 l of an anaesthetic solution of metomidate in ammonia-free sea water; or C) 2–20 min after the fish were transferred to 15 l of ammonia-free sea water. Plasma TA-N level was 18% lower in the anaesthetised fish compared to in the fish sampled directly from the exposure tanks (p 0.05), and accordingly 16% lower in the fish transferred to pure sea water although this difference was not significant (p = 0.07). Plasma glucose level was higher in the fish transferred to pure sea water than in the fish receiving the two other treatments (p 0.05), but plasma urea, osmolality, Na^{+, Cl–, Ca2+ or Mg2+} levels did not vary significantly between the different treatments. Plasma TA-N level increased with time in the fish in the metomidate solution (p 0.02).