硅藻对渔业的支撑作用与负面效应探讨

传统认为,硅藻在水域食物链"硅藻—桡足类—鱼类"中起着支配作用,但近来的研究结果对此认为提出了质疑。为了深入探明硅藻在其中的作用机理,从硅藻对渔业正反两方面的作用进行了综述分析。     

The risk of parasite transfer to juvenile fishes by live copepod food with the example Triaenophorus crassus and Triaenophorus nodulosus

Natural zooplankton is a potential food resource for juvenile fish in fish farms as it is a good source of fats, carbohydrates, and protein. However, it is also a potential source of parasites and pathogens. The present study was conducted (1) to estimate the risk of parasite transfer by live copepod food under intensive farming conditions using the parasites Triaenophorus crassus and Triaenophorus nodulosus as example and (2) to look for strategies to avoid parasite infestation of juvenile fish.An easy and routinely applicable aniline blue staining method was developed to check the infestation levels of copepods with procercoids during the on-growing season of juvenile fish. From the copepod species occurring in zooplankton Cyclops spp. was infested frequently (9.4 ± 12.0%, maximum 38.7%), Diaptomus spp. infrequently (1.5 ± 1.6%, maximum 3.2%), Daphnia spp. never. Juvenile grayling, Thymallus thymallus, and corgonids, Coregonus sp., which had been fed with natural zooplankton revealed infestations rates with T. crassus of circa 5%, with T. nodulosus of circa 10%. As the occurrence of procercoids in the zooplankton was temporary limited, Triaenophorus infestation can be avoided by using artificial food instead of live copepods during the risky season.To prevent parasite infestation of juvenile fish methods were investigated to eradicate procercoids from copepods by chemical treatment (sodium chloride, hydrogen peroxide, citric acid treatment) and by freeze-thawing methods. Chemical methods failed to remove procercoids. In fish, which had been fed with frozen thawed zooplankton, no Triaenophorus spp. infestation was observed. Their survival rates were similar as in the control fed with live zooplankton, however the weight of the fish was significantly lower.     

大亚湾桡足类的生态学研究

根据2003年12月～2004年9月对纬度22.617°以北的大亚湾海域进行4个航次海域生态环境监测的资料,对大亚湾浮游桡足类的种类组成、生态类群、数量的季节变化和平面分布进行了分析。结果表明,所记录的54种浮游桡足类中,以红纺锤水蚤、亚强真哲水蚤、微刺哲水蚤和锥形宽水蚤的数量最丰富。桡足类种类数和丰度均以夏季最高,春季最低。通过这次调查,得出以下结论:大亚湾桡足类种类较多,是浮游动物第一大类群,但数量上次于毛颚类和枝角类;夏、秋2季是桡足类数量的高峰期,都以红纺锤水蚤占绝对优势;该次调查中大亚湾出现的浮游桡足类分属热带大洋类群、近岸低盐类群和广布类群,种类组成属印度西太平洋热带边缘区系。     

El Nino／La Nina影响下北部湾海域浮游桡足类种类组成与多样性

以1998年1月至1999年5月对北部湾海域进行的4个航次生态环境综合调查的资料为基础,分析El Nino／La Nina期间北部湾四季浮游桡足类种类组成与多样性,并对其与气候及海洋水文的关系进行初步探讨。结果显示,调查期间共出现浮游桡足类122种,其中32种周年出现,以春（82种）、夏（84种）较多,秋（52种）、冬（67种）较少;四季共出现优势桡足类13种,以广温广盐类型占主导,除微刺哲水蚤（Canthocalanus pauper）外,其余12种为季节性优势种;冬、夏两季受El Nino影响较大,优势种以中型桡足类为主;秋、春季大型桡足类优势地位较高,受La Nina影响明显;北部湾浮游桡足类多样性较高。分析表明,夏季北部湾水温和盐度对浮游桡足类群落多样性有一定影响,但在其他季节,这种影响不明显。     

黄海主要桡足类的生物量

本文采用个体重量计数法对黄海海区及各分区水域中的浮游桡足类的生物量及其组成进行了统计分析.结果表明,在浮游桡足类的生物量中起重要作用的有小拟哲水蚤Paracalanus parvus,大同长腹剑水蚤0ithona similis,中华哲水蚤Calanus sinicus,短角长腹剑水蚤0ithona brevicornis,强额拟哲水蚤Paracalanus crassirolris,双刺纺锤水蚤Acartia bifilasa,近缘大眼剑水蚤Corycaeus affinis及克氏纺锤水蚤Acartca clausi等8种.其中除中华哲水蚤体型较大外,其它7种均属中小型浮游桡足类.且其生物量的大部分是由2～4种桡足类的生物量所组成.     

基于枝角类和桡足类多样性的白洋淀水环境监测与评价

雄安新区的建立促使白洋淀水环境及生物资源监测与保护尤为重要。为研究白洋淀枝角类和桡足类群落结构时空变化特征及与水环境因子的相互关系,运用典型相关分析（canonical correlation analysis ,CCA）对2019年春季、夏季、秋季所测定的白洋淀枝角类和桡足类丰度、多样性指数及水环境因子进行多元统计分析。基于DNA条形码技术鉴定出白洋淀枝角类和桡足类共8 科17属26种,全年分布的优势种有简弧象鼻溞（Bosmina coregoni）、透明温剑水蚤（Thermocyclops hvalinus）和胸饰外剑水蚤（Ectocyclops phaleratus）。丰度和生物多样性指数特征存在时空差异,主要表现为区域性分布变化大于季节性变化,且在空间上均表现为南部区域大于北部区域。枝角类和桡足类与水环境相关性结果表明,温度（T）、透明度（TMD）、营养盐等通过影响枝角类和桡足类生长发育、摄食、繁殖等活动来调节其丰度及群落组成结构特征,而S、Pb、Zn为关键影响因子,对枝角类和桡足类丰度呈显著负相关。对白洋淀进行长期的物种研究和生态环境监测及保护,可以为水利工程实施和雄安新区建设提供参考,实现资源可持续利用和发展。     

巢湖的太湖新银鱼食物组成分析

[目的]为了分析巢湖银鱼产量变化的原因。[方法]于2006年11月和2007年8月9、月在5个采样点分别进行调查,研究了巢湖的太湖新银鱼食物组成、生长指标,并结合历史资料分析了巢湖银鱼产量变化的原因。[结果]结果表明,桡足类是太湖新银鱼的主要食物,在8月份食物中平均个数组成比例和出现率分别为66.32%±11.85%和100%,枝角类平均个数组成比例为27.77%±10.11%,出现率为100%,轮虫很少;在9月份食物中平均个数组成比例和出现率分别为57.86%±31.00%和87.18%,食物中枝角类平均个数组成比例为29.35%±28.06%,出现率为74.36%,轮虫极少。[结论]随着富营养化加重、蓝藻频繁暴发,巢湖中浮游动物数量在不断减少,而鲚鱼数量的不断增加对银鱼产生巨大食物竞争。此外,巢湖的银鱼大量感染双线绦虫,大量感染寄生虫肯定会对银鱼的生长和繁殖产生不利影响。     

麒麟菜养殖区海域浮游桡足类种类组成与多样性

[目的]研究麒麟菜养殖区海域浮游桡足类种类组成与多样性。[方法]于2011年1～12月对麒麟菜养殖区海尾镇海域进行生态环境调查,分析麒麟菜养殖海区浮游桡足类种类组成与多样性,并对其与季节及麒麟菜养殖的关系进行了初步探讨。[结果]此次调查期间共出现了浮游桡足类56种,其中有13种是全年出现的,以夏、秋季较多,春、冬较少;四季共出现优势桡足类9种,出现的生态类型有近岸低盐型、广温广盐型、高温广盐型,其中以近岸低盐类型占主导。麒麟菜丰富区域浮游桡足类种类多样性高于麒麟菜不丰富区域。[结论]麒麟菜养殖和季节变化对浮游桡足类多样性有一定的影响。     

Exploring the potential of providing and feeding pikeperch larvae (Sander lucioperca L.) with euryhaline copepod nauplii: A zoo technical trial

Egg hatching and nauplii success from three euryhaline calanoid copepod species at low salinities suggest a promising alternative initial live feed for pikeperch (Sander lucioperca L.) to the conventional live feed. Acartia bifilosa and Eurytemora affinis are viable candidates with egg hatching down to zero salinity, and Acartia tonsa nauplii survive up to 2 h at zero salinity after transfer from low-salinity seawater. When offered A. tonsa and Artemia, pikeperch larvae equally consumed both prey types. We suggest that euryhaline copepods can be a supplement to or even a substitute for the normal live feed currently used as larval feed for pikeperch.