金沙江攀枝花江段棒花鱼的生物学

在2006年5月和2006年12月至2007年5月期间,通过使用三层定置刺网捕捉棒花鱼,我们研究了金沙江中游攀枝花江段棒花鱼的生物学。棒花鱼在三层定置刺网中的平均出现率为93.1%,在总渔获物中的平均重量百分比为7.68%;雄性个体的平均体长显著大于雌性个体,体长和体重的回归方程为:W=4×10-5L2.8499(W为体重,L为体长,R2=0.8614);根据鳞片年轮对82尾标本进行了年龄鉴定,其中0龄个体1尾,占1.22%;1龄个体68尾,占82.93%;2龄个体13尾,占15.85%。鳞径与体长显著相

我国淡水鱼类粘孢子虫的支序分类学研究

本研究选取15个主要特征对我国淡水鱼类23属粘孢子虫的支序分类进行了分析。结果表明,根据这15个特征构建的经典分支系统树与现有分类系统较为一致;而许多被分子系统学证明有争议的特征,如尾孢虫的尾突,孢子和极囊的形状等在研究粘孢子虫的系谱发育中仍然有着重要作用,剔除了上述特征的分支系统树与经典的分支系统树相比,存在许多缺陷。嗜碘泡是区分粘体虫和碘泡虫的主要特征,然而剔除嗜碘泡特征的分支系统树与经典的分支系统树区别不大,因此,我们建议在这一方面和国际学术界统一起来,即不再把嗜碘泡作为区分碘泡虫和粘体虫的主要特征

水色及其与藻类的关系

水色是水环境质量评价中一个重要的综合性指标,不同的水色反映水质的营养状况;藻类群落是水体营养状况的生物表征,对水色具有重要影响作用。本文通过分析不同水色中的藻类优势种群及其作用,认为藻类优势种群是决定水色的主要生物因子;阐明了藻类与水色之间的相互关系以及施肥改变水色的内在机理,水体营养状况决定了水体藻类群落结构进而决定不同的水色;并结合实践对如何判断不同藻类种群引起的不同水色提出了看法,同时对改变和调控水色的方法和途径进行了论述,为相关生产和水环境管理提供理论依据和技术指导。

滇池非封闭围隔水体底栖动物的监测调查

报道了昆明滇池蓝藻水华污染控制技术中,非封闭围隔水体试验区马村湾、海东湾底栖动物1年的定量、定性监测结果。调查中共采到底栖动物27科、68种;定量采样点底栖动物全年平均密度为7198.11条/m2,生物量为60.16g/m2;分析了本底调查与监测调查中种类的消长、分布;评价了底栖动物与其它生物及生境的关系。

钟形钟虫形态学及表膜下纤维系统的研究

利用活体观察及蛋白银染色技术对钟形钟虫的形态学及表膜下纤维系统进行了研究 ,分别给出活体及蛋白银制片后标本的鉴别特征及表膜下纤维系统。本种活体鉴定主要特征为虫体呈宽钟状 ,细胞质不透明 ,镜下明显可见有散布的脂滴存在。蛋白银制片特征为口器明显呈横位 ,第 1(P1)和第 2咽膜 (P2 )汇合后形成的短咽膜弯曲程度较甚。纵向纤维粗壮而稀疏 ,40— 5 0条 ;口围盘纤维网粗壮 ,呈轮辐状排布 ,相邻两轮辐外部末端多呈闭合态 ;第 3咽膜 (P3)由 3排毛基索组成 ,其靠近P2 侧的一列毛基索在P1与P

鲫耳石年轮的观察及其确证

对耳石边缘年轮形成周期进行了分析。结果表明 ,鲫耳石上 1a形成 1个年轮 ,年轮形成时期洪湖种群主要在 4～ 6月 ,洞庭湖种群主要在 3～ 5月。星耳石和微耳石一样 ,可用于鲫年龄鉴定 ,而且不经磨片即可直接读取年轮 ,完整星耳石和微耳石与微耳石磨片上的年轮读数的吻合率均在 80 %以上 ,误差不超过 1龄。但相对而言 ,微耳石上年轮更易观察。文中对耳石形态和年轮特征作了描述

西藏的脆杆藻科和短缝藻科(羽纹纲)硅藻

本文报道了在西藏发现的硅藻门,羽纹纲,无壳缝目,脆杆藻科中的8个属及拟壳缝目,短缝藻科中的1个属,共134个分类单位(包括68种,63变种,3变种变型),其中等片藻属中的1变种,脆杆藻属中的1种4变种及短缝藻属中的8种1变种为中国新记录。

Monitoring of organochlorine pesticides using PFU csystems in Yunnan lakes and rivers, China

Polyurethane foam unit (PFU) systems were collected from 11 lakes and three rivers in the Yunnan Plateau, China and, the PFU extrusion liquids, were analyzed for organochlorine pesticides (OCPs) by gas chromatography with electron capture detection (GCECD). The concentrations of pp'-DDE, HCB and HCHs were undetectable to 1.86 mu g l(-1) (mean 0.27 mu g l(-1)), undetectable to 0.72 mu g l(-1) (mean 0.11 mu g l(-1)), and 0.24-21.95 mu g l(-1) (mean 7.39 mu g l(-1)) respectively in lakes; and those in rivers were undetectable to 0.23 mu g l(-1) (mean 0.08 mu g l(-1)), 0.68-2.93 mu g l(-1) (mean 1.70 mu g l(-1)), and 2.71-37.56 mu g l(-1) (mean 17.01 mu g l(-1)) respectively. Notably, some residue levels of OCPs exceeded the US National Recommended Water Quality Criteria, implying Yunnan has levels of OCPs potentially harmful to human health. Further, the contamination by OCPs showed an obvious spatial distribution pattern. Amongst the lakes, Dianchi, Xingyun, Lugu and Yangzonghai had the highest OCP levels dominated by beta-HCH, whereas among rivers, Nujiang and Lancang Rivers had the highest contents of OCPs dominated by alpha-HCH. This demonstrates that HCHs are the predominant contaminants and some point sources of HCHs may still exist in Yunnan. The pollution levels in Yunnan were compared with other studies, suggesting the PFU method is suitable for long-term on-line monitoring of trace OCPs in aquatic ecosystems. Therefore, continuous studies monitoring OCPs in lakes and rivers are needed to further understand the future trend of contamination. (c) 2006 Elsevier Ltd. All rights reserved.

Effects of animal-plant protein ratio in extruded and expanded diets on nitrogen and energy budgets of juvenile Chinese soft-shelled turtle (Pelodiscus sinensis Wiegmann)

In this study, we investigated the effects of animal-plant protein ratio in extruded and expanded diets on nutrient digestibility, nitrogen and energy budgets of juvenile soft-shelled turtle (Pelodiscus sinensis). Four extruded and expanded feeds (diets 1-4) were formulated with different animal-plant protein ratios (diet 1, 1.50:1; diet 2, 2.95:1; diet 3, 4.92:1; diet 4, 7.29:1). The apparent digestibility coefficients (ADCs) of dry matter and crude lipid for diet 1 were significantly lower than those for diets 2-4. There was no significant difference in crude protein digestibility among diets 1-4. The ADC of carbohydrate was significantly increased with the increase in animal-plant protein. Although nitrogen intake rate, faecal nitrogen loss rate and excretory nitrogen loss rate of turtles fed diet 1 were significantly higher than those fed diets 2-4, nitrogen retention rate, net protein utilization and biological value of protein in these turtles were significantly lower than those fed diets 2-4. In addition, energy intake rate, excretory energy loss rate and heat production rate of turtles fed diet 1 were also significantly higher than those fed diets 2-4. Faecal energy loss was significantly reduced with the increase in the animal-plant protein ratio. The ADC of energy and assimilation efficiency of energy significantly increased with a higher animal-plant protein ratio. The growth efficiency of energy in the group fed diet 1 was significantly lower than those in the groups fed diets 2-4. Together, our results suggest that the optimum animal-plant protein ratio in extruded and expanded diets is around 3:1.

Energy budget of Nile tilapia (Oreochromis niloticus) in relation to ration size

Nile tilapia weighing 8.29-11.02 g were fed a practical diet at seven ration levels (starvation, 0.5, 1, 2, 3, 4% body weight per day and satiation) twice a day at 30 degrees C. Feed consumption, apparent digestibility, nitrogenous excretion and growth were determined directly, and heat production was calculated by difference of energy budget. The relationship between specific growth rate in wet weight (SGR(w), percentage per day) and ration size (RL, percentage per day) was a decelerating curve described as SGR(w) = 2.98 (1 - e(-0.61(RL-0.43))). The apparent digestibility coefficients for dry matter and protein showed a decreasing pattern with increasing ration while the apparent digestibility coefficient of energy was not significantly affected by ration size. The proportion of gross energy intake lost in nitrogenous excretion tended to decrease with increasing ration. Feed efficiency was highest, and the proportion of gross energy intake channelled to heat production was lowest, at an intermediate ration level (2% per day). The energy budget at the satiation level was: 100IE = 16.9FE + 1.2(ZE + UE) + 62.3HE + 19.6RE, where IE, FE, (ZE + UE), HE and RE represent gross energy intake, faecal energy, excretory (non-faecal) energy loss, heat production and recovered energy (growth), respectively. (C) 1997 Elsevier Science B.V.