乌苏里江上游黑斑狗鱼种群的生长特性

于2003年秋季对乌苏里江上游黑斑狗鱼Esox reicherti的种群结构和生长特性进行了调查研究,共采集样本840尾。结果表明:该水域的黑斑狗鱼主要由6+龄以下个体组成,其中以3+龄以下个体为主。体长与体重之间的关系为W=0.0051L3.1023(r=0.9762);生长方程为Lt=120.17[1-e-0.1215(t+0.5983)],Wt=15139.22[1-e-0.1215(t+0.5983)]3.1023;生长拐点年龄t=8.7龄,拐点体重W=4531.7 g,说明黑斑狗鱼在8#龄前均能维持较快增长。鉴于目前的捕捞状况,应对4#⁸#龄之间的个体适当加以保护。     

淀山湖翘嘴鲌繁殖力研究

为对淀山湖翘嘴鲌Culter alburnus种群数量变动、资源保护提供基础资料,对淀山湖翘嘴鲌个体繁殖力进行了研究。结果表明:调查样本个体繁殖年龄由3⁶龄构成,个体绝对繁殖力为22 7646龄构成,个体绝对繁殖力为22 764⁷37 760粒,平均为134 901粒;体长相对繁殖力为820737 760粒,平均为134 901粒;体长相对繁殖力为820¹3 982粒/cm,平均为3157粒/cm;体质量相对繁殖力为10413 982粒/cm,平均为3157粒/cm;体质量相对繁殖力为104⁵54粒/g,平均为234粒/g;个体绝对繁殖力、体长相对繁殖力与体长和体质量均呈幂函数关系,而体质量相对繁殖力仅与性腺成熟系数和卵巢质量相关。研究表明:淀山湖翘嘴鲌个体绝对繁殖力与体长、卵巢质量、性腺成熟系数和净体质量均呈正相关;体长相对繁殖力与卵巢质量、性腺成熟系数、净体质量和肥满度均呈正相关,与年龄呈负相关;体质量相对繁殖力与性腺成熟系数呈正相关,与卵巢质量呈负相关。     

淀山湖翘嘴鲌繁殖力研究

为对淀山湖翘嘴鲌Culter alburnus种群数量变动、资源保护提供基础资料,对淀山湖翘嘴鲌个体繁殖力进行了研究。结果表明:调查样本个体繁殖年龄由3~6龄构成,个体绝对繁殖力为22 764~737 760粒,平均为134 901粒;体长相对繁殖力为820~13 982粒/cm,平均为3157粒/cm;体质量相对繁殖力为104~554粒/g,平均为234粒/g;个体绝对繁殖力、体长相对繁殖力与体长和体质量均呈幂函数关系,而体质量相对繁殖力仅与性腺成熟系数和卵巢质量相关。研究表明:淀山湖翘嘴鲌个体绝对繁殖力与体长、卵巢质量、性腺成熟系数和净体质量均呈正相关;体长相对繁殖力与卵巢质量、性腺成熟系数、净体质量和肥满度均呈正相关,与年龄呈负相关;体质量相对繁殖力与性腺成熟系数呈正相关,与卵巢质量呈负相关。     

马苏大麻哈鱼形态性状对体质量的影响分析

为研究影响6月龄、18月龄马苏大麻哈鱼Oncorhynchus masou体质量的重点形态性状,采用数理统计方法,测量其体质量、叉长、全长、吻长、头长、眼径、尾柄长、尾柄高、头高和体高等10个性状,并分析了各形态性状间的相关性。结果表明:6月龄马苏大麻哈鱼除眼径与体质量间的相关性为显著水平(P<0. 05)外,其余各性状与体质量间的相关性均达到了极显著水平(P<0. 01),而18月龄马苏大麻哈鱼各个形态性状与体质量之间的相关性均达到了极显著水平(P<0. 01);通径分析结果表明,影响6月龄马苏大麻哈鱼体质量(Y6)的关键性状为叉长(FL)、头长(HL)和尾柄长(CPL),而影响18月龄该鱼体质量(Y18)的关键性状则是全长(TL)、体高(BD)、尾柄高(CPD)和头高(HD);采用多元逐步回归分析方法建立以形态性状为自变量,体质量为因变量的多元回归方程,6月龄、18月龄鱼体质量的回归方程分别为Y6=-9. 6+1. 414FL+3. 604 HL-1. 585CPL,Y18=-362. 624+14. 321TL+14. 35BD+29. 031CPD+14. 673HD。本研究结果可为马苏大麻哈鱼人工增养殖过程中的苗种选育提供数据资料。     

两种壳色文蛤壳形态性状对活体质量的影响

为了解文蛤Meretrix meretrix壳形态性状对活体质量的影响,获得具有优良遗传性状的群体,以经过7年群体选育的F_4代黑斑文蛤和红色文蛤为试验对象,采用相关性分析、主成分分析和通径分析等统计方法,对两种文蛤进行了壳长(X_1)、壳高(X_2)、壳宽(X_3)对活体质量(Y)的影响分析,建立了壳形态性状对活体质量影响的最优回归方程。结果表明:两种文蛤表型性状差异不大(P>0.05),但壳性状对活体质量的主要影响因子不同,壳高和壳宽是决定黑斑文蛤活体质量的主要因素,而壳长是决定红色文蛤活体质量的主要因素(P<0.01);多元逐步回归分析得到最优回归方程Y_(黑斑)=-8.308+0.361X_2+0.391X_3,Y_(红色)=-8.389+0.500X_1,回归关系和偏回归系数均达极显著水平(P<0.01)。本研究结果对生产实践中两种文蛤的选育具有较高的参考价值。     

两种壳色文蛤壳形态性状对活体质量的影响

为了解文蛤Meretrix meretrix壳形态性状对活体质量的影响,获得具有优良遗传性状的群体,以经过7年群体选育的F_4代黑斑文蛤和红色文蛤为试验对象,采用相关性分析、主成分分析和通径分析等统计方法,对两种文蛤进行了壳长(X_1)、壳高(X_2)、壳宽(X_3)对活体质量(Y)的影响分析,建立了壳形态性状对活体质量影响的最优回归方程。结果表明:两种文蛤表型性状差异不大(P>0.05),但壳性状对活体质量的主要影响因子不同,壳高和壳宽是决定黑斑文蛤活体质量的主要因素,而壳长是决定红色文蛤活体质量的主要因素(P<0.01);多元逐步回归分析得到最优回归方程Y_(黑斑)=-8.308+0.361X_2+0.391X_3,Y_(红色)=-8.389+0.500X_1,回归关系和偏回归系数均达极显著水平(P<0.01)。本研究结果对生产实践中两种文蛤的选育具有较高的参考价值。     

尼罗罗非鱼的形态性状对体重影响效果的分析

随机选取1龄尼罗罗非鱼Oreochromis niloticus同批雌雄个体121尾,其中雌鱼57尾,雄鱼64尾,分别测量其体重(Y)及体长(X1)、头长(X2)、躯干长(X3)、体高(X4)、尾柄长(X5)、尾柄高(X6)、体宽(X7)等7项形态性状。采用相关分析和通径分析方法,以形态性状为自变量,体重为依变量,计算相关系数、通径系数和决定系数,并建立形态性状对体重的多元回归方程。结果表明:尼罗罗非鱼雌、雄鱼的7个形态性状与体重的相关性均达到极显著水平(P<0.01);影响雌鱼体重的主要性状为体长、体高、体宽和头长,影响雄鱼体重的主要性状为体高、体长、躯干长、和体宽;体长对雌鱼体重的决定系数最大(0.178),体高对雄鱼体重的决定系数最大(0.136)。经多元回归分析,选择偏回归系数显著的变量,与体重建立多元回归方程,尼罗罗非鱼雌雄鱼的形态性状与体重的多元回归方程分别为:Y雌=-443.542+16.525X1-17.106X2+40.658X4+56.038X7和Y雄=-684.921+15.531X1+25.413X3+38.976X4+48.213X7。     

乌江中游佛顶山平舟原缨口鳅的繁殖生物学特征

为研究乌江流域平舟原缨口鳅Vanmanenia pingchowensis的繁殖生物学特征,于2017年1月—12月至2018年3、6、9月在乌江中游佛顶山支流采集平舟原缨口鳅标本262尾,测定其体长、体质量和性腺质量等基础数据,分析了性比、副性征、卵径、繁殖力和性成熟系数等繁殖生物学特征。结果表明:雌雄群体年龄分布在3⁺～6+～6⁺龄,优势年龄组均为4+龄,优势年龄组均为4⁺和5+和5⁺龄;协方差分析显示,雌鱼的体长、体质量关系与雄鱼存在显著性差异(P<0.05);雌雄鱼副性征不明显,繁殖季节性比为1.53∶1;用Logistic方程推算初次性成熟理论值,雌性体长58.72 mm、体质量3.83 g、年龄2.93 a,雄性体长52.45 mm、体质量1.99 g、年龄3.05 a;绝对繁殖力为739～2953粒,平均(1629±520)粒,体质量相对繁殖力为150.5～358.4粒/g,平均(250.2±58.5)粒/g;雌鱼Ⅳ期卵巢中存在明显的两批卵子,发育类型为分批同步型,产卵类型为完全同步型;卵径频率分布显示,平舟原缨口鳅繁殖期在5—7月。研究表明,当前乌江佛顶山平舟原缨口鳅繁殖群体大龄化趋势明显,补充群体严重不足,建议从保护现有种群和人工增殖两方面采取措施进行保护。     

凡纳滨对虾生长及养殖池氮、磷收支随养殖时间的变化

研究了室内不同养殖时间凡纳滨对虾Litopenaeus vannamei的生长及养殖池氮、磷收支与水质的变化。试验设4组,养殖时间分别为20、40、60、80 d。结果表明:在各养殖时间段,养殖池的主要水质指标pH、DO、TAN、NH3-N、NO-2-N、CODMn均控制在对虾生长的安全范围内;试验虾体长(L)和体质量(W)间的关系均符合幂函数方程W=aLb(a=0.0126～0.0135,b=2.7919～2.8873);体长和养殖时间(t)的关系符合线性方程L=at+b(a=0.0673～0.0818,b=1.7310～2.1536);体质量和养殖时间的关系符合线性方程W=at+b(a=0.0187～0.0496,b=-0.3390～0.0535);成活率(S)和养殖时间的关系符合对数方程S=-11.807 ln t+100.66;不同养殖时间段,各试验池氮、磷的主要输入源均为饲料,其次为初始水层,虾苗体氮、磷输入最少,而收获虾输出的氮、磷占总氮、总磷输出的比例随养殖时间的延长呈下降趋势。     

去氧肾上腺素维持腰-硬联合麻醉下剖宫产术中血液循环稳定的观察

目的:观察用微量泵持续静脉推注去氧肾上腺素对腰-硬联合麻醉下剖宫产术中血液循环稳定的影响。方法:选择100例择期剖宫产产妇,随机分为F组(在鞘内注局麻药即刻以25¹00μg/min静脉泵入去氧肾上腺素维持循环稳定)和M组(根据血压下降程度,静注麻黄碱5 mg)。记录麻醉后多时点的血压,心率,恶心、呕吐发生情况,失血量,输液量,新生儿生后Apgar评分情况,胎儿娩出即刻脐静脉血血气分析指标。结果:F组各时点观察指标均优于M组(P<0.05),与麻醉前比较差异无统计学意义(P>0.05);M组各时点血压与麻醉前比较差异有统计学意义(P<0.05),心率在麻醉后5 min时减慢(P<0.05);F组脐静脉血气pH值、BE值均高于M组(P<0.05),PaCO2低于M组(P<0.05);F组恶心、呕吐率低于M组(P<0.05)。结论:以25100μg/min静脉泵入去氧肾上腺素维持循环稳定)和M组(根据血压下降程度,静注麻黄碱5 mg)。记录麻醉后多时点的血压,心率,恶心、呕吐发生情况,失血量,输液量,新生儿生后Apgar评分情况,胎儿娩出即刻脐静脉血血气分析指标。结果:F组各时点观察指标均优于M组(P<0.05),与麻醉前比较差异无统计学意义(P>0.05);M组各时点血压与麻醉前比较差异有统计学意义(P<0.05),心率在麻醉后5 min时减慢(P<0.05);F组脐静脉血气pH值、BE值均高于M组(P<0.05),PaCO2低于M组(P<0.05);F组恶心、呕吐率低于M组(P<0.05)。结论:以25¹00μg/min静脉泵入去氧肾上腺素,更能稳定腰-硬联合麻醉下剖宫产术中产妇的血液循环。     

白斑狗鱼与黑斑狗鱼的形态差异与判别分析

将传统形态学测定和框架测定相结合,采用聚类分析、主成分分析和判别分析3种多元分析方法,对自斑狗鱼Esox lucius和黑斑狗鱼Esox reichrti的不同地理居群共115尾标本的36个测量性状和12个可数性状数据进行统计分析,以探讨两种狗鱼的形态差异。可数性状卡方检验结果表明,白斑狗鱼与黑斑狗鱼的背鳍棘数、臀鳍棘数、臀鳍分支鳍条数、纵行鳞数、侧线上鳞以及侧线下鳞差异极显著。在可量性状上,聚类分析与主成分分析结果一致,黑斑狗鱼乌苏里江种群与嫩江种群差异最小,首先聚为一支,后与黑龙江种群聚为一支,两种狗鱼差异明显,白斑狗鱼为单独一支。判别分析结果表明,不同种群形态差异极显著(P<0.01),判别准确率P_1为96.4%～100%。分析结果显示两种狗鱼在形态上已产生一定程度的差异。     

Selective exploitation of large pike Esox lucius--effects on mercury concentrations in fish populations

The present study outlines two main trends of mercury transfer patterns through the fish community: 1) the Hg concentrations increase with increase in the trophic level, with top predators having the highest concentrations, and 2) a fast growth rate may dilute the concentrations of Hg in fish muscle tissue (growth biodilution). In 2004, an extensive reduction in number of large pike (Esox lucius L.), was initiated by selective gillnet fishing in Lake Arungen, Norway, in order to increase the pike recruitment due to an expected reduction in cannibalism. In this connection, total mercury (THg) concentrations in the fish community were studied both before (2003) and after (2005) the removal of large pike. The delta(15)N signatures and stomach content analyses indicated that pike and perch (Perca fluviatilis L.) occupied the highest trophic position, while roach (Rutilus rutilus (L.)) was at the lower level, and rudd (Scardinius erythrophthalmus L.) at the lowest. The piscivores, pike and perch, had the highest concentrations of THg. The biomagnification rate of THg through the food web in the fish community was 0.163 (per thousand delta(15)N), with the highest uptake rate (0.232) in perch. A significant decrease in THg concentrations was found in all fish species in 2005 compared to 2003. Removal of the top predators in an Hg contaminated lake might thus be an important management tool for reducing Hg levels in fish, thereby reducing health risk to humans.     

水平荷载作用下嵌岩桩的桩端约束分析

本文从地质条件、施工设备及施工工艺等方面分析嵌岩桩在水平荷载作用下的桩端实际约束情况,同时介绍了该状态下桩身变形及内力分析方法,并以此为判定桩身质量的依据之一,对类似工程的处理及研究有一定的借鉴价值。     

Determination of mercury in freeze-dried muscle samples of pike, cod and perch using an ASV-technique

Determination of mercury in fish muscle samples can be made by an anodic stripping voltammetric technique (ASV) using a gold disc as the working electrode. Prior to analysis deep-frozen fish were thawed and then dissected using quartz scalpels. The freeze-dried samples were homogenised by the brittle fracture technique. Two wet digestion procedures were investigated, namely the HNO3/HCIO4 and the HNO3/H2SO4 system, and both were found to be useful. In order to complete the oxidation, the sample had to be UV-irradiated. The stripping procedure can be done in either a new medium - 0.1 M HCIO4 and 2.5 mM HCl - or directly in the sample solution. Using HNO3 and H2SO4 as oxidising agents and subsequently stripping the mercury directly in the sample solution is recommended, as the analytical procedure will be simpler and more time-saving. The concentrations obtained for pike, cod and perch, caught at a near-shore Baltic Sea station off the Forsmark nuclear power plant in Sweden, were 19.6, 0.84 and 5.1 (micrograms/g dry weight), respectively. On comparison with results obtained from neutron activation analysis, good agreement was found.     

Effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on early life stages of the pike (Esox lucius L.)

Freshly fertilized pike eggs were exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) at concentrations of 0.1, 1.0 and 10 ppt (ng/liter) for 96 hours. At all concentrations examined egg development was retarded by 23%, and the growth of fry was also significantly retarded for a long period after exposure. A dose-related mortality was observed. Highest mortality rates occurred during resorption of the yolk and reached almost 100 percent at a concentration of 10 ppt. Death was preceded by development of severe generalized edemas.Histopathologically edemas and hemorrhages were observed, together with alterations of bloodvessel walls. In the liver, two stages of pathological changes were distinguished. The first was characterized by a dilation of sinusoids and a slight swelling of hepatocyte nuclei; in the second stage the nuclei were enlarged up to twice the normal diameter. Hepatocytes were degenerated and varied in size and shape and liver architecture was a almost completely lost.     

Radiocesium in muscle tissue of reindeer and pike from northern Sweden before and after the Chernobyl accident. A retrospective study on tissue samples from the Swedish Environmental Specimen Bank.

After the Chernobyl accident in April 1986, considerable deposition of radionuclides occurred regionally in eastern, central and northwestern Sweden. Locally, the fallout of radiocesium exceeded the remainder from atmospheric nuclear weapons tests by several magnitudes. Since the end of the 1960s samples of organs from various plant and animal species, annually collected at different localities, have been preserved in the Swedish Environmental Specimen Bank (ESB). In this work samples from the ESB have been used for retrospective studies of radioactive pollution. The activities of Cs-134 and Cs-137 in muscle tissues from reindeer, Rangifer tarandus, and pike, Esox lucius, preserved in the ESB, were measured. The samples were collected annually; the reindeer at three localities in northern Sweden and the pike at one of them. In material collected prior to the Chernobyl accident, the levels of Cs-137 were 57-180 Bq/kg in reindeer and 14-24 Bq/kg in pike, fresh weight basis. These levels relate to earlier nuclear bomb tests. A significant decrease was found in pike during the pre-Chernobyl period (1971-86). In post-Chernobyl samples the burden of Cs-137 varied from amounts equal to the former levels in the northernmost locality and up to 80 times higher for the maximum values in the southernmost locality. The highest value recorded was 18,425 Bq/kg in reindeer. The geographic variations in reindeer from Chernobyl fallout were in accordance with the pattern of deposition estimated by aircraft surveys performed in May 1986. The ratio between 'new' and 'old' radiocesium burdens in pike, caught in 1987, approached the corresponding ratio for reindeer grazing in the precipitation area of the lake; 33 and 19, respectively.