Assessing the green sea urchin (Strongylocentrotus drobachiensis) stock in Maine, USA

The green sea urchin (Strongylocentrotus drobachiensis) fishery is of great importance to Maine’s economy. The fishery took off in the late 1980s as a result of expanding export markets, but has experienced substantial decline in landings since 1992 because of large decreases in urchin stock abundance. Fishery-independent surveys have not been conducted, and no formal stock assessment has been done prior to this study. Using the data collected from the fishery and urchin life history parameters derived from scientific studies, we conducted a formal stock assessment for the urchin stock. A stochastic observation-error length-structured model is used to describe the dynamics of the sea urchin population. A robust Bayesian approach is used for estimating fishery parameters because of concerns of possible outliers in fisheries data and mis-specification of priors. This study shows that the current stock is only 10% of the virgin stock biomass and that the exploitation rate is close to 40% suggesting that a large reduction in exploitation rate is necessary.     

Effect of dietary protein reduction with lysine and methionnine supplementation on growth performance,body composition and total ammonia nitrogen excretion of juvenile grass carp,Ctenopharyngodon idella

A 63‐day growth trial was undertaken to estimate the effects of supplemented lysine and methionine with different dietary protein levels on growth performance and feed utilization in Grass Carp (Ctenopharyngodon idella). Six plant‐based practical diets were prepared, and 32CP, 30CP and 28CP diets were formulated to contain 320 g kg^?1, 300 g kg^?1 and 280 g kg^?1 crude protein without lysine and methionine supplementation. In the supplementary group, lysine and methionine were added to formulate 32AA, 30AA and 28AA diets with 320 g kg^?1, 300 g kg^?1 and 280 g kg^?1 dietary crude protein, respectively, according to the whole body amino acid composition of Grass Carp. In the groups without lysine and methionine supplementation, weight gain (WG, %) and specific growth rate (SGR, % day^?1) of the fish fed 32CP diet were significantly higher than that of fish fed 30CP and 28CP diets, but no significant differences were found between 30CP‐ and 28CP‐diet treatments. WG and SGR of the fish fed 32AA and 30AA diets were significantly higher than that of fish fed 28AA diets, and the performance of grass carp was also significantly improved when fed diets with lysine and methionine supplementation (P < 0.05), and the interaction between dietary protein level and amino acid supplementation was noted between WG and SGR (P < 0.05). Feed intake (FI) was significantly increased with the increase in dietary protein level and the supplementation of lysine and methionine (P < 0.05), but feed conversion ratio (FCR) showed a significant decreasing trend (P < 0.05). Two days after total ammonia nitrogen (TAN) concentration test, the values of TAN discharged by the fish 8 h after feeding were 207.1, 187.5, 170.6, 157.3, 141.3 and 128.9 mg kg^?1 body weight for fish fed 32CP, 32AA, 30CP, 30AA, 28CP and 28AA diets, respectively. TAN excretion by grass carp was reduced in plant‐based practical diets with the increase in dietary protein level and the supplementation of lysine and methionine (P < 0.05). The results indicated that lysine and methionine supplementation to the plant protein sources‐based practical diets can improve growth performance and feed utilization of grass carp, and the dietary crude protein can be reduced from 320 g kg^?1 to 300 g kg^?1 through balancing amino acids profile. The positive effect was not observed at 280 g kg^?1 crude protein level.     

Effect of Chitosan on Intestinal Bacteria of Allogynogenetic Crucian Carp,Carassius auratus gibelio,as Depicted by polymerase chain reaction‐denaturing Gradient Gel Electrophoresis

A 16S rDNA‐based polymerase chain reaction‐denaturing gradient gel electrophoresis (PCR‐DGGE) method was applied to detect intestinal bacterial communities of juvenile allogynogenetic crucian carp, Carassius auratus gibelio, fed with chitosan‐containing diet. This is the first time to use the molecular method to analyze the bacterial communities in the allogynogenetic crucian carp intestine. The DGGE profile with universal bacterial primers revealed simple communities in all treatment groups. Sequencing and phylogenetic analysis of excised DGGE bands showed that the dominant bacteria belonged to class γ‐Proteobacteria and Fusobacteria. The relative abundance and diversity of detected bacteria suggested that 0.5 and 0.75% of chitosan in diet were optimum for juvenile allogynogenetic crucian carp. As in these concentrations, some detected pathogen bacteria either disappeared or decreased. However, the DGGE profile with Aeromonas‐specific primers showed a similar composition among all treatment groups, which suggested that Aeromonas was one of relative stable bacteria components in the intestine of juvenile allogynogenetic crucian carp.     

关于网箱养草对养殖水体的净化效果的探讨

近年来,由于缺乏生态环境保护意识,片面强调高产值和养殖规模的扩大,一些养殖池塘受污染的程度超过其自净能力,长期积累的负面效应引起生态系统的退化。轻者导致养殖效益下降,重者导致养殖对象的大批死亡。在本实验中,将异育银鲫和菹草混养在室外池塘中,建立鱼草共生系统。监测水体主要的理化因子的变化规律,测定异育银鲫的生长情况。从而探讨网箱养草对养殖水体主要营养盐的去除效果。试验结果表明:菹草具有明显的净化作用,可以有效的吸收TP和TN,增加水体DO,稳定水体,并能促进异育银鲫的生长。     

用酶联免疫吸附受体法检测鱼类生长激素的生物活性

根据激素一受体反应的原理，结合酶联免疫吸附测定法（ＥＬＩＳＡ）和放射受体测定法（ＲＲＡ）的优点，应用我们纯化的Ａ昌鱼生长激素（ｇｃＧＨ）和大鳞大马哈鱼生长激素（ｓＧＨ）及其特异抗体，采用鱼类肝细胞膜受体制剂，首次建立了测定鱼类ＧＨ生物活性的酶联免疫吸附受体测定法（ＥＬＩＳＡ－ＲＡ）。此法检测草鱼ＧＨ的灵敏度达０．０６３￣０．１２５ｕｇ／ｍｌ，检测大马哈鱼ＧＨ与草鱼肝膜受体结合的灵敏度达０．２５ｕｇ     

鲤鱼血清蛋白,血红蛋白,LDH和EST同工酶的电泳分析

采用聚丙烯酰胺凝胶电泳技术,分析了鲤鱼性成熟期雌雄个体的血清蛋白、血清脂蛋白和血红蛋白,结果是雌雄个体血清蛋白电泳图谱有差异,雌性(14条)比雄性(13条)多1条蛋白带;血清脂蛋白和血红蛋白无性别差异。同时,测定了鲤鱼血清、肝胰脏、心脏、背部肌肉和眼晶体的乳酸脱氢酶(LDH)同工酶和酯酶(EST)同工酶,LDH具有组织特异性,除在肝胰脏分离出9条酶带外,在血清中也分离出8条酶带,表明有LDH—c基因的作用,EST同工酶表现出明显的多态性,表明在鲤鱼各组织中有多个基因座位起作用。     

白斑综合证病毒胶体金免疫层析试剂板的研制

将胶体金免疫层析技术应用于对虾白斑综合征的诊断,研制了一种检测对虾中白斑综合征病毒的胶体金免疫层析试剂板.将胶体金标记的抗白斑综合征病毒单克隆抗体包被在金标垫上,将抗白斑综合征病毒多克隆抗体和羊抗鼠IgG分别包被在硝酸纤维素膜的检测线和质控线上.通过双抗体夹心法检测样品中自斑综合征病毒含量.结果表明,该试剂板对白斑综合征病毒的最低检出限为1.0 mg/kg,特异性好,稳定性高,整个检测所需时间为8～10 min,适合现场快速检测.     

全过程安全评估体系在浙江省水库型水源地的应用

国内的水源地评价主要是采用水质指标的单因子评价,缺乏考虑水源地环境质量、水生态系统状况的综合因子,不能有效识别水源地的安全状况。为此,本研究按照水源产生过程、蓄水过程分析的水污染环节和各种危害因素,从环境特征、人类活动、水质状况和生态完整性4个方面构建水源地全过程评估指标体系。并选择浙江省4座水库型水源地,开展全过程评估指标体系应用。评估结果表明:全过程评估体系较好地反映水源地水在不同阶段的安全状况,发现存在的问题,并能针对性地提出污染控制和预防改进措施,能够切实可行的运用于水库型水源地安全评估的实际工作,为水资源管理提供技术支撑。