梯级开发鱼类洄游通道恢复决策支持系统构建-以湘江干流梯级开发为例

河流梯级水电开发是我国在未来一段时间应对能源需求与结构问题的重要手段,如何缓解其对渔业资源的影响成为决策者不能回避的难题。本研究尝试将决策支持系统技术应用到这一领域,为鱼类洄游通道的恢复工作提供决策辅助。研究以湘江干流梯级开发为例,分析了梯级开发鱼类洄游通道恢复所面临的问题,构建了以空间基础数据库、决策模型库、知识库以及人机交互平台为基础的湘江干流鱼类洄游通道恢复决策支持系统。系统通过对湘江干流梯级开发的辅助决策,展现了良好的实用性。     

长江中游江湖生物通道恢复的关键生物学问题与框架构建——以武汉市涨渡湖群为例

围绕生物通道恢复面临的科学、技术问题进行方案设计与分析,搭建生物通道恢复技术框架,为推动长江中下游江湖生态保护和修复工作提供技术思路与借鉴参考。以涨渡湖群为研究试点,系统总结了该水域江湖洄游鱼类在“长江-湖泊”的迁徙、洄游规律,掌握鱼类入湖和出湖习性。围绕幼鱼入湖、成鱼入湖与出湖等不同生活史阶段的需求,结合河湖水位变化特征与影响、现有工程及调度措施的局限性,提出了“季节性灌江纳苗”“生态水网+过鱼设施”及调度运行等方案,从保障江湖洄游性鱼类生活史完成的角度搭建生物通道恢复框架。工程建设、综合调度和管理措施旨在解决江湖复合生态系统江湖阻隔问题,以达到洄游鱼类及生物多样性恢复、河湖水生生境修复的目标。     

论恢复鱼类洄游通道规划方法

由于鱼类洄游是大尺度的水生动物迁徙运动,恢复鱼类洄游通道规划应在流域尺度进行。本文讨论了恢复鱼类洄游通道规划要点,包括河流鱼类调查及评价方法、规划范围和流域恢复洄游通道目标量化方法,提出了恢复鱼类洄游鱼类通道项目的优先排序方法,并以保护和恢复多瑙河鲟鱼规划作为典型案例进行了分析。恢复鱼类洄游鱼类通道项目的优先排序方法中,应根据工程性质、特点和当地自然条件确定优先排序准则,从而选择重点河段和重点工程,解决洄游通道中的关键问题。优先排序准则包括有效性、栖息地适宜性、效益/投资分析、自然保护区范围、预期物种多样性、鱼类生产力和栖息地面积等。在保护和恢复多瑙河鲟鱼规划案例中,确定了多瑙河鱼类洄游障碍物的5个等级划分标准和评分等级,采用改进的多准则多权重分级计分法计算了各障碍物的排序指标。在671处障碍物中,29处为最优先排序,99处为中等排序,543处为低等级排序。其中,位于多瑙河中游和下游的铁门水电站Ⅰ、Ⅱ级是流域内的主要障碍物。优先级排序方法为恢复鱼类洄游通道提供了指导意见。     

长江流域鱼类洄游通道恢复对策研究

论述了鱼类洄游通道恢复的理论基础,我国鱼类洄游通道恢复的历史和现状,并分析了长江流域鱼类洄游通道阻隔现状及其对鱼类资源的影响。在此基础上提出了长江流域鱼类洄游通道恢复的对策:制定鱼类洄游通道恢复规划;建立鱼类洄游通道恢复的相关法律体系和协调机制;开展鱼类洄游通道恢复关键技术研究;加强鱼类洄游通道恢复研究能力建设,建立科学的技术支撑体系。     

鱼类洄游中的能量变化研究进展

1鱼类洄游的定义和分类洄游是部分鱼类生活史中的重要行为之一,通常指鱼类在育幼场、觅食场和产卵场之间主动、定向和周期性的迁移[1]。按已有的定义,洄游应当是持续的定向运动[2],因此McCormick等[3]提出,多数鱼类的洄游实际应为"移动"。洄游对鱼类获取     

葛州坝水利枢纽对长江鱼类资源的影响及该枢纽过鱼对象的建议

葛州坝水利枢纽的修建，截断了长江鱼类洄游的通道，将对鱼类资源产生一定的影响。多年来，由于对该工程可能造成影响的程度，未能取得统一的认识，因此在枢纽上是否需要保留鱼类的通道和给那些鱼类保留通道，一直存在一些分歧意见。     

鱼类的洄游及影响鱼类洄游的因素和研究方法

一、洄游的类型依据洄游的主要动力,可以划分为被动洄游与主动洄游。被动洄游是指鱼类随水流而移动,在移动中本身不消耗或消耗很少的能量。主动洄游则是鱼类主要依靠自身的运动能力所进行的洄游。此外根据鱼类在洄游时所处     

国外解决水工建筑物阻隔洄游性鱼类上溯通道的技术措施和发展趋向

国外洄游性鱼类(鲑、鳟、鳗、鲟等)经济价值较高。他们都按一定的规律在河海之间洄游、繁殖、生长。在河流中修建水利枢纽就会截断这些鱼类的洄游通道而造成严重减产，甚至绝迹。下面简单介绍美国、加拿大、苏联、日本等国解决这个问题的技术措施和发展趋向。     

草鱼洄游适宜流速条件与适应阈值

洄游通道的连通性及其水文条件,是制约鱼类正常洄游和产卵繁殖的关键因素,现有的生态流量相关研究更多侧重于产卵场栖息地模拟,忽略了鱼类洄游水流条件的重要性。为了探究流速条件对鱼类洄游上溯的影响,选取体长(55±5)cm的草鱼(Ctenopharyngodon idellus)为实验对象,通过搭建鱼类洄游仿真河道,营造不同的流速工况,观察不同情景方案下实验鱼群上溯洄游情况,并利用模糊逻辑法对鱼类上溯洄游率、平均上溯时间及上溯持续性等实验参数进行综合分析,探索草鱼洄游的适宜流速条件与适应阈值。结果显示,在流速0.20m/s以下时,草鱼基本无上溯行为;流速0.25～0.80m/s,70%样本在15min内完成上溯,但0.25～0.30m/s时,鱼群上溯缺乏明显的持续性;0.90～1.00m/s时,80%以上样本在5min快速完成上溯;流速超过1.1m/s时,上溯成功率明显降低。研究表明,实验草鱼洄游的适宜流速范围是0.40～1.00m/s,而刺激草鱼洄游的最小流速阈值是0.20m/s。相关结果可为河流生态水力学模拟和河流生态修复以及水利工程生态调度提供技术支撑。     

鄱阳湖通长江水道洄游鱼类及影响因素分析

通长江水道是一些河海洄游性、江湖洄游性鱼类进行长江与鄱阳湖之间洄游的必经水域。近年来,由于围湖造田、过度捕捞、开挖湖沙、拦河筑坝等人类活动的影响,鄱阳湖的生态环境和渔业功能日渐恶化。为了解鄱阳湖洄游鱼类资源的种群变化,本文对洄游鱼类种类、群落结构及其影响因素进行了概述。     

Rare serotype occurrence and PFGE genotypic diversity of Streptococcus agalactiae isolated from tilapia in China

Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China.     

Growth hormone (GH) and reproduction: a review

Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations.     

Purification and partial characterization of GtHs (cfLH and cfFSH) from Indian walking catfish (Clarias batrachus) (L.) and development of a homologous ELISA for cfLH

Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL^?1 (1.25 ng well^?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation.     

Controlled infection of Poecilia reticulata Peters (guppy) with Tetrahymena by immersion and intraperitoneal injection

Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg^?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality).     

Imported ornamental fish are colonized with antibiotic‐resistant bacteria

There has been growing concern about the overuse of antibiotics in the ornamental fish industry and its possible effect on the increasing drug resistance in both commensal and pathogenic organisms in these fish. The aim of this study was to carry out an assessment of the diversity of bacteria, including pathogens, in ornamental fish species imported into North America and to assess their antibiotic resistance. Kidney samples were collected from 32 freshwater ornamental fish of various species, which arrived to an importing facility in Portland, Oregon from Colombia, Singapore and Florida. Sixty‐four unique bacterial colonies were isolated and identified by PCR using bacterial 16S primers and DNA sequencing. Multiple isolates were identified as bacteria with potential to cause disease in both fish and humans. The antibiotic resistance profile of each isolate was performed for nine different antibiotics. Among them, cefotaxime (16% resistance among isolates) was the antibiotic associated with more activity, while the least active was tetracycline (77% resistant). Knowing information about the diversity of bacteria in imported ornamental fish, as well as the resistance profiles for the bacteria will be useful in more effectively treating clinical infected fish, and also potential zoonoses in the future.     

Effect of iodophor disinfection of non‐hardened Salmo trutta eggs on their bacterial and fungus load

This study investigated the efficiency of iodophor disinfection (135 ppm active iodine for 15–30 min) of non‐hardened Salmo trutta eggs against different groups of bacteria and against fungus. Egg samples were taken from non‐disinfected and from disinfected eggs, microorganisms were cultured on specific nutrient media and their mass was measured by turbidimetric methods. Bacteria and fungus mass of non‐hardened eggs could be reduced but not eliminated by iodophor disinfection with 135 ppm active iodine for 15 min. The extent of reduction was 47–65% (Experiment 1). The efficiency of disinfection increased with disinfection time as the reduction in bacteria and fungus mass was 40–55% after 15 min and 58–74% after 30 min (Experiment 2). Disinfection efficiency of iodophor solution diluted in water (reduction 49–57%) and of iodophor solution diluted in sodium chloride solution iso‐osmolar to the oocytes (reduction 52–61%) was similar (Experiment 3). The reduction in bacteria and fungus mass was persistent as it was 39–72% lower in embryos deriving from disinfected eggs than in embryos deriving from non‐disinfected ones (Experiment 4). In conclusion, the tested disinfection method is inadequate to eliminate pathogens completely but it could positively influence immune defence of eggs and embryos.     

Nitrogenous waste excretion and accumulation of urea and ammonia inChalcalburnus tarichi (Cyprinidae), endemic to the extremely alkaline Lake Van (Eastern Turkey)

The endemic, anadromous cyprinidChalcalburnus tarichi is the only fish species known to occur in alkaline Lake Van (Eastern Anatolia, Turkey). EightC. tarichi were maintained individually in Lake Van water (17 – 19°C; pH 9.8; 153 mEq·I^–1 total alkalinity; 22 total salinity) and tank water samples analyzed for 24 h in 2 to 4 h intervals. At zero time, < 1µM ammonia was present and urea was undetectable in the tank water; at 24 h, total ammonia and urea made up 114±32 and 35±25µM, respectively. Over the experimental period, ammonia-N and urea-N excretion averaged 1041±494 and 607±169moles·kg^–1 fish·h^–1, respectively. The extent of urea excretion was highly variable between specimens. Uric acid excretion was not detectable.Urea was present at high concentrations in all tissues and plasma (25 – 35moles·g^–1·ml^–1) of freshly caughtC. tarichi; total ammonia content of the tissues was by a factor of 1.9 (liver) to 3.0 (brain) lower. High arginase activity (2.4±0.2 U·min^–1·g^–1) was detected in the liver ofC. tarichi but ornithine carbamoylphosphate transferase, a key enzyme of the ornithine-urea-cycle, was absent. Ureagenesis is likely through degradation of arginine and/or uricolysis. High glutamine synthetase activity (11±0.6 U·min^–1·g^–1) and low ammonia content in brain suggest that, like other teleosts,C. tarichi has an efficient ammonia detoxification in the brain, but in no other tissue.Nitrogenous waste excretion at alkaline pH is discussed. The ability ofC. tarichi to excrete high levels of ammonia at extremely alkaline pH is unique among teleosts studied so far. The mechanism of ammonia excretion under Lake Van conditions remains to be elucidated.     

Influence of the antibacterial herbs, Solanum trilobatum, Andrographis paniculata and Psoralea corylifolia on the survival, growth and bacterial load of Penaeus monodon post larvae

The indiscriminate use of antibiotics and chemicals in shrimp hatcheries has led to biomagnification and that in turn could lead to rejection of a whole consignment. The application of the bioencapsulation technique as a tool for curative treatment in shrimp larvae was investigated. Herbs having antibacterial properties such as Solanum trilobatum, Andrographis paniculata and Psoralea corylifolia (methanolic extracts) were bioencapsulated in Artemia and fed to Penaeus monodon post larvae PL 1–25. The post larvae were reared in a medium inoculated with pathogenic bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhi and Vibrio sp. Post larvae reared in the non-inoculated water and fed with non-enriched Artemia exhibited 90% survival, highest specific growth rate (12.43%) and reduced bacterial load. P. monodon reared in the bacterial inoculated water and fed with the non-enriched Artemia exhibited the lowest survival (10–30%), specific growth rate (8.42–9.1%) and increased bacterial load (2.86 × 10³ to 3.76 × 10⁵ cfu/g). The methanolic extracts of the herbs helped to increase survival and specific growth rate and reduced bacterial load in the P. monodon culture system. Among the three herbal extracts, P. corylifolia enriched Artemia fed post larvae showed the tendency to higher survival (>50%), growth rate (11.5 averaged) and low bacterial load (1.12 × 10⁵ cfu/g). This revised version was published online in August 2006 with corrections to the Cover Date.