20万尾花斑裸鲤放流黄河源甘德段

<正>本刊讯7月5日,三江源生态保护基金会、青海省精神文明建设指导办公室、青海省农牧厅、果洛州人民政府在果洛藏族自治州联合举办"2014年青海省黄河土著鱼类增殖放流活动",20万尾体长10cm的花斑裸鲤放流甘德段(夏日乎寺)。200多名农牧民群众、寺院僧众及干部职工参加。2007年以来,青海水产技术推广站和黄河上游水电开发有限责任公司建设公司合作,建成第一座黄河苏只和积石峡鱼类增殖站,开始了花斑裸鲤等黄河上游土著鱼类的人工繁育试验研究工作,在野生土著鱼类亲鱼的捕捞、运输、人工驯养、规模化人工繁殖和苗种培育等     

基于生长参数及产量方程的鱼类放流效益调查估算

为量化评估增殖放流鱼类产生的经济效益和生态价值,根据广西2013年度中央财政渔业资源保护项目增殖放流鱼类的品种、规格、数量,利用鱼类的生长特征参数、自然死亡系数和捕捞死亡系数,通过巴拉诺夫产量方程估算增殖放流鱼类的回捕量以及水生生物营养转换传递参数、成本参数和市场价格。结果显示,该项目增殖放流鱼类回捕的直接经济效益为10 293万元,投入产出比为1∶25;回捕的放流鱼类从水域中提取氮127.9 t,磷25.6 t,碳汇输出1 874.5 t;回捕放流鱼类及存留鱼类共消耗水域底栖动物44 327.2 t;年度放流总生态价值5 775万元。调查结果表明,开展鱼类增殖放流能产生较好的渔业经济效益和生态效益,有利于维护渔业生态环境健康。     

2015黄河土著鱼类增殖放流活动青海达日县举行

<正>本刊讯(李明爽报道)8月8日,2015年黄河土著鱼类增殖放流暨首届玛域达日·黄河谷地观景节活动在青海省果洛州达日县举行,32万尾平均体长超过5cm的花斑裸鲤苗种放入黄河达日段。本次放流活动有青海省农牧厅、果洛州人民政府主办,青海省渔业环境监测站、果洛州农牧局、达日县人民政府和达日县吉迈镇人民政府协办。     

2011年黄河鱼类增殖放流活动在青海贵德举行

本刊讯（特约记者 关弘弢 报道）8月16日，2011年青海黄河鱼类增殖放流活动在青海贵德举行，活动共向黄河放流经过标记的花斑裸鲤、极边扁咽齿鱼等土著鱼类鱼苗80万尾。本次活动由省农牧厅和贵德县人民政府联合主办，青海省渔业环境监测站承办。     

安徽徽水河渔业增殖放流对鱼类资源分布状况及修复力影响的研究

正徽水河属长江流域三级支流,由众多山区溪流性水域汇集而成,历史上水生生物资源富足,品种繁多,是山区特色水生生物的自然储存库,具有优越的自然环境。但由于各种原因,该水域段的水生生物资源量急剧下降,部分资源面临危机。为改善水域环境和水生生物资源状况,当地渔业部门在建立徽水河特有鱼类国家级水产种质资源保护区的基础上,对重点水域连续多年开展渔业增殖放流活动。2019年,当地渔业部门在开展徽水河渔业增殖放流的同时,对鱼类资源分布状况进行全面调查研究,充分分析了放流效果,为后期开展物种保护提供理论数据和研究基础。     

《关于进一步规范长江流域水生生物增殖放流工作的通知》印发

正本刊讯水水生生物增殖放流是坚持渔业绿色发展的有效手段,是水生生物资源保护的重要举措,是水域生态修复的具体抓手,得到了社会各界的广泛关注和大力支持,产生了良好的生态、社会和经济效益。为贯彻习近平生态文明思想,落实《国务院办公厅关于加强长江水生生物保护工作的意见》决策部署,加大资源保护力度,统筹增殖放流规划布局、保障苗种质量、规范放流行为、科学监测评估、严格执法监管,不断提升增殖     

三峡库区万县段渔业资源调查及保护增殖措施

根据三峡库区万县段渔业生态环境条件及渔获物分析，提出了选择合理渔法，限制网目规格，建立禁渔区，禁渔期，治理渔业水域污染，建立人工放流站和加强渔业行政执法等渔业资源的保护与增殖措施。     

我国海草场保护与恢复对策建议

为全面贯彻实施国务院颁布的《中国水生生物资源养护行动纲要》,我国各级渔业部门严格执行禁渔区和禁渔期制度、积极开展自然保护区建设和管理、水生生物资源增殖放流和海洋牧场建设等多项渔业生态保护工作。作为海洋牧场建设中的重要组成部分,海草场的恢复工作业已被各级渔业行政主管部门提上日程。     

水生生物增殖放流管理规定

<正>水生生物增殖放流,是指采用放流、底播、移植等人工方式向海洋、江河、湖泊、水库等公共水域投放亲体、苗种等活体水生生物的活动。主管部门及职责农业部主管全国水生生物增殖放流工作。县级以上地方人民政府渔业行政主管部门负责本行政区域内水生生物增殖放流的组织、协调与监督管理。各级渔业行政主管部门应当加大对水生生物增殖放流的投入,积极引导、鼓励社会资金支持水生生物资源养护和增殖放流事业。县级以上地方人民政府渔业行     

加强长江水生生物多样性保护的若干思考

长江是世界上著名的生物多样性热点地区，是重要的物种基因库和天然的资源活体库，对维系我国水域生态平衡、保障生态安全和经济社会可持续发展具有极为重要的作用。在各种人类活动的影响下，长江水生生物资源严重衰退，鱼类完整性达到了“无鱼”的级别。2021年起，国家开始全面实施长江十年禁渔，现已初见成效。但是，水电开发、水污染、江湖阻隔造成的栖息地退化等问题依旧严重。本文综合评估了长江水生生物多样性现状和已有的保护措施，认为生境破坏、水质恶化、外来种入侵、科研和保护工作投入不足，是目前长江水生生物多样性保护中存在的主要问题。在十年禁渔实施的新形势下，为了修复长江水域的生态环境和保护水生生物资源，提出了加强长江水生生物多样性保护的若干建议，包括加强珍稀鱼类的人工保育，转换鱼类人工增殖放流目标；加强水生态修复的技术研究与项目实施；加强生态观测站和水生生物战略资源库建设；加大保护研究的投入；完善长江禁捕水域科研监测的审批和管理制度，健全长江水生生物保护管理体系等。     

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.     

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).     

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.     

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.     

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.     

Effects of cortisol on hepatic carbohydrate metabolism and responsiveness to hormones in the sea raven,Hemitripterus americanus

The sea raven, Hemitripterus americanus, is a sit-and-wait, low metabolic rate, marine teleost. The objective of this study was to determine i) whether cortisol implantation (50 mg. kg^-1) for 7 days altered hepatocyte metabolism, and hepatocyte responsiveness to epinephrine, glucagon and insulin, and ii) whether 8 weeks of food-deprivation modified the above response. Cortisol implantation significantly increased hepatocyte total glucose production and oxidation from alanine compared to the sham group. There was no cortisol effect on glycogen breakdown, suggesting that the activation of other pathways, including gluconeogenesis, are required to account for the increased glucose production. Epinephrine-mediated (10^-5M) glycogen breakdown and insulin-mediated (10^-8M) total glucose production were enhanced in hepatocytes of cortisol implanted sea ravens, but there were no change in any glucagon (10^-7M) effects. The enhanced glycogen breakdown in the absence of similar increases in total glucose production with epinephrine indicates mobilization of carbohydrate reserves for endogenous use by the liver. Food-deprivation for 8 weeks significantly decreased condition factor, plasma cortisol concentration and liver glycogen content in the sea raven, but had no effect on plasma glucose concentration. Hepatocyte total glucose production and flux rates from alanine increased significantly with food-deprivation. Moreover, food-deprivation increased responsiveness of total hepatocyte glucose production to the actions of glucagon and insulin, but not to epinephrine; none of these effects were modified by cortisol implantation. Our results indicate that cortisol in the sea raven exerts both a direct and an indirect or permissive effect on hepatocyte metabolism by modifying hepatocyte responsiveness to epinephrine and insulin stimulation. Cortisol implantation did not modify the effects of glucagon or food-deprivation in this species.     

Simulation and quantification of enrichment and retention processes in the southern Benguela upwelling ecosystem

Important environmental processes for the survival and recruitment of early life stages of pelagic fishes have been synthesized through Bakun's fundamental triad as enrichment, concentration and retention processes (A. Bakun, 1996, Patterns in the Ocean. Ocean Processes and Marine Population Dynamics. San Diego, CA, USA: University of California Sea Grant). This conceptual framework states that from favourable spawning habitats, eggs and larvae would be transported to and/or retained in places where food originating from enrichment areas would be concentrated. We propose a method for quantifying two of the triad processes, enrichment and retention, based on the Lagrangian tracking of particles transported within water velocity fields generated by a three‐dimensional hydrodynamic model. We apply this method to the southern Benguela upwelling ecosystem, constructing putative maps of enrichment and retention. We comment on these maps regarding main features of the circulation in the region, and investigate seasonal variability of the processes. We finally discuss the results in relation to available knowledge on the reproductive strategies of two pelagic clupeoid species abundant in the southern Benguela, anchovy (Engraulis encrasicolus) and sardine (Sardinops sagax). Our approach is intended to be sufficiently generic so as to allow its application to other upwelling systems.     

Antimicrobial activity of the biopolymer chitosan against Streptococcus iniae

The antimicrobial activity and mode of action of chitosan were evaluated against Streptococcus iniae, a pathogenic Gram‐positive bacterium of fish worldwide. Cell proliferation kinetics were examined following exposure to varying concentrations of chitosan. The action of chitosan on S. iniae was also investigated by measuring agglutination activity, conductivity, and extracellular and intracellular bacterial adenosine triphosphate (ATP) levels. Chitosan exhibited antibacterial activity against S. iniae at concentrations of 0.1% and above and was lethal at a concentration of 0.4% and higher. The mechanism of antibacterial activity of chitosan at the inhibitory level of bacterial growth appears to hinge upon the interaction between chitosan and the oppositely charged bacterial surface. This interplay causes agglutination, which was readily observed grossly and microscopically. After interacting with the cell surface via adsorption, an efflux of intracellular ATP was documented, which suggests that chitosan disrupts the bacterial cell causing leakage of cytosolic contents and ultimately cell death. Results suggest chitosan may be worth evaluating as a natural alternative to antibiotic against S. iniae infection of fish.     

The effects of introduced tilapias on native biodiversity

• 1. The common name ‘tilapia’ refers to a group of tropical freshwater fish in the family Cichlidae (Oreochromis, Tilapia, and Sarotherodon spp.) that are indigenous to Africa and the southwestern Middle East. Since the 1930s, tilapias have been intentionally dispersed worldwide for the biological control of aquatic weeds and insects, as baitfish for certain capture fisheries, for aquaria, and as a food fish. They have most recently been promoted as an important source of protein that could provide food security for developing countries without the environmental problems associated with terrestrial agriculture. In addition, market demand for tilapia in developed countries such as the United States is growing rapidly.
• 2. Tilapias are well‐suited to aquaculture because they are highly prolific and tolerant to a range of environmental conditions. They have come to be known as the ‘aquatic chicken’ because of their potential as an affordable, high‐yield source of protein that can be easily raised in a range of environments — from subsistence or ‘backyard’ units to intensive fish hatcheries. In some countries, particularly in Asia, nearly all of the introduced tilapias produced are consumed domestically; tilapias have contributed to basic food security for such societies.
• 3. This review indicates that tilapia species are highly invasive and exist under feral conditions in every nation in which they have been cultured or introduced. Thus, the authors have concluded that, despite potential or observed benefits to human society, tilapia aquaculture and open‐water introductions cannot continue unchecked without further exacerbating damage to native fish species and biodiversity. Recommendations include restricting tilapia culture to carefully managed, contained ponds, although exclusion is preferred when it is feasible. Research into culture of indigenous species is also recommended.

Copyright © 2005 John Wiley & Sons, Ltd.