The effect of meal size on the rate of gastric evacuation of burbot, Lota lota (L.)

Abstract– The effect of meal size on the gastric evacuation rate of burbot Lota lota (L.), was determined at a constant temperature of 1.5°C. Burbot were fed vendace Coregonus albula (L.), in varying amounts from 1.0% to 12.6% of burbot weight. Although gastric evacuation rate decreased exponentially with increasing meal size, the absolute amount of food evacuated per day (g. day⁻¹ increased when meal size increased. The estimated maximum daily gastric evacuation rates were 0.8, 1.3 and 1.6 g/day with meal sizes 1%, 5% and 10% of burbot weight (200 g). No difference in gastric evacuation rate was observed between meals of the same size (8 g) but which consisted of either one or three vendace.     

Recruitment of burbot (Lota lota L.) in Lake Erie: an empirical modelling approach

Stapanian MA, Witzel LD, Cook A. Recruitment of burbot (Lota lota L.) in Lake Erie: an empirical modelling approach.
Ecology of Freshwater Fish 2010: 19: 326–337. Published 2010. This article is a US Government work and is in the public domain in the USA Abstract – World‐wide, many burbot Lota lota (L.) populations have been extirpated or are otherwise in need of conservation measures. By contrast, burbot made a dramatic recovery in Lake Erie during 1993–2001 but declined during 2002–2007, due in part to a sharp decrease in recruitment. We used Akaike’s Information Criterion to evaluate 129 linear regression models that included all combinations of one to seven ecological indices as predictors of burbot recruitment. Two models were substantially supported by the data: (i) the number of days in which water temperatures were within optimal ranges for burbot spawning and development combined with biomass of yearling and older (YAO) yellow perch Perca flavescens (Mitchill); and (ii) biomass of YAO yellow perch. Warmer winter water temperatures and increases in yellow perch biomass were associated with decreases in burbot recruitment. Continued warm winter water temperatures could result in declines in burbot recruitment, particularly in the southern part of the species’ range.     

Characterization of susceptibility and carrier status of burbot,Lota lota (L.), to IHNV,IPNV, Flavobacterium psychrophilum,Aeromonas salmonicida and Renibacterium salmoninarum

In this study, susceptibility and potential carrier status of burbot, Lota lota, were assessed for five important fish pathogens. Burbot demonstrated susceptibility and elevated mortality following challenge with infectious haematopoietic necrosis virus (IHNV) by immersion and to Aeromonas salmonicida by intraperitoneal (i.p.) injection. IHNV persisted in fish for at least 28 days, whereas A. salmonicida was not re-isolated beyond 17 days post-challenge. In contrast, burbot appeared refractory to Flavobacterium psychrophilum following intramuscular (i.m.) injection and to infectious pancreatic necrosis virus (IPNV) by immersion. However, i.p injection of IPNV resulted in re-isolation of virus from fish for the duration of the 28 day challenge. Renibacterium salmoninarum appeared to induce an asymptomatic carrier state in burbot following i.p. injection, but overt manifestation of disease was not apparent. Viable bacteria persisted in fish for at least 41 days, and bacterial DNA isolated by diagnostic polymerase chain reaction was detected from burbot kidney tissue 90 days after initial exposure. This study is the first to investigate susceptibility of burbot to selected fish pathogens, and this information will aid in efforts to culture and manage this species.     

Effects of biological,economic and management factors on tuna and billfish stock status

Commercial tunas and billfishes (swordfish, marlins and sailfish) provide considerable catches and income in both developed and developing countries. These stocks vary in status from lightly exploited to rebuilding to severely depleted. Previous studies suggested that this variability could result from differences in life‐history characteristics and economic incentives, but differences in exploitation histories and management measures also have a strong effect on current stock status. Although the status (biomass and fishing mortality rate) of major tuna and billfish stocks is well documented, the effect of these diverse factors on current stock status and the effect of management measures in rebuilding stocks have not been analysed at the global level. Here, we show that, particularly for tunas, stocks were more depleted if they had high commercial value, were long‐lived species, had small pre‐fishing biomass and were subject to intense fishing pressure for a long time. In addition, implementing and enforcing total allowable catches (TACs) had the strongest positive influence on rebuilding overfished tuna and billfish stocks. Other control rules such as minimum size regulations or seasonal closures were also important in reducing fishing pressure, but stocks under TAC implementations showed the fastest increase of biomass. Lessons learned from this study can be applied in managing large industrial fisheries around the world. In particular, tuna regional fisheries management organizations should consider the relative effectiveness of management measures observed in this study for rebuilding depleted large pelagic stocks.     

Quantification of the invasiveness risk of non-native macroalgae in the Azores to support conservation measures

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渔业资源增殖放流的生态风险及其防控措施

渔业资源增殖放流作为国内外水生生物资源养护领域普遍采用的一种做法, 其在提升增殖种类资源量的同时, 也会给野生资源种类和增殖水域生态系统健康带来诸多生态风险。现阶段, 系统评价增殖放流的生态风险、实施有效的生态风险防控已成为构建负责任增殖放流模式的必然要求。本文从种群、群落和生态系统3个层面系统评述国内外渔业资源增殖放流生态风险研究领域的最新进展, 阐述相应的生态风险防控措施, 以期为我国渔业资源增殖放流的生态风险防控工作提供理论参考。

     

闽南、台湾浅滩渔场灯光围网渔业状况分析

根据福建省1987～2003年闽南、台湾浅滩渔场(116°00′～119°30′E,22°00′～24°30′N)灯光围网作业生产统计数据和资源监测资料,分析研究了福建省在该渔场灯光围网作业状况、发展演变和资源利用现状。结果表明:由于单拖作业和流刺网作业的发展,灯光围网作业持续萎缩,在海洋渔业中的地位不断下降;渔船大型化,渔场向深水推进,灯源配置及集鱼并灯技术取得重大突破;主要渔获物中蓝圆鲹占绝对优势,鲐鱼所占比例有上升的趋势,金色小沙丁鱼年间波动明显,颌圆鲹则快速减少,竹鱼近年来产量快速增长。文章还提出改进和提高灯光围网作业捕捞技术和自身竞争力,合理引导部分疏目快拖作业参与中上层鱼类资源的开发利用等优化海区捕捞作业结构、合理开发利用海区渔业资源的管理建议。     

Fisheries and conservation assessment of sharks in Pacific Panama

1. In Panama, shark fisheries were initially developed in the 1980s and progressively increased in production in the 1990s mainly due to the high demand for shark fins and meat from the international Asian market. Since then, and despite the exploitation rate (average 3,514 t year^–1) and endangered status of some species, shark fisheries have seldom been studied, and official statistics are general or incomplete and not suitable for the development of appropriate conservation and management strategies.
2. To understand the dynamics of shark fisheries in Panama, field surveys were conducted between 2007 and 2009 at several landing ports of small‐scale and industrial fisheries, at fish processing plants and on‐board fishing vessels in Pacific Panama, where most of the fishing vessels of the country operate.
3. In general, it was found that the artisanal and industrial fisheries of the Pacific coast of Panama regularly exploit at least 18 species of sharks, which are also being exploited by neighbouring countries in the eastern Pacific, suggesting the importance of coordinated conservation initiatives across the multiple jurisdictions. A large number of the individuals caught were immature, implying a certain level of impact on recruitment rates. This pattern was particularly evident in species such as Sphyrna lewini, for which immature individuals represented at least 99% and 63% of the total catch by small‐scale and industrial fisheries, respectively. Catch per unit of effort analyses showed that Carcharhinus and Sphyrna species were the most exploited (representing ~80% of the catches) by industrial fisheries in Panama between 2006 and 2009, suggesting that fishery management should provide special attention to these groups.
4. It is expected that the information presented here provides a baseline to develop new regulations, including the implementation of annual quotas and fishing seasons and the protection of nursery areas, for the long‐term sustainability and conservation of sharks in Panama.

     

水电开发背景下长江上游保护区珍稀特有鱼类保护实践

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Complex influences of low-head dams and artificial wetlands on fishes in a Colorado River tributary system

Abstract  Low-head dams in arid regions restrict fish movement and create novel habitats that have complex effects on fish assemblages. The influence of low-head dams and artificial wetlands on fishes in Muddy Creek, a tributary of the Colorado River system in the USA was examined. Upstream, fish assemblages were dominated by native species including two species of conservation concern, bluehead sucker, Catostomus discobolus Cope, and roundtail chub, Gila robusta Baird and Girard. The artificial wetlands contained almost exclusively non-native fathead minnow, Pimephales promelas Rafinesque, and white sucker, Catostomus commersonii (Lacepède). Downstream, fish assemblages were dominated by non-native species. Upstream spawning migrations by non-native white suckers were blocked by dams associated with the wetlands. However, the wetlands do not provide habitat for native fishes and likely inhibit fish movement. The wetlands appear to be a source habitat for non-native fishes and a sink habitat for native fishes. Two non-native species, sand shiner, Notropis stramineus (Cope), and redside shiner, Richardsonius balteatus (Richardson), were present only downstream of the wetlands, suggesting a beneficial role of the wetlands in preventing upstream colonisation by non-native fishes.     

Genetic diversity and population structure of burbot Lota lota in Germany: Implications for conservation and management

The genetic structure of the gadiform fish species, burbot Lota lota L., was investigated across Germany to derive management options for facilitating the preservation of genetic diversity. Sequence analysis of the mitochondrial control region (n = 244) and microsatellite analysis (n = 861) of specimens from 20 sites revealed genetic structuring between major river basins, and particularly between lake and river habitats. The admixture zone between the Eurasian and West European phylogenetic clades in Lake Constance was confirmed and expanded to include the drainage basins of the rivers Rhine and Schlei/Trave. Haplotype distribution and private haplotypes in single river basins indicated population differentiation and imply that German burbot constituted an important part of the entire species' diversity. The derived genetic structuring has implications for future stocking programmes and the preservation of the adaptive potential of burbot, a guiding species for oligotrophic lakes in Europe.     

我国渔船用通信导航设备技术与质量现状

阐述了我国渔用无线电话机和渔用GPS导航仪目前的产品技术现状和存在的质量问题,并作思考和分析,对今后的技术发展提出了见解.     

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对上海市浦东新区渔业结构调整情况、渔业经济效益、渔业组织化水平和渔业技术水平等进行了概述,基于浦东新区渔业产业发展现状和产业布局情况,指出可养水面总体不足、养殖面积逐年减少、养殖效益低、渔业组织化程度较低、养殖病害频发、市场信息服务缺位等问题,以及从生产到市场销售整个产业链中存在的环节问题,并就浦东新区水产养殖绿色发展提出了相关对策和建议,可为浦东新区因地制宜提升渔业发展水平提供参考。     

我国水生生物增殖放流物种选择发展现状、存在问题及对策

增殖放流是一项复杂的系统工程,合理规划放流物种是增殖放流工作开展的核心。为促进增殖放流工作科学、规范、有序开展,根据我国增殖放流工作的制度规范和相关要求,就增殖放流物种选择发展现状和存在问题进行了全面总结,包括放流物种的种质来源、优先选择层级、功能定位匹配以及放流公益属性等,提出了增殖放流物种选择需要注意的相关原则以及对策建议,以期为我国增殖放流工作开展提供参考。     

福建莆田近海鲻鱼渔业现状及秋冬季产卵群体特点

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辽宁省葠窝水库水质现状与渔业性能评价

近年来,葠窝水库流域综合管理提高了水库水质状况,为了给下一步的渔业生产提供科学依据,在2008-2009年对葠窝水库6个代表性断面进行了4次采样调查和实验室分析,并采用水质综合评价方法对葠窝水库水质进行评价。检测结果表明水质状况总体有所好转,主要污染物为非离子氨和重金属铜,其他指标正常。采用流域综合水质指数法对水库总体水质状况进行评价,水库水质指数为4.33,为Ⅳ类水质;综合考虑水库理化特征、库龄和形态等,评价葠窝水库属中营养类型。通过对葠窝水库进行渔业水质分析发现,库区大部分地区符合水产养殖基本要求,建议在局部科学发展渔业生产。     

Linking pipefishes and seahorses to seagrass meadows in the Venice lagoon: Implications for conservation

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泉州市淡水水产养殖业发展状况及对策

泉州市2007年的淡水水产养殖面积为6180hm2,总产量14253 t,虽然2007年的养殖面积比1995年降低11.9%,但总产量还是比1995年增加了6644 t,增长了87.3%。该市近年来的淡水水产养殖产量有了一定的发展,但也存在着养殖品种结构未能多样化、渔业产业化水平不高、苗种繁育设施薄弱、局部养殖水域环境污染及养殖规划滞后等问题。为确保该市淡水水产养殖业的可持续发展,必须在科学合理利用水域生物资源的同时,以资源为依托,以科教兴渔、依法兴渔为手段,注重挖潜与开发并举,产量与质量并重,常规与特养并行;并以提高产品质量、增加效益为重点,抓好淡水水产良种的引进、繁育、推广及改革养殖模式;应尽快实施和落实"内陆水域水产养殖规划",发展区域特色渔业,延伸产业链,努力推进淡水渔业产业化进程。     

我国渔业产品质量安全管理机制的构建与完善

当前,食品质量安全问题已经引起了包括政府、生产经营者、消费者和媒体等社会各界人士的全面关注和高度重视。鉴于渔业产品在我国农产品中的重要地位及其丰富的营养价值,为解决渔业产品质量安全管理问题,本研究基于我国特殊的渔业国情,从经济学和管理学角度出发,构建和完善适合我国国情的渔业产品质量安全管理机制。     

辽宁省葠窝水库水质现状与渔业性能评价

近年来,葠窝水库流域综合管理提高了水库水质状况,为了给下一步的渔业生产提供科学依据,在2008-2009年对葠窝水库6个代表性断面进行了4次采样调查和实验室分析,并采用水质综合评价方法对葠窝水库水质进行评价。检测结果表明水质状况总体有所好转,主要污染物为非离子氨和重金属铜,其他指标正常。采用流域综合水质指数法对水库总体...