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1.
Nathanael Hishamunda Neil B. Ridler 《Aquaculture Economics & Management (Blackwell Science)》2013,17(3-4):167-178
Abstract Commercial aquaculture which, for this paper, is defined as the rearing of aquatic organisms that is profit oriented and primarily by the private sector, contributes to food security, directly by producing food fish, and indirectly by generating employment, and thus, income for the purchase of food. In addition, commercial aquaculture can be sustainable because it depends on private, rather than public funds that are usually lacking or scarce. The paper describes some enabling policies that are conducive to the promotion of commercial aquaculture. In particular it focuses on administrative and legal frameworks. The paper concludes that development of aquaculture can be enhanced by legislation specific to the sector rather than relying on general fisheries legislation; such a legislative framework (particularly for land‐based aquaculture) would resemble that of agriculture. Regulations require expensive and time‐consuming monitoring and enforcement; they should focus on environmental protection and a sustainable industry. 相似文献
2.
研究洞庭湖水文泥沙参数间的相关性,分析泥沙的冲於演变规律,为正确评价洞庭湖的淤积特性和江湖淤积的有效治理提供理论支撑。基于湘潭站等9座重要水文站2002-2016年间的水文泥沙监测资料,系统梳理洞庭湖水系的水沙特性及水文泥沙参数间的相关性。研究表明:松滋西河、澧水和洞庭湖2016年的年径流量相比2002年增大0.3%～16.2%,其他河道降低2.9%～34.2%;资水的泥沙中值粒径2002-2016年降低57.1%,其他河道增大26.7%～300%;资水和洞庭湖2016年的年均含沙量、年输沙量相比2002年分别增大21.5%～22.2%、5.7%～40.6%,其他河道分别降低13.6%～82.9%、6.7%～88.8%;参数间相关性由强到弱排序为年均含沙量-年输沙量、年径流量-年输沙量、年径流量-年均含沙量、年均含沙量-中值粒径、年输沙量-中值粒径、年径流量-中值粒径;东、南洞庭湖入湖泥沙量和淤积量在时序上分别下降29.9%、144.73%,出湖泥沙量、排沙比分别增大55.72%、113.7%;西洞庭湖入湖泥沙量、出湖泥沙量、淤积量、排沙比在时序上降低24.06%～88.24%。三峡水库蓄水拦沙的作用降低了洞庭湖的入湖沙量、淤积量,增大了排沙量和排沙比,有利于洞庭湖寿命的延长。 相似文献
3.
Use of macrobenthic infaunal communities in the monitoring and control of the impact of marine cage fish farming 总被引：1，自引：0，他引：1
Benthic macrofaunal community changes are used extensively to monitor the impact of polluting discharges to the marine environment. Regulatory and pollution control authorities have recognized the particular value of the well studied and reported responses of infaunal communities to organic pollution including wastes from aquaculture. Benthic systems are embraced in both the consent (licence) to discharge and monitoring procedures for marine cage fish farms in the Clyde River Purification Board's (CRPB) area. The relevant protocols of the CRPB are described and data are presented from impact studies throughout west central Scotland, focussing on the sedimentary environment (macrobenthos, organic carbon and redox: Eh). Macrobenthic infaunal responses, though not fully understood, were considered to provide the best measure to date of determining the impacts of organic wastes from cage fish farming and a possible way forward in developing benthic Environmental Quality Standards (EQSs) for aquaculture. Some patterns in physico-chemical data were identified, but frequently, the relationship both with benthic infaunal data and each other were inconsistent. Grossly impacted faunal communities varied little between sites and could readily be described by the simple community determinands of abundance (A), species richness (S) and Shannon Weiner diversity index (H). Moderate to lightly impacted zones were less easily defined but detailed faunal studies have allowed the selection of some widely distributed marker species. However, site-specific observations emphasized the site individuality and difficulties of setting EQSs across the industry. Using the principles of enhanced species populations and by identifying marker species, measurable impacts were found to extend further than previously reported. In naturally enriched systems, like the Firth of Clyde and some sea lochs, difficulty in separating slight effects from background was experienced. Continued monitoring and impact assessment, as well as building a better biological data base, may help develop appropriate benthic EQSs relating to aquaculture. 相似文献
4.
A. D. Jamieson 《Aquaculture Research》1979,10(2):63-72
The sport-fishery for the Atlantic salmon Salmo salar L. has been developed in Scotland for a considerable period of time yet for various reasons there are very few details published on those aspects of the sport which are of interest to a student of any natural or recreational resource. There is a need for information on such aspects as the ownership and boundaries of the fisheries, their qualities, their capacities and their availability. This information can best be presented in map form and this paper illustrates those parameters with information which was available for the salmon fisheries of the River Conon and the River Blackwater in Ross-shire, which are owned by the North of Scotland Hydro-Electric Board. This sort of information would be an essential task of any reorganized salmon fisheries administration, such as the Area Boards originally proposed by the Hunter Report of 1965. 相似文献
5.
中华鳖七群体体形和腹部黑斑图案的差异比较 总被引：3，自引：2，他引：3
对我国中华鳖代表性7个地方群体的成鳖阶段和后备亲鳖阶段的体形和腹部黑斑图案进行了，比较和分析。(1)把包括背甲周长、背甲宽、裙边后侧宽等16个参数转化为以背甲长为基数的15项比例性状进行多元函数分析。聚类分析表明，太湖鳖和崇明鳖较近，黄河鳖和淮河鳖较近，洞庭湖鳖和鄱阳湖鳖较近。主成份分析表明，把7群体一起分析的绘图，相互覆盖较多，不易分清：若是取3个群体，如对黄河鳖、洞庭湖鳖及太湖鳖分析绘图，则趋同性和趋异性十分清楚。判别分析表明，7群体的判别准确率在44％～73％之间，黄河鳖群体的判别准确率最高；(2)裙边宽厚度是中华鳖的重要经济指标。黄河鳖、淮河鳖及洞庭湖鳖的裙边均较宽而厚，其裙边后侧宽／背甲长之比超过7群体总平均值1～4．6个百分点；(3)中华鳖体色存在群体间固有的差异。首先表现在腹部的黑色斑块的有无和多少上，在后备亲鳖阶段，黄河鳖腹部全白的比例达100％，洞庭湖鳖和鄱阳湖鳖及淮河鳖腹部全白的比例在80％～90％；太湖鳖、崇明鳖及台湾鳖腹部全白的比例仅12％～22％。其次表现在腹部黑色斑块的出现频率和黑色程度有从黄、淮河流域和长江中游水域向长江下游水域及台湾增高、增强的明显趋势。黄河鳖、淮河鳖、洞庭湖鳖及鄱阳湖鳖是为“玉鳖”群，太湖鳖、崇明鳖及台湾鳖是为“花鳖”群。中华鳖腹部黑色斑块图案，是既受遗传控制，也受环境影响，还受遗传-环境相互作用的复杂表型。 相似文献
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(Hemiculter leucisculus)和鱇白鱼(Anabarilius grahami)分别是抚仙湖的外来鱼类和土著鱼类。研究了不同营养状态(低、中、高)水体中二者肝脏酶活性的变化;其中,低营养状态水体组是中、高营养水体组的对照。养殖40d后,随着水体营养状态的提高,和鱇白鱼肝脏中的谷草转氨酶(AST)、谷丙转氨酶(ALT)和乳酸脱氢酶(LDH)活性均逐渐降低;中、高营养水体中歺鱼又的超氧化物岐化酶(SOD)活性显著低于对照组,而3个处理组鱇白鱼的超氧化物岐化酶活性没有显著差异。由此推测,富营养化有可能减弱歺鱼又和鱇白鱼肝脏的正常功能,而歺鱼又在高营养水体中可能更容易受到氧化胁迫的威胁。 相似文献
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Abstract. Overexploitation and pollution has led to the decline of Scotland's traditional smelt fisheries. The one remaining commercial fishery is on the River Cree in south-west Scotland and the characteristics of the spawning runs of the smelt, Osmerus eperlanus (L.), on which this fishery is based have been studied with a view to conservation and re-establishment of the species elsewhere in Scotland. The spawning-runs which started in early March when water temperatures were greater than 5°C were characterized by marked temporal changes in size, age and sex ratio. The fish enter the spawning stock at 1+ years of age and, in common with other estuarine smelt populations, are highly fecund. The spawning stock was composed mainly of two age-classes (1+ and 2+ years) and fish of the 1978 year-class dominated the spawning stock in 1980 and 1981. Spawning, which was interrupted during periods of high flow, lasted about 1 week. Male fish tended to remain on the spawning grounds after females had vacated the area. Recommendations for management and re-establishing smelt stocks are discussed. 相似文献
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Abstract. A fungal infection of Atlantic salmon parr (0 +) occurring at low water temperatures, principally in January, is reported from fish farm hatcheries in western Scotland. Clinical signs and histopathology of the disease are described, illustrated, discussed and compared with those of certain other fungal diseases of salmonids. The fungus, provisionally placed in the hyphomycete genus Phialophora is described and illustrated from pure culture, with a discussion of its taxonomic position. 相似文献
9.
长江下游浅水湖泊石臼湖鱼类资源现状及变化趋势 总被引：1，自引：0，他引：1
根据2012-2013年对石臼湖水质和鱼类资源开展的2次调查数据,研究石臼湖水质、鱼类资源现状及演变趋势。采用水质单因子评价方法、营养状态质量指数,结合经济合作与发展OECO富营养湖泊判断标准,研究石臼湖、姑溪河、塘沟河、清水河的水质和富营养化状况;通过商业捕捞的渔获物调查,收集石臼湖和姑溪河鱼类资源数据,分析河网区鱼类种类组成、渔获物结构等渔业资源现状。结果表明,石臼湖及毗邻水域存在一定程度的水污染,且湖区受水量变化影响低于河流区,总体水质状况符合地表水环境质量Ⅲ~Ⅳ类,为富营养状态。石臼湖分布鱼类110种,2012-2013年共调查到54种;其中,石臼湖38种,固城湖33种,姑溪河51种。石臼湖、固城湖和姑溪河主要经济鱼类(数量和重量均超过1%的种类)分别有13、11和9种。石臼湖鱼类主要以鲤[Cyprinus(Cyprinus)carpio]、鲫(Carassius auratus)、鲇(Silurus asotus)等适应静、缓流生境的鱼类为主,并以歺又鱼(Hemiculter leucisculus)、鲫、棒花鱼(Abbotina rivularis)等小型鱼类或小规格个体鱼类(1 000 g)为主;湖区天然渔业资源呈衰退趋势,由于和长江下游干流相通,姑溪河鱼类种类数高于湖区,但其生物量远低于湖区;渔业资源的分布状况与水质状况无明显相关性,与河湖的连通性有关;受枯水期水量偏少、上游和周边来水污染以及高密度水产养殖的影响,石臼湖水质出现氮、磷和有机污染物超标等问题。宜采取源头控污、限制养殖、渔民转产以及人工增殖等措施,保护石臼湖水质,恢复天然渔业资源。 相似文献
10.
暗纹东方鲀生殖洄游期性腺发育特点及人工繁殖的研究 总被引：3，自引：1，他引：2
１９９６～１９９８年,作者从长江下游扬中段采捕暗纹东方鱼屯亲鱼,经暂养促熟处理（微流水刺激、投喂鲜活饵料、不定期注射适量的ＬＨＲＨ－Ａ２）,雌鱼的性腺可发育到Ⅳ期末,对外源激素能引起正常的排卵反应。同时观察了Ⅲ、Ⅳ、Ⅴ期性腺发育的特点。催产药物为ＬＨＲＨ－Ａ２和ＰＧ,三针注射,雌鱼剂量为３５ｍｇＰＧ＋６０μｇＬＨＲＨ－Ａ２／ｋｇ,雄鱼剂量减半。在水温１８～２２℃的条件下,效应时间为１０～３６小时;在２１～２２℃时,胚胎发育时间为１３９～２１０小时。１９９７～１９９８年的平均受精率为８３４％,平均孵化率为７８０％。 相似文献
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中华鳖五群体遗传变异的RAPD分析 总被引：20，自引：1，他引：20
从97个10碱基随机引物中筛选出30个多态性引物,对黄河鳖、淮河鳖、洞庭湖鳖、鄱阳湖鳖及太湖鳖5个群体共100只个体进行RAPD分析.结果表明,中华鳖的遗传多样性较丰富.表现在(1)在获得的341条RAPD扩增带中,有234条(68.6%)呈现多态性;2个引物有可明显地反映种群差异的扩增带,其中S105扩增的1408bp在黄河鳖的出现频率仅为20%,而在另外4个群体的出现频率达80%～90%;S37扩增的438bp在5个群体的出现频率大小为黄河鳖85% >淮河鳖65% >洞庭湖鳖55% >鄱阳湖鳖40% >太湖鳖20%,呈现出从黄河到淮河到长江、从长江的中游到下游逐步降低的遗传渐变现象;(2)多态位点比例(P)的大小顺序为太湖鳖59.25%>洞庭湖鳖56.52%>鄱阳湖鳖55.80%>淮河鳖55.03%>黄河鳖54.43%,但5个群体间的差异不显著(F=0.644<F0.05;4,145=2.45);5群体内的遗传多态度(π)在0.3644～0.3883间;(3)群体内遗传相似度大小顺序为淮河鳖0.782>黄河鳖0.771>鄱阳湖鳖0.768>洞庭湖鳖0.750>太湖鳖0.722,其中太湖鳖与黄河鳖、淮河鳖、鄱阳湖鳖3个群体间的差异显著(P <0.05);(4)分子方差分析(AMOVA)表明,黄河鳖与淮河鳖、洞庭湖鳖及鄱阳湖鳖3个群体间,太湖鳖与黄河鳖、淮河鳖2个群体间有极显著的遗传分化(P<0.001);(5)根据遗传距离,用UPGMA 和NJ法进行聚类分析表明黄河鳖与淮河鳖、洞庭湖鳖与鄱阳湖鳖分别先聚在一起,最后再与太湖鳖聚类,显示太湖鳖在基因组上与其它4个群体鳖存在明显歧化. 相似文献
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Akira P Takagi Satoshi Ishikawa Thuok Nao Sitha Hort Masanori Nakatani Mutsumi Nishida Hisashi Kurokura 《Fisheries Science》2006,72(4):750-754
ABSTRACT: Although the bronze featherback Notopterus notopterus is an important fish in South-East Asia, the population structure has not been investigated. In this study, genetic diversity and population structure of the bronze featherback were examined using nucleotide sequence analysis of the mitochondrial DNA control region for 332 fish collected from Tonle Sap Lake and the Mekong River in Cambodia. The average nucleotide diversity (π) of all samples was 0.033, and the Mekong River samples had higher nucleotide diversity (0.034) than Tonle Sap Lake samples (0.028). The nucleotide diversity between the lake and river samples varied from 0.029 to 0.037. The genetic differentiation between the river and lake populations was also supported by the pairwise F -statistic values and hierarchical analysis of molecular variance, indicating that the Tonle Sap Lake population is genetically isolated from the population in main stream of the Mekong River. 相似文献
13.
<正> 对虾养殖业的迅猛发展,刺激与推动了对虾苗种的生产,沿海各地为数众多的对虾育苗场相继建立,成为苗种供应的基地.在"养虾热"中,上海沿海地区的对虾养殖生产同样得到了长足的发展.养殖面积日益扩大,成为创汇农业的"拳头"产品之一.为满足2万余亩虾池苗种放养的需要,每年向江苏、浙江等省采运数亿尾虾苗,耗费大量的人力、物力、财力.并且对虾苗种生产的丰歉,以及质量的优劣,直接影响对虾养殖的稳产高产和经济效益.地处河口地区的上海沿海海水盐度低,且季节变化幅度大,给对虾育苗技术提出了新的研究课题.上海水产大学、上 相似文献
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目前，国内采用饲养日本鳗鲡的传统方法来饲养欧洲鳗鲡，内中存在两个问题：一是鳗病，其中狂游病发病急，死亡率极高，而红头病虽然发病稍缓，但极难治疗，死亡也较严重；二是各阶段的生长速度明显低于日本鳗鲡。本文对这两大问题进行探讨。 相似文献
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Abstract – Life history strategies and migratory patterns of 71 adult radio-tagged bull trout, Salvelinus confluentus , were studied in the Secesh River watershed within the South Fork Salmon River (SFSR) sub-basin in west-central Idaho, USA during 2003 and 2004. In both years, upstream migrations occurred during late June and early July, migrations into two spawning tributaries during late July and early August, spawning from mid-August through mid-September, and rapid downstream (postspawning) migrations from late August to mid-September. Primary over-wintering areas were Loon Lake, the lower Secesh River (downstream of Loon Creek), and the lower SFSR (downstream of the confluence with the Secesh River). Loon Lake evidently provides sufficient production to allow the adfluvial life history strategy to persist and predominate in the Secesh River, while the fluvial life history strategy was previously found to predominate in the nearby East Fork SFSR. Adfluvial, nonconsecutive-year migrations were the predominant life history strategy. Only seven fish made consecutive-year migrations to Lake Creek; however, only one of these fish, a female, utilised a spawning tributary in both years and showed spawning tributary fidelity. Three consecutive-year migrants and three in-season migrants showed over-wintering site fidelity by returning to Loon Lake in September, 2004. The life history variations observed for bull trout in the Secesh River watershed are similar to those observed for bull trout throughout their range and to those of other charr species worldwide, yet the development of distinct migration patterns demonstrate the adaptability of the species to a range of available habitats. 相似文献
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Abstract. Two studies were conducted to determine the effects of rearing Snake River cutthroat trout, Oncorhynchus clarki Richardson, and Eagle Lake rainbow trout, Oncorhynchus mykiss Richardson, in oxygen supersaturated water. The performance of cutthroat trout held at oxygen saturation as high as 172% was compared with that of control fish held in water at or below saturation. At an oxygen saturation level of 172%, total gas pressure reached 117% in late afternoon, and nitrogen saturation was reduced to 93%. The rainbow trout were held at a maximum of 150% oxygen saturation; total gas pressure did not exceed 112% in late afternoon and nitrogen saturation was reduced to 99%. Fish growth, fin quality and feed conversions were not significantly affected in either species. At the termination of the study gas bubble disease was observed in 94% of the cutthroat trout held in oxygen supersaturated water. Gas bubble disease was not observed in rainbow trout. 相似文献
19.
Spawning site fidelity and apparent annual survival of walleye (Sander vitreus) differ between a Lake Huron and Lake Erie tributary 
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下载免费PDF全文 Todd A. Hayden Thomas R. Binder Christopher M. Holbrook Christopher S. Vandergoot David G. Fielder Steven J. Cooke John M. Dettmers Charles C. Krueger 《Ecology of Freshwater Fish》2018,27(1):339-349
Fidelity to spawning habitats can maximise reproductive success of fish by synchronising movements to sites of previous recruitment. To determine the role of reproductive fidelity in structuring walleye Sander vitreus populations in the Laurentian Great Lakes, we used acoustic telemetry combined with Cormack–Jolly–Seber capture–recapture models to estimate spawning site fidelity and apparent annual survival for the Tittabawassee River in Lake Huron and Maumee River in Lake Erie. Walleye in spawning condition were tagged from the Tittabawassee River in Lake Huron and Maumee River in Lake Erie in 2011–2012. Site fidelity and apparent annual survival were estimated from return of individuals to the stream where tagged. Site fidelity estimates were higher in the Tittabawassee River (95%) than the Maumee River (70%) and were not related to sex or fish length at tagging. Apparent annual survival of walleye tagged in the Tittabawassee did not differ among spawning seasons but was higher for female than male walleye and decreased linearly as fish length increased. Apparent annual survival of walleye tagged in the Maumee River did not differ among spawning seasons but was higher for female walleye than male walleye and increased linearly as fish length increased. Greater fidelity of walleye tagged in the Tittabawassee River than walleye tagged in the Maumee River may be related to the close proximity to the Maumee River of other spawning aggregations and multiple spawning sites in Lake Erie. As spawning site fidelity increases, management actions to conserve population structure require an increasing focus on individual stocks. 相似文献