厚壳贻贝3群体的形态差异与判别分析

运用多变量形态度量学分析方法，对浙江沿海嵊泗、舟山、台州3个地理群体厚壳贻贝的4个形态性状进行了形态差异研究。聚类分析和主成分分析结果表明，嵊泗群体和台州群体首先聚类，之后与舟山群体聚类。主成分分析中，2个主成分的贡献率分别为：主成分1为47．01％，2为25．07％，累积贡献率为72．08％。判别分析结果表明，3群体间形态差异显著（P〈0．01）。建立3群体的判别函数，判别准确率P。N80．00％。86．66％，P2为80．65％。85．71％。3群体的综合判别率为83．33％。     

日本沼虾4种群的形态差异分析

4种群日本沼虾（Macrobrachium nipponensis）分别取白洪泽湖、太湖、广西3地大然水域和浙江德清人工养殖池塘。经在相似条件下暂养7个月后，运用3种多元分析方法对四者的10项形态比例参数进行比较研究。聚类分析结果表明，养殖种群与洪泽湖种群的形态最接近，而与太湖种群、广四种群的趋异程度逐渐增加。主成分分析结果显示，养殖种群的成体规格小于吲期的3个野生种群，而3个野生种群中又以洪泽湖种群的规格最小。以判别分析建立了4种群的判别函数，判别准确率分别为：76．7％-86．7％（P1）和74．3％～96．0％（P2），综合判别率81．7％。3种多冗分析结果均认为，4种群R本淄虾在形态上已产生一定程度的差异，且集中表现在头胸甲部的性状上，但所有差异均未达到业种水平，须有多项参数综合判别才能辨别；养殖种群的小型化与选种不当密切相关。     

3个单齿螺地理群体形态差异分析

运用多变量形态度量学方法,采用8个量度特征对大连、舟山和厦门3个单齿螺（Monodonta labio）地理群体的形态差异进行分析研究.聚类分析和主成分分析结果表明,舟山群体和厦门群体形态最为接近,大连群体趋异程度最大.主成分分析得出了3个主成分,其贡献率主成分1为57.49％,主成分2为18.80％,主成分3为10.40％,累计贡献率为86.69％.通过判别分析,建立了3个地理群体的判别函数,其判别准确率P1为63.16％ ～ 81.82％,准确率P2为60.00％ ～81.82％,综合判别率为74.13％.3个地理群体间最大差异系数为0.191 8～0.945 7,均小于1.28.多元分析结果表明,3个地理群体的形态特征之间有一定程度的差异,但差异尚未达到亚种水平.     

五种蚌的形态变异与判别分析

运用多变量形态度量学方法，采用6个形态性状对褶纹冠蚌、三角帆蚌、圆背角无齿蚌、椭圆背角无齿蚌和球形无齿蚌5种蚌的种间以及地理种群间的形态变异进行了研究。主成分分析构建了2个主成分，第一主成分受4个性状的影响，贡献率为54.17%；第二主成分受1个性状的影响，贡献率为34.08%。主成分分析和聚类分析表明，褶纹冠蚌与三解帆蚌形态相近，随圆背角无齿蚌与球形无齿蚌外形相拟。方差分析和t检验表明，褶纹冠蚌和三解帆蚌的不同地理种群分别表现出形态上变异。建立了5种蚌的判别函数，三角帆蚌和圆背角无齿蚌的判别准确率均为100%，褶纹冠蚌、椭圆背角无齿蚌和球形无齿蚌的判别准确率依次为98.92%、86.36%和96.88%，总判别准确率为97.83%。     

长江主要一级支流中华倒刺鲃形态差异比较

采用传统形态学和框架分析法,运用单因素方差分析、聚类分析、主成分分析和判别分析4种多元分析方法对嘉陵江、赤水河、清江3个中华倒刺鲃(Spinibarbus sinensis)种群288尾样本的30个形态比例性状进行比较研究.结果表明,3个种群的全长/体长、叉长/体长、体宽/体长等29个性状差异显著(P＜0.05);聚类结果显示,嘉陵江种群与赤水河种群首先聚为一类,认为嘉陵江种群与赤水河种群形态最为相似;主成分分析构建了8个主成分,累计贡献率为62.93％;以Bayes逐步判别分析方法选用16个判别效果较好的比例性状建立了3个中华倒刺鲃地理种群的判别函数,综合判别率达到99.31％.研究结果显示,嘉陵江种群与赤水河种群形态较为相似,而两者与清江种群形态差异较大.本研究从形态特征上为长江上游中华倒刺鲃种群的划分提供了科学依据.     

沅江与西江水系大眼华鳊的形态差异

为了探讨沅江和西江水系大眼华鳊（）的形态差异及分化程度，对两个水系5个种群的147个样本进行了测量，共获得9个可量性状和21个框架性状，通过多元分析方法进行了比较。Friedman非参数检验的结果显示，5个种群间的体侧各部分面积存在显著性差异（<0.01）。聚类分析将5个种群分为三支，其中西江两个种群为一支，沅江干流和沅江锦江种群为一支，沅江清水江种群单独为一支。主成分分析共提取出6个主成分，对总方差的累计贡献率为81.93%，贡献率大的性状集中在尾柄部、头部和躯干前部。判别分析筛选出头部和尾柄部的10个性状，分别建立了5个种群的判别函数，判别成功率在92%~100%。3种多元分析方法从框架形态差异上将沅江和西江水系大眼华鳊的种群有效区分开来，为5个种群的形态差异及资源评价提供了基础资料。     

不同地区克氏原螯虾群体的形态差异分析

运用3种多元统计方法,对江苏、安徽、山东和湖北4个不同地区克氏原螯虾(Procambarus clarkii)野生群体的13个形态比例参数进行比较研究.聚类分析结果显示,山东和江苏2个克氏原螫虾群体之间的形态最为接近,而与湖北和安徽群体间趋异程度逐渐增大.主成分分析中,雌性群体贡献率分别是主成分1为46.104％、主成分2为25.375％、主成分3为10.830％,累积贡献率为82.309％；而雄性群体贡献率分别是主成分1为50.611％、主成分2为26.365％、主成分3为8.623％,累积贡献率为85.599％.判别分析中,雌体准确率P1为70.6％～100.0％,P2为52.9％～100.0％,综合判别率为87.6％；雄体准确率P1为66.7％～100.0％,P2为66.7％ ～ 100.0％,综合判别率为92.1％.研究结果表明,不同地区克氏原螯虾群体间已经产生了一定程度的形态差异,且主要表现在头胸甲部和腹部的性状上,但这些差异尚未达到亚种水平,需多项参数综合分析才能进行不同群体间的辨别.     

北方须鳅4个地理种群的形态差异与判别分析

用聚类分析、主成分分析、判别分析等方法比较了图们江、松花江、鸭绿江、黑龙江4个地理种群北方须鳅Barbatula nuda的14个形态性状，探讨了不同地理种群间的形态差异。单因素方差分析显示：4个地理种群北方须鳅的头高/体长差异显著（P〈0.05），头长/体长、尾柄长/体长、背吻距/体长、背尾距/体长差异极显著（P〈0.01）；主成分分析与聚类分析结果基本一致，黑龙江和鸭绿江差异最小，其次是图们江和松花江，而黑龙江与图们江，鸭绿江与松花江种群间差异较大；判别分析获得了6个比例性状，构建了区分上述4个种群的判别函数，综合判别准确率达87％。研究显示，北方须鳅的4个地理种群间形态特征产生了一定的差异，可以运用判别分析将其进行初步区分。     

凡纳滨对虾６群体的形态差异及判别分析

运用3种多元分析方法对6个不同地理群体凡纳滨对虾的形态差异进行了比较研究，聚类分析显示广东和厦门的群体形态较为接近，而与浙江，海南三亚（盐度10‰、70‰）的差异程度较大，渤海湾捕捞的野生凡纳滨对虾与另外5个群体欧氏距离最远；主成分分析构建了4个主成分，贡献率分别为主成分1：28.96%，主成分2：18.22%，主成分3：14.89%，主成分4：10.51%，累计贡献率72.58%；判别分析结果，判别准确率P1为76.7%-96.6%，判别准确率P2为82.3%-100%，综合判别准确率为88.33%。虽然6个凡纳滨对虾群体在形态上已有一定程度的差异，但均未达到亚种水平。     

红鳍东方鲀(Takifugu rubripes)雌、雄个体的形态特征比较

为了比较红鳍东方鲀(Takifugu rubripes)雌、雄个体的形态差异,基于主成分分析、逐步判别分析和T检验的方法,以红鳍东方鲀雌、雄群体的17个比例性状为分析对象进行研究.主成分分析构建了3个反映形态特征信息的综合性指标-主成分1、主成分2和主成分3,贡献率分别为46.776％、27.668％和7.122％,3个主成分累积的贡献率为81.566％,两个群体之间存在明显的偏离;判别分析结果显示,根据各变量对判别函数的贡献大小,筛选出两个比例性状,即体宽/体长、体周长2/体长,利用这两个性状建立起红鳍东方鲍的雌、雄判别模型,对雌、雄共72个个体的判别准确率为81.9％;T检验结果显示,体宽/体长在红鳍东方鲍两性群体间差异极显著(P＜0.01),体周长2/体长在红鳍东方鲍两性群体间差异显著(P＜0.05).综合分析实验结果表明,红鳍东方鲀雄性与雌性相比,体形较宽,体周长2较长.红鳍东方鲀雌、雄的形态差异为繁育和选育过程中的性别鉴定提供了新的方法和理论依据.     

Achieving sustainable aquaculture: Historical and current perspectives and future needs and challenges

Important operational changes that have gradually been assimilated and new approaches that are developing as part of the movement toward sustainable intensive aquaculture production systems are presented via historical, current, and future perspectives. Improved environmental and economic sustainability based on increased efficiency of production continues to be realized. As a result, aquaculture continues to reduce its carbon footprint through reduced greenhouse gas emissions. Reduced use of freshwater and land resources per unit of production, improved feed management practices as well as increased knowledge of nutrient requirements, effective feed ingredients and additives, domestication of species, and new farming practices are now being applied or evaluated. Successful expansion into culture of marine species, both off and on shore, offers the potential of substantial increases in sustainable intensive aquaculture production combined with integrative efforts to increase efficiency will principally contribute to satisfying the increasing global demand for protein and food security needs.     

Fish assemblage associations and thresholds with existing and projected oil and gas development

Energy development threatens fish and wildlife resources worldwide. This study used constrained ordinations to show fish assemblage structure associated with oil and gas well densities in the Colorado River Basin, Wyoming, but well densities explained only 6.4% of assemblage structure when compared to other factors. Threshold Indicator Taxonomic ANalysis showed significant negative threshold responses by some species to small levels of development (<0.15 wells km^?2), whereas positive thresholds were less distinct. Some native and imperilled species could be disproportionately affected if future oil and gas development proceeds in a manner that will impact aquatic resources. Although existing development has not substantially influenced regional fish assemblage structure, it appears to affect a subset of species. Understanding assemblage‐level responses to development can help land managers determine appropriate development levels, prioritise areas for monitoring associated with future development and identify where land protection measures may be needed to offset potential risks.     

Gar biology and culture: status and prospects

Many lepisosteid populations in North America have declined and many are now threatened as a consequence of habitat loss and alteration and commercial and sport overfishing. Over the last two decades, morphological, histological and molecular studies allowed distinguishing between different phases of development and the nutritional condition of larvae. Ontogeny of the digestive enzymes of gar larvae indicated the possibility to feed them artificial feeds since early developmental stages. An in vitro digestibility system to test different feed ingredients has been used. Important characteristics of artificial diets were identified through different feeding experiments. Endocrinological studies showed the feasibility of altering larval development and the digestive capacity of larvae. Cloning of gar growth hormone opened new avenues to enhance growth in the gars. Plasmatic vitellogenin was isolated and purified, to develop a competitive enzyme‐linked immunosorbent assay, which allowed the straightforward separation of males from females to establish appropriate proportions for reproduction and also was used to evaluate hormonal protocols to induce gonad recrudescence and spawning. This review analyzes the biology, ecology and physiology of different gar species as a basis for their domestication, mass production of larvae for repopulation experiments and for the culture of commercial‐size gar.     

添加植酸酶日粮不同磷水平和钙磷比对生长肥育猪血液生化指标和骨骼性能的影响

本试验利用饲养试验方法,研究玉米-豆粕型日粮中添加植酸酶时不同磷水平和钙磷比对生长肥育猪血清指标和骨骼性能的影响。试验选用162头20kg左右的杜长大三元杂交猪进行2×3(磷水平×钙磷比)因子饲养试验,试验分2个阶段进行,前期为生长期体重在20-60kg,后期为肥育期体重为为60-100kg。结果表明:添加植酸酶日粮磷水平对血清磷含量和碱性磷酸酶的活性影响显著(P<0.05);钙磷比对血清钙和血清磷含量的影响显著(P<0.05);添加植酸酶日粮磷水平和钙磷比对生长肥育猪骨骼性能的影响不显著(P>0.05)。在添加植酸酶条件下,降低日粮磷水平不影响猪的正常生长发育。     

温度与盐度对老年低额蚤和蚤状蚤生长及生殖的影响_

温度与盐度对老年低额蚤和蚤状蚤生长及生殖的影响王丹丽，李明云，杨天勇，胡章（宁波大学，３１５０１０）关键词老年低额　，蚤状　，温度，盐度，生长，生殖ＥＦＦＥＣＴＳＯＦＴＥＭＰＥＲＡＴＵＲＥＡＮＤＳＡＬＩＮＩＴＹＯＮＧＲＯＷＴＨＡＮＤＲＥＰＲＯＤＵＣＴ...     

奶牛酮病发病机理研究进展

结合国内外目前研究状况较为详细的综述了奶牛酮病的病因与发病机理,并分析了奶牛酮病发生的生化机制。旨在对临床实践中很好的认识诊断和群体监控奶牛酮病提供较为系统的理论依据,保证奶牛群的高产和稳产,从而创造良好的经济效益。     

Esophagoscopy and gastroscopy in dogs and cats. Technics and indications

A report is presented of esophagoscopy and gastroscopy in cats and dogs using flexible endoscopes. Following consideration of the basic equipment, an account is given of patient preparation and anesthesia, topography, investigation technique and normal findings. Diagnostic potential, indications and risks involved are discussed.     

加快城乡统筹，推进我国农垦体制创新与经济发展的研究与思考

“十一五”以来，我国农垦加快体制机制改革、结构调整和经济增长方式的转变的步伐，参与市场竞争，努力提升企业和产品竞争力，经济社会事业发展较快，对国家的贡献提升，职工收入、生活质量明显提高和改善，示范引领作用不断增强。本文针对农垦体制机制创新进展滞缓，战略定位与发展方向不明，经济增长方式转变和结构调整缺乏资本、人才、技术的支撑，没有处理好改革、发展、稳定、民生的关系，投资匮乏，发展后劲不足，人才短缺和劳动力素质低下的现状，提出在未来农垦体制机制创新中要特别关注改革方向、目标设定与评估，改革要在现行法律法规的框架内运作，改革时机的选择，处理好改革发展稳定与民生的关系，调整好内部利益分配关系，自觉融入区域经济，与地方协同发展等问题。为了促进农垦的发展，建议国家加大对农垦体制机制创新、现代农业建设、国有农场土地资源的保护、社会保障体系的完善等财政和政策的支持力度。     

川渝地区鸡皮刺螨的流行与综合防治

鸡皮刺螨是鸡的一种体外寄生的节肢动物,流行十分广泛,对养殖业发展有严重影响。为了解鸡皮刺螨的发病情况,对川渝两地的126个鸡场进行流行病学调查,感染率高达71%。同时,介绍了鸡皮刺螨的生活史、危害及防治措施,是防制鸡皮刺螨不可多得的资料。     

Composition and diversity of fish and fish catches in closures and open-access fisheries of Kenya

Abstract  Catch composition, relative abundance and diversity of fish catches in open access and three old fisheries closures were compared and contrasted with previous ecological studies. There was less variation in catch community composition among the fishing grounds than the closures, suggesting that fishing has homogenised catch composition. The trap survey found that some parrotfish [ Leptoscarus vaigiensis (Quoy &Gaimard), Calotomus carolinus (Valenciennes) and Scarus ghobban Forsskål] were relatively more common and that some important predators of macro-invertebrates [ Balistapus undulatus (Mungo Park) and Cheilinus chlorourus (Bloch)] were less common in the fishing grounds than closures. Unexpectedly, and in contrast to visual census results, cumulative number of species in catch surveys was higher in open access than closures sites. This may result from fishers covering more area and habitat or a reduction in the catch of competitively subordinate and rare species by aggressive, early-caught fish that can dominate bait. Comparisons of ecological visual census surveys and fisheries-dependent methods indicated that small differences in catch composition can reflect larger ecological differences and that baiting methods can underestimate biodiversity. Ecological impacts of fishing and large-scale changes in marine ecosystems must be considerable given the many fisheries-dependent assessments report modest changes.