温度、盐度和光照对海蜇足囊繁殖的影响

在实验室条件下，就温度、盐度和光照对海蜇（Ｒｈｏｐｉｌｅｍａｅｓｃｕｌｅｎｔａｋｉｓｈｉｎｏｕｙｅ）足囊形成和萌发的影响进行观察。温度实验在０～３０℃范围内设７组，盐度实验在２～３２．１‰范围内设１６个梯度，光照分为自然光和黑暗两组。实验显示：１０℃以上海蜇无足囊繁殖迹象，１５～３０℃范围内，随温度升高，海蜇足囊繁殖能力增强；６‰以下盐度，海蜇不能进行足囊繁殖，２０～２２‰是海蜇足囊繁殖的最适盐度；黑暗有利于足囊繁殖。温度是足囊繁殖的关键因子，盐度和光照是足囊繁殖的充分条件。作者认为，适宜的环境因子是海蜇螅状体形成的必要条件，尽管足囊可以抵御外界的恶劣环境，但足囊形成并非需要不良环境因子诱导，足囊繁殖是海蜇螅状体一种正常的无性繁殖方式     

圆尾斗鱼的繁殖及其对蚊幼虫孳生的控制

圆尾斗鱼的繁殖及其对蚊幼虫孳生的控制熊国根（江西省水产科学研究所南昌３３００３９）圆尾斗鱼（Ｍａｃｒｏｐｏｄｕｓｃｈｉｎｅｎｓｉｓ）是我国分布广泛，可行气呼吸的小型鱼类。以前对它的生活习性已作了基本阐述．［１］［２］鉴于圆尾斗鱼喜食蚊子的幼虫和蛹，近...     

绥芬河三块鱼属（Tribolodon）鱼类的分类学讨论

绥芬河是注入日本海的水系之一 ,其溯河洄游性鱼类种类较多 ,其中被当地渔民俗称“金滩头、银滩头和黑滩头”的鱼类是鲤科唯有的溯河洄游性鱼类。在分类学上一直都存在着争议。任慕连 ( 1 981 )将其归于三块鱼Ｔｒｉｂｏｌｏｄｏｎｂｒａｎｄｔｉ (Ｄｙｂｏｗｓｋｉ)的三个不同的洄游群体 ;尹家胜 ( 1 991 )认为金滩头和黑滩头为滩头雅罗鱼ＬｅｕｃｉｓｃｕｓｂｒａｎｄｔｉＤｙｂｏｗｓｋｉ的两个不同的洄游群体 ,而银滩头为黑滩头的性不成熟群体 ;董崇智 ( 1 995,1 996 )和张觉民 ( 1 995)认为存在两个种即珠星雅罗鱼Ｌｅｕｃｉｓｃｕｓｈ…     

不同投饵方式对黑鲪生长的影响

鱼类的生长受众多因素的影响,如温度、盐度、光周期、食物以及鱼类自身的生理状态等［１］。单就食物而言,生长就不仅受食物性质、食物数量的影响,而且还受投饵方式的影响［２,３］。在自然状态下,鱼类摄食有一定的周期性;在养殖中,投饵也常采用一定的时间间隔［４,５］,但研究不同投饵方式对鱼类生长的影响还较少。黑鲪（Ｓｅｂａｓｔｏｄｅｓｆｕｓｃｅｓｃｅｎｓ）是重要的海水养殖鱼种之一,目前关于黑鲪的研究还比较少［６］。本研究考察了不同投饵方式对黑鲪生长的影响,以期为其养殖提供基础数据。收稿日期：１９９８－１２…     

球等鞭金藻培养液中卵形小球藻的繁殖控制方法

不同藻类生长、繁殖的生态条件是不尽相同的利用球等鞭金藻（Ｉｓｏｃｈｙｓｉｓｇａｌｂａｎａ）与其污染藻－卵形小球藻（Ｃ．ｏｖａｌｉｓ）生态习性的差异，在培养过程中对藻液ＰＨ值进行人工控制，使其保持在球等鞭金藻生长的适宜范围之内，从而达到促进球等鞭金藻生长，控制卵形小球藻繁殖之目的。本文通过对３组污染程序不同的藻液的对比培养实验发现，在温度范围１７－１８．４℃，照度范围３０００－８０００Ｌｕｘ条件下，     

一种新型混合喷涂原理解析

本文分析了进口发泡机不同于传统的混合两种液料的原理，其关键在于喷嘴中对一种液料在喷嘴孔内高速旋转所造成的密闭式混合。在５．２ＭＰａ情况下计算出在冲射细孔中流速为４３ｍ／ｓ。环流强度８２４９ｃ／ｓ，喷孔流速２５ｍ／ｓ，黑、白料混合时间０．６ｍｓ。密闭式混合比传统方式更优越，改善了环境污染，节省原料消耗。     

北方地区鲶鱼、彭泽鲫鳃霉病的诊断与防治

鳃霉病（Ｂｒａｎｃｈｉｏｍｙｃｏｓｉｓ）又称黑鳃病，近两年来辽宁省的沈阳、辽阳、营口等集约化养鱼区的鲶鱼、彭泽鲫广泛流行，发病率在 ８０％以上。２００１年６月初仅辽阳沈旦镇就有３０个鲶鱼养殖户带鱼前来诊治，彭泽鲫鱼鳃霉病更为普遍，给渔业生产造成重大经济损失。下面将对此病做简要介绍。 ［病原体］鳃霉（Ｂｒａｎｃｈｉｏｍｙｃｅｓ　ＳＰＰ．），据Ｇｒｉｍａｌｄｉ认为属水霉目（Ｓａｐｒｏｌｅｇｎｉａｌｅｓ）真菌。 ［镜下诊断］镜下观察，它的菌丝常弯曲成网状，较细而壁厚，分枝特别多，分枝菌丝由鳃耙、沿着鳃丝…     

人工繁殖蟹苗淡化方法的初步研究

人工繁殖蟹苗淡化方法的初步研究陆开宏，徐如卫，江锦坡（浙江水产学院养殖系，宁波３１５０１０）河蟹（Ｅｒｉｏｃｈｅｉｒｓｉｎｅｎｓｉｓ）系海水繁殖、淡水生长的洄游性甲壳动物，人工繁殖的蟹苗（大眼幼体）由于自身调节渗透压的需要，一般均需淡化后才移入淡水放...     

黑鲷网箱养殖技术

黑鲷（ｓｐａｒｕｓ ｍａｃｐｒｏｃｅｐｈａｈｔｓ），俗称黑加吉、海鲋、黑立等，喜栖于沙泥底质或多岩礁底的浅海水域，一般不作远距离洄游，以小鱼、虾、贝等为食。在我国沿海均有分布，肉质鲜美，属名贵经济鱼类。由于其适应性较强，是网箱养殖的主要品种之一。１海区选择 以水质清洁，风浪较小，透明度较高，无污染的内湾为宜。水质理化条件应较稳定，具体要求应参照“渔业水域水质标准”。 海水流速过慢，影响箱内水体交换，使网箱内溶解氧不足。海水流速过快，虽然水体得到充分交换，但鱼体消耗能量大，影响其生长。一般流速以 １５…     

蓝鳃太阳鱼繁殖与苗种培育试验

蓝鳃太阳鱼 (Ｌｅｐｏｍｉｓｍａｃｒｏｃｈｉｒｕｓ)原产北美。美国将它与绿色太阳鱼 (Ｌｅｐｏｍｉｓｃｙａｎｅｌｌｕｓ)杂交 ,获得杂交一代 ,具有明显的杂交优势 ,个体较大 ,肉质细 ,味道极为鲜美 ,没有肌间刺 ,是美国养殖鱼类之一 ,既是食用鱼 ,又是观赏鱼 ,具有较高的经济价值。1987年我国曾引进蓝鳃太阳鱼 ,但由于其体形偏小 ,生长速度较慢 ,在当时没有引起人们的重视 ,没有形成较大的生产规模 ,对其繁殖与苗种培育的报道不多。湖南省水产研究所报道其性成熟年龄为一冬龄 ,多次产卵类型 ,并营巢繁殖 ;罗继论报道蓝鳃太阳鱼在美国的繁…     

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.     

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.     

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.     

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.     

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。     

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。     

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.     

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...