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根据2012—2013年龙江入海口水域的水质调查数据,对该水域氮、磷营养盐分布状况、结构特征及富营养评价进行了研究。结果表明,2012年和2013年DIN含量范围分别为0.808~5.285、0.610~5.383 mg/L,PO4-P含量范围分别为0.028~0.324、0.096~0.643mg/L,呈不同程度的超标状态并有上升趋势。受海水稀释作用,营养盐浓度由河口向外逐渐降低;受枯水期地表径流减少导致营养盐浓缩的影响,营养盐含量呈现冬、春季高,夏、秋季低的季节性变化;NH4-N在DIN中的占比在51.15%~63.25%和43.88%~69.39%之间,DIN的污染程度主要受NH4-N控制。营养盐结构上N/P比值范围为10.83~13.12,接近适合浮游植物生长繁殖的Redfield比值(16∶1),潜在性富营养化程度评价分析表明该水域处于富营养化状态,N、P营养盐绝对浓度高,可能有赤潮等严重海洋生态问题发生的潜在风险。  相似文献   

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Paddlefish, "Polydon spathula," overwintered in monoculture and in polyculture with fingerling channel catfish, "Ictalurus punctatus," or with rainbow trout, "Oncorhynchus mykiss," were examined for growth and compatibility in nine 0.04-ha ponds. Paddlefish in polyculture had significantly greater (P ≤ 0.05) individual weight gains than those in monoculture. Feed in polyculture treatments probably served as a fertilizer, promoting zooplankton production for paddlefish consumption and growth. Paddlefish in polyculture with fingerling channel catfish had significantly greater (P < 0.05) individual weight gains than paddlefish polycultured with rainbow trout, although there was less feed input with channel catfish than with rainbow trout. Bloody and frayed fins on paddlefish stocked with rainbow trout suggested fin nipping by rainbow trout which may have interfered with paddlefish feeding and growth. Paddlefish overwintered in polyculture with fingerling channel catfish demonstrated increased weight gains and good species compatibility.  相似文献   

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黄海北部春季和夏季浮游动物生态特性与时空分布   总被引:2,自引:0,他引:2  
根据2015年3月(春季)和6月(夏季)对黄海北部辽宁近岸海域的浮游动物调查结果,分析了两个季节的浮游动物种类、生物量、丰度等群落结构特征。此次调查共鉴定出浮游动物47种,其中春季42种,夏季34种。浮游动物以浮游幼虫和小型桡足类为主。桡足类幼虫、棘皮动物幼体、桡足类幼体、洪氏纺锤水蚤、短角长腹剑水蚤、小拟哲水蚤、拟长腹剑水蚤和腹针胸刺水蚤为春季优势种;夏季浮游动物优势种依次为桡足类幼体、洪氏纺锤水蚤,拟长腹剑水蚤、短角长腹剑水蚤、桡足类幼虫、小拟哲水蚤和腹针胸刺水蚤。春季浮游动物平均生物量为512.09mg/m~3,平均丰度为15 522.18个/m~3;夏季浮游动物平均生物量为218.84mg/m~3,平均丰度为7582.39个/m~3;浮游动物生物量和丰度均为春季较高。黄海北部辽宁沿岸海域的浮游动物生物量、丰度较高。水温是影响浮游动物群落结构的重要环境因子。  相似文献   

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冷水性鲑科鱼类肉质鲜美,高蛋白、高不饱和脂肪酸、营养丰富、无肌间刺、易加工,是世界性养殖鱼类,其中大西洋鲑、虹鳟和红点鲑属鱼类等主要养殖鲑科鱼类,一直是水产遗传育种领域的重要研究对象。本文简要叙述了鲑科鱼类遗传育种研究的历史和现状,主要介绍了经济性状遗传参数估计、选择育种、分子遗传与标记辅助育种等方面的研究进展,提出了我国鲑科鱼类遗传育种工作重点研究的方向。  相似文献   

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A review is presented on the species spectrum, biology and epidemiology of endo- and ectoparasites of sheep and goats in Germany. Current therapeutic, prophylactic and metaphylactic measures are given and discussed.  相似文献   

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随着中国改革开放的深入,海洋渔业捕捞的发展正走上正规化,从而使得沿海地区水上安全通信在保障海上生产安全、促进海洋渔业经济稳定发展中的作用越来越重要,特别是近两年来,由政府资助为渔民统一购置安装单边带电台,使渔业无线电通信真正成为"信息交流的桥梁"、"安全生产的耳目"、"科技服务的窗口",是海洋渔业不可替代的通信方式.但随之而来的的问题和矛盾也逐渐显露并严重制约着渔业无线电通信管理事业的健康发展.作为渔业通信管理工作者,如何加强渔业通信网络建设,不断提高为渔民生产服务的质量,确保渔民生命财产安全,成为当前义不容辞的责任.下面结合当前渔业通信管理工作的现状,谈一谈渔业通信管理工作中存在的问题及解决措施.  相似文献   

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淇河鲫与野生鲫形态及染色体差异研究   总被引:2,自引:0,他引:2  
对淇河鲫和普通野生鲫的传统形态学性状和框架性状进行了统计学比较研究,并对其染色体数量进行了检测.试验结果表明,(1)淇河鲫为三倍体,3n=156±,野生鲫为二倍体,2n=100±.(2)淇河鲫在体高、体厚等方面显著大于野生鲫,符合"双倍鲫"的形态特征,且侧线鳞数也多于野生鲫;而野生鲫在头长、尾高方面占优.(3)淇河鲫相对怀卵量显著高于野生鲫,而相对肠长显著低于野生鲫,这与淇河鲫长期处于人工饲养条件有关.  相似文献   

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Abstract Inland fisheries in England and Wales have high economic and social values. Managing participation to maximise fishery performance is key to maintaining this status. The capital value of fishing rights for migratory salmonid fisheries is €165 million. Coarse fisheries contribute €1030 million to the economy. The central tenet to increasing participation in recreational salmonid fisheries is that an increase in stock size will result in more anglers accessing the fishery. This was examined for salmon on the rivers Usk and Lune where exploitation restrictions increased the number of salmon available to anglers. On the River Lune, the number of salmon available post‐intervention increased by 66%. There was no significant increase in catch while the number of anglers decreased by 16.3%. On the River Usk, the closure of the net fishery potentially resulted in an additional ~1200 salmon being available. Following closure, there was no significant change in rod catch or in the number of anglers. Increased participation is dependent less upon stock manipulation for coarse fisheries and more upon facilitating the activity. In recent years, urban fishery development programmes have provided improved access to local fishing opportunity. Also, new anglers have been targeted through campaigns such as Get Hooked on Fishing and the Scout Angler Badge.  相似文献   

10.
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.  相似文献   

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