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1.
张俊 《淡水渔业》2001,31(5):56-58
据“八五”、“九五”科技资料统计 :近 2 0年来 ,我国水产品的年均增长率达到 10 5 % ,超过世界年均增长率 6 8%的发展速度。 1998年渔业总产值在农业总产值中的比例已超过 10 % ,而水产品总产量达到 390 6万吨 ,占世界水产品增加总量的 5 2 8% ,从1989年起我国水产品产量已连续 9年位居世界首位 ,人均水产品 31公斤 ,超过世界人均水平 10公斤以上 ,我国渔业的科技进步贡献率目前已达到 4 8%左右 ,我国的农业科技 ,特别是渔业科技一直是在负重前行 ,但它的迅猛崛起已成为农业中发展最快的产业之一 ,并在世界渔业大格局中占有重要的地位。…  相似文献   

2.
Drag force acting on biofouled net panels   总被引:1,自引:0,他引:1  
Measurements were made to assess the increase in drag on aquaculture cage netting due to biofouling. Drag force was obtained by towing net panels, perpendicular to the incident flow, in experiments conducted in a tow tank and in the field. The net panels were fabricated from netting stretched within a 1 m2 pipe frame. They were towed at various speeds, and drag force was measured using a bridle-pulley arrangement terminating in a load cell. The frame without netting was also drag tested so that net-only results could be obtained by subtracting out the frame contribution. Measurements of drag force and velocity were processed to yield drag coefficients.

Clean nets were drag tested in the University of New Hampshire (UNH) 36.5 m long tow tank. Nets were then exposed to biofouling during the summer of 2004 at the UNH open ocean aquaculture demonstration site 1.6 km south of the Isles of Shoals, New Hampshire, U.S.A. Nine net panels were recovered on 6 October 2004 and immediately drag tested at sea to minimize disturbing the fouling communities. The majority of the growth was skeleton shrimp (Caprella sp.) with some colonial hydroids (Tubularia sp.), blue mussels (Mytilus edulus) and rock borer clams (Hiatella actica). Since the deployment depth was 15 m (commensurate with submerged cages at the site), no algae were present. The net panels had been subject to several different antifouling treatments, so the extent of growth varied amongst the panels. Drag force measurements were made using a bridle-pulley-load cell configuration similar to that employed in the tow tank. Fixtures and instruments were mounted on an unpowered catamaran that was towed alongside a workboat. Thus, the catamaran served as the “carriage” for field measurements.

Increases in net-only drag coefficient varied from 6 to 240% of the clean net values. The maximum biofouled net drag coefficient was 0.599 based on net outline area. Biofouled drag coefficients generally increased with solidity (projected area of blockage divided by outline area) and volume of growth. There was, however, considerable scatter attributed in part to different mixes of species present.  相似文献   


3.
采用静水试验法,在水温29.1~30.7℃,pH 8.0~8.2,盐度29.5的条件下,用敌百虫、甲氰菊酯和益扫剂3种药物对体长2~3 cm裸体方格星虫( Sipunculus nudus )稚虫进行了急性毒性试验,以期为星虫养殖生产中虫害防治合理用药提供参考.结果表明,3种药物对星虫稚虫的24和48 h LC 50以及安全浓度分别为敌百虫1.03,0.67和0.09 mg·L -1;甲氰菊酯0.70,0.54和0.10 mg·L -1;益扫剂0.72,0.48和0.06 mg·L -1.  相似文献   

4.
卤虫携带白斑综合征病毒的研究   总被引:3,自引:0,他引:3  
邓灯 《水产学报》2005,29(4):524-528
卤虫是是,蟹苗种培育的关键动物性饵料,查清其能否携带白斑综合征病毒,对培育健康苗种至关重要。2002年7月至10月,自盐田中取野生卤虫,经暂养后选20尾抱卵雌虫,每尾置1个烧杯中,投喂单胞藻,产卵后取出亲体;20d后,每个烧杯中取5尾子一代个体,利用巢式体外DNA扩增技术对亲体和子一代成体进行WSSV病毒检测,检测结果显示:卤虫中可扩增出特异性的,与引物设计吻合的DNA片段;DNA测序分析表明,扩增片段的DNA序列与白斑综合征病毒序列一致;野生卤虫携带白斑综合征病毒的阳性率为58%,实验条件下野生卤虫后代的阳性率为43%,同一家系中,亲代与子代携带病毒的情况不完全一致,不能确实白斑综合征病毒可否通过繁殖,在卤虫世代间进行垂直传播,研究结果表明:卤虫很可能是白斑综合征病毒的携带者,苗种培育和养殖期间投喂卤虫可能造成虾,蟹感染白斑综合征病毒,卤虫检疫是培育健康苗种的关键措施。  相似文献   

5.
投保综合险的渔船事故中,由于船体大小不同以及构造的特殊性,出险时查勘人员无法对每一条船进行精确的查勘测量,特别是型宽和型深较长的渔船,这对渔业船舶损失的精确定损、复核计算带来了一定困难。为此,通过对福建省目前渔船理赔过程中查勘定损、复核现状问题进行分析,提出了通过采用图像处理法图像测量损失尺寸大小、手持激光测距仪器以及超声波测厚仪的应用,解决精确测量查勘、复核问题的方法和措施,为渔业保险机构工作人员精确处理查勘定损、复核提供了参考依据,加快理赔速度,提高理赔服务质量,最后提出了两种培养专业人才的方法,解决目前新路径中人才缺乏的问题,为进一步提高理赔服务效率打下坚实的基础。  相似文献   

6.
Cu2+和Cd2+对克氏原螯虾幼虾的毒性效应研究   总被引:3,自引:0,他引:3  
采用静水法生物测试,研究了Cu2+和Cd2+对克氏原螯虾幼虾(体重0 0142~0 0308 g)的急性毒性作用.试验结果表明,克氏原螯虾对Cu2+、Cd2+均会产生较强的毒性效应,其对Cu2+、Cd2+的耐受性随接触时间延长而明显降低.Cu2+对克氏原螯虾幼虾24 h、48 h半致死浓度(LC50)分别为30.854 mg/L、10.595 mg/L;Cd2+对克氏原螯虾幼虾24 h、48 h、72 h半致死浓度(LC50)分别为5.315 mg/L、1.371 mg/L和0.414 mg/L.Cu2+、Cd2+对其的安全浓度(SC)分别为0.375 mg/L、0.027 mg/L,为相应渔业水质标准的3.8倍和 5.5倍,表明克氏原螯虾具有较强耐受Cu2+和Cd2+污染的能力.  相似文献   

7.
淡水青虾立体养殖操作技术   总被引:1,自引:0,他引:1  
淡水青虾学名日本沼虾,因其味道鲜美,营养丰富,深受人们的喜爱,而传统的池塘养殖淡水青虾方式因受到各方面条件的限制,产量商品率及效益都较低。我市通过几年来的试验养殖及进一步的推广实践,成功地总结出了一整套完整的淡水青虾立体养殖技术,使淡水青虾产量较一般的传统养殖方式提高50%五右,技术的突破带动了我市淡水青虾的发展,青虾已经成为我市水产名特优产品中的主要品种。1999年全市淡水青虾专养面积达到9302.7亩、总产商品虾913.05吨,平均亩产981公斤,其中青虾立体养殖面积达到2490亩,总产商品虾323.4吨,平均亩产达1…  相似文献   

8.
猪肺炎支原体致病机理研究进展   总被引:1,自引:0,他引:1  
猪肺炎支原体是引起猪支气管肺炎的主要病原,严重危害着养猪业的发展。文章从猪肺炎支原体的结构、主要抗原蛋白研究及其在基因水平的研究等方面,对猪肺炎支原体的致病机理作一综述,为该疾病的防治提供理论依据。  相似文献   

9.
  1. Human translocations of non-native aquatic species are a global conservation challenge. Aquarists and anglers are two hobbyist groups whose practices are particularly likely to translocate non-native aquatic species, especially fish.
  2. This article aims to stipulate a change of perspective among these hobbyists, who – by acting simultaneously as anglers and aquarists – establish novel pathways for non-native fish.
  3. This study showed that: (i) 51 of 226 respondents to a questionnaire act simultaneously as anglers and aquarists; (ii) 53 of 237 non-native fish species in the European Union are used for both angling and aquarium hobbies; and (iii) hobbyists write online reports on the catch and exchange of a particularly invasive fish, the round goby (Neogobius melanostomus).
  4. This combination of knowledge on how hobbyists use non-native fish and the ecological impacts of round goby demonstrates how the impact of an invasive species can be influenced by the combined behaviours of anglers and aquarists.
  5. We suggest that future research in aquatic conservation should move beyond considering the commercial aquarium trade and angling as separate pathways for translocating non-native fish, and instead consider these hobbyist groups as interconnected.
  相似文献   

10.
Cr6+、Zn2+、Hg2+对凡纳滨对虾幼虾急性毒性和联合毒性研究   总被引:13,自引:0,他引:13  
2004年8月在浙江华兴海水种苗有限公司以养殖日龄40 d的凡纳滨对虾(Litopenaeus vannamei)幼虾作为实验动物,开展了Hg2+、Zn2+、Cr6+对凡纳滨对虾幼虾的急性毒性和加和等毒性强度联合毒性试验.结果表明,Hg2+对凡纳滨对虾幼虾24、48、72、96 h的半致死质量浓度分别为0.415、0.357、0.264、0.209 mg/L;Zn2+对凡纳滨对虾幼虾24、48、72、96 h的半致死质量浓度分别为35.362、22.709、17.041和13.569 mg/L;Cr6+对凡纳滨对虾幼虾24、48、72、96 h的半致死质量浓度分别为40.892、 27.498、 21.635和13.573 mg/L.凡纳滨对虾幼虾对Cr6+、Zn2+、Hg2+ 96 h安全质量浓度分别为0.136、0.136和0.0021mg/L.各重金属离子毒性大小依次为Hg2+>Zn2+≈Cr6+.Hg2+-Zn2+、Hg2+-Cr6+对凡纳滨对虾幼虾的96 h联合急性毒性表现为协同作用.Zn2+-Cr6+对凡纳滨对虾幼虾的96 h联合急性毒性表现为,低毒性强度的Zn2+对Cr6+具拮抗作用,低毒性强度的Cr6+则对Zn2+具加和作用,而当Zn2+与Cr6+毒性强度相当时表现为相互独立作用.并就Hg2+、Zn2+、Cr6+对凡纳滨对虾幼虾的急性致毒效应特征,凡纳滨对虾幼虾对Hg2+、Zn2+、Cr6+的安全浓度以及重金属离子间联合毒性效应进行了分析与探讨.  相似文献   

11.
水产养殖用水估价模型研究   总被引:1,自引:0,他引:1  
水产养殖行业中,水资源利用效率低下,以及环境污染日益增加的主要原因,是水资源稀缺以及环境的消极外部影响的不合理体现所致.根据水产养殖用水的资源特性,水产养殖用水的评价模型已经建立起来了.该模型用水资源影子价格来确定资源水价的比例,用环境外部性来确定环境水价的比例.与此同时,探索和讨论养殖用水评价模型的途径和方法也已经构建起来了.运用水产养殖用水水价估值模型来计算2008年上海淡水池塘养殖用水的价格,其中资源水价部分(P1)为3.07元,环境水价部分(P2)为0.61元,折算系数(r)为0.95,计算得到每吨的价格为3.65元.  相似文献   

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