首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   125篇
  免费   19篇
  国内免费   9篇
综合类   24篇
农作物   1篇
水产渔业   128篇
  2024年   2篇
  2023年   2篇
  2022年   1篇
  2021年   4篇
  2020年   6篇
  2019年   4篇
  2018年   5篇
  2017年   7篇
  2016年   4篇
  2015年   7篇
  2014年   8篇
  2013年   8篇
  2012年   8篇
  2011年   6篇
  2010年   6篇
  2009年   6篇
  2008年   13篇
  2007年   13篇
  2006年   15篇
  2005年   7篇
  2004年   6篇
  2003年   6篇
  2002年   1篇
  2001年   4篇
  2000年   2篇
  1997年   2篇
排序方式: 共有153条查询结果,搜索用时 328 毫秒
1.
磁珠富集法制备大口鲶的微卫星分子标记   总被引:3,自引:0,他引:3  
全迎春 《水产学报》2006,30(3):335-340
2004年3月16日-6月8日,在广东广远渔业集团有限公司玻璃钢大滚筒冷海水金枪鱼延绳钓渔船“华远渔19”号,对印度洋马尔代夫海域进行金枪鱼渔业调查。所获数据资料包括:①CTD测定的温度、盐度和深度数据,TDR测定的实际钩深;②作业参数,包括每次作业的钩数、投绳位置、投绳时间、航向、航速、出绳速度、两浮子间的钩数、起绳位置、起绳时间等;③渔场环境数据,包括风速、风向、钓具对地漂移速度和方向;④渔获统计,包括大眼金枪鱼的渔获尾数以及部分大眼金枪鱼的钓获钩号;⑤生物学数据,包括起捕时已死的大眼金枪鱼的体温。分析计算的方法和步骤为:①由理论公式推算出每次作业时各钩号的理论深度;②应用逐步回归的方法,建立理论钩深与实测的平均钩深之间的数学关系模型;③根据实际平均钩深模型计算出每个钓钩的平均作业深度;④根据CTD测得的作业地点的温度、盐度的垂直分布(41次),获得分布曲线。由此,以计算的钩深,从曲线上查出该尾鱼捕获水深处的温、盐数据;⑤根据121尾大眼金枪鱼的取样数据,推算出各水层、水温段、盐度段的渔获率;⑥根据起捕时已死的34尾大眼金枪鱼(鱼体发硬)的体温、以死鱼体温为引数,在曲线上查出该尾鱼捕获水深和盐度;最后,对钓获的大眼金枪鱼的钓获水层、水温和盐度进行了总体分析。分析结果表明:在马尔代夫海域,捕获大眼金枪鱼的水层为50~210m、水温范围为13.0~29.9℃、盐度范围为35.00~35.79;渔获率最高的水层为70~90m、水温范围为27.0~27.9oC、盐度范围为35.70~35.79;捕获时已死鱼的捕获水层、水温和盐度推算数据为63~203m、14.0~27.0℃和34.94~35.42,主要集中在63~134m、16.0~27.0℃和35.30~35.42。  相似文献   
2.
摘要:2001年7月4日-10月27日,中国水产总公司所属的3艘大洋性超低温金枪鱼延绳钓渔船对大西洋中部公海海域进行金枪鱼渔业调查。本文根据所获得的渔场环境、作业参数、渔获统计等数据,应用栖息地适应性指数(habitat suitability index, HSI)模型并结合分位数回归分析方法分别对有关水层(60m为一层)及总渔获率与温度、盐度和相对流速等环境因素的关系并考虑其不同的影响权重及交互作用建立了数值模型,根据该模型计算大眼金枪鱼的栖息环境综合指数(HEII),利用MarineExplore4.0绘制大眼金枪鱼HEII指数等值线分布图。结果显示:(1)180~240m水层中,中部海区的 指数分布较高(高于0.6),其他海区分布较低(小于0.6);(2)240~300m水层中,6ºN以南的海区 分布较高(高于0.6),以北的海区分布较低;(3)300~360m水层中,仅南部部分海区(4ºS,23ºW附近) 分布较高,其他大部分海区分布很低(低于0.3);(4)7ºN以南的大部分海区 指数分布较高(高于0.6),仅在部分较小海区(5ºN,22ºW、2ºS,17ºW和2ºS,23ºW的附近)内 指数分布低于0.5。 关键词:大眼金枪鱼;栖息环境综合指数;分位数回归;大西洋中部公海  相似文献   
3.
印度洋东部黄鳍金枪鱼的渔业生物学   总被引:7,自引:0,他引:7  
根据在印度洋东部海域的延绳钓生产实践 ,对所渔获的黄鳍金枪鱼 (Thunnus albacares)群体的构成、繁殖等基本生物学特征进行了初步探讨。结果显示 ,渔获黄鳍金枪鱼纯重范围为 10~75 kg,叉长范围为 80~ 15 0 cm,纯重、叉长关系为 W=1.5 2 7× 10 -5L3,渔获构成月间变化明显 ,不同年龄个体性成熟与繁殖节律差异显著  相似文献   
4.
A land-based culture facility for research on yellowfin tuna, Thunnus albacares, was developed at the Achotines Laboratory in the Republic of Panama. Six concrete tanks, and seawater and life support systems were built to maintain a yellowfin broodstock. On average, 50% of the yellowfin caught survived capture and handling, and approximately 30% became broodstock in Tank 1 (17 m diameter, 6 m depth) or Tank 2 (8.5 m diameter, 3 m depth). Each fish was tagged with a microchip implant tag, then weighed, measured, and injected with oxytetracycline (OTC) prior to stocking. Daily rations of primarily market squid, Loligo opalescens, and Pacific thread herring, Opisthonema spp., were regulated based on the feeding activity and energy requirements of the fish. Feeding activity of the broodstock decreased when the water temperatures decreased, and the fish ate decreasing daily rations and increasing calories with increasing size. Spawning occurred in both tanks within 6–8 months of capture. Spawning first occurred in Tank 1 when 24 females ranged in size from 6 to 16 kg and 65 to 93 cm fork length (FL). Spawning was intermittent during the first 2 months and occurred near daily thereafter. Tank size appeared to affect survival rates, the types of mortalities that occurred, and the growth of the fish. Survival rates after 1 year in captivity were higher, and the fish were larger, on average, in Tank 1 than in Tank 2. Most of the mortalities in Tank 1 were the result of wall strikes, which occurred more frequently after the fish reached their highest density of 0.64 kg m−3 and sizes greater than 96 cm FL and 19 kg. Non-linear growth models were fitted to the initial stocking sizes and final sizes of fish that died or were removed from Tank 1 during 1996–1999. Estimated growth rates in length (11–48 cm year−1) for fish between 51 and 150 cm FL decreased with increasing length. Estimated growth rates in weight ranged from 9 to 19 kg year−1 for fish less than 19 kg and 20–23 kg year−1 for fish greater than 19 kg. The results of this work demonstrate that the stable environment of a land-based culture facility may be the preferred system for long-term maintenance of a yellowfin broodstock.  相似文献   
5.
应用栖息地指数对印度洋大眼金枪鱼分布模式研究   总被引:10,自引:0,他引:10  
冯波  陈新军  许柳雄 《水产学报》2007,31(6):805-812
运用分位数回归方法对温度、温差、氧差与印度洋大眼金枪鱼延绳钓钓获率进行二次回归分析,找出最佳上界方程,以最佳上界方程拟合的数值来建立栖息地指数(HSI)模型,从而揭示印度洋大眼金枪鱼栖息地的分布模式。研究表明,温度、温差、氧差与印度洋大眼金枪鱼延绳钓钓获率的最佳上界分位数回归方程分别为HR_(T0.9)=-44.803 7.685T_(0.9)-0.255T_(0.9)~2,HR_(dT_(0.9))=6.234 0.953dT_(0.9)-0.026dT_(0.9)~2和HR_(dO_(0.88))=7.422 4.25dO_(0.88)-0.727dO_(0.88)~2。10°N~10°S间印度洋海域大眼金抢鱼HSI指数达到0.9以上;10°N以北的波斯湾及10°S~15°S海域的HSI指数为0.8~0.9;15°S~40°S之间海域HSI指数介于0.7~0.8,其中50°E~90°E、15°S~25°S间存在一片季节性HSI指数<0.7的区域;40°S以南的海域HSI指数<0.6。  相似文献   
6.
7.
ABSTRACT:   The feeding habits of albacore Thunnus alalunga (fork length: 48.9–76.2 cm, n  = 132) were examined from late spring to early autumn in relation to its northward migration in the transition region between the subtropical and subarctic fronts in the central North Pacific. Samples were collected at night using surface gill nets or during daytime pole-and-line surveys in 2001 and 2002. During May and June, albacore fed mainly on Japanese anchovy Engraulis japonicus , which accounted for 27.2%, 67.0%, and 45.5% of the total stomach contents by number ( Cn ), wet weight ( WW ), and frequency of occurrence ( F ), respectively, and secondarily on the subarctic gonatid squid Gonatopsis borealis ( Cn , 15.8%; WW , 10.8%; F , 28.8%). From July to September, albacore continued to depend on Japanese anchovy ( Cn , 48.2–52.8%; WW , 79.9–95.2%; F , 27.8–85.4%). These results corresponded well with the remarkable rebound of the Japanese anchovy stock since the 1990s. Gonatopsis borealis , the main squid prey from May to June, almost disappeared from the stomachs of albacore from July to September, probably due to the northward migration of this squid to subarctic waters in summer. The feeding impact of albacore on the Japanese anchovy stock in the transition region was conservatively estimated to be from 1400 to 2100 tons per day from late spring to early autumn.  相似文献   
8.
Fishery‐linked aerial surveys for bluefin tuna (Thunnus thynnus) were conducted in the Gulf of Maine (GOM) from July through October, 1994–96. Each year, from 507 to 890 surface schools were detected and their locations examined in relation to oceanographic conditions. Correlations between bluefin tuna presence and environmental variables were explored for sea surface temperature (SST), distance to a SST front, frontal density (relative density of all SST fronts seen in a given 1 km area for 2 weeks prior to each tuna sighting), and bottom depth and slope. Mean SST associated with bluefin schools was 18.1°C (±2.8). Schools were located at a mean distance of 19.7 km (±19.6) from SST fronts, and in water masses with an average frontal density of 28.2 m km?2 (±35.7). Mean bottom depth of detected schools was 139.0 m (±70.3), and mean bottom slope was 0.7% rise (±0.7). A binomial generalized linear model fit to these variables indicated that bluefin are seen closer to fronts than locations in which no tuna were seen. Using simple and partial Mantel tests, we investigated the spatial correlation between bluefin tuna presence and the environmental variables, controlling for spatial autocorrelation. For each day that schools were sighted, we performed 24 Mantel tests, on a combination of response and predictor variables. The spatial relationship between bluefin tuna and SST fronts was inconsistent. Our analysis identified significant spatial structure in the bluefin school locations that had no significant correlation with any of the measured environmental features, suggesting that other untested features, such as prey density, may be important predictors of bluefin distribution in the GOM.  相似文献   
9.
  1. Although the frequency of occurrence of plastic ingestion in the large-sized dolphinfish and tunas taken by the Hawai'i longline fishery is very low (frequency of occurrence < 5% of sampled individuals), the ingestion of plastic in smaller-sized specimens caught with pole-and-line gear by commercial and recreational fishers has not been investigated.
  2. This study examined ingestion of >0.25 mm marine plastic debris (MPD) by four predatory fish species caught by commercial fishers around the Main Hawaiian Islands, and documented ingestion in three species: 85.7% of albacore tuna (n = 7), 40.0% of skipjack tuna (n = 10) and 12.5% of dolphinfish (n = 8).
  3. Yellowfin tuna (n = 10) did not contain any MPD, probably owing to the high proportion of empty stomachs (60%).
  4. For skipjack tuna, the frequency of occurrence of MPD ingestion was significantly higher for the smaller-sized specimens caught with pole-and-line (40%), compared with the larger-sized specimens caught with longlines (0%).
  5. For dolphinfish, the frequency of occurrence of MPD ingestion was similar for the similar-sized specimens caught with pole-and-line and with longlines.
  6. The ingested MPD items were micro–meso plastics, between 1 and 25 mm. While most ingested items were fragments, albacore also ingested line and skipjack also ingested sheets.
  7. The predatory fishes ingested light MPD items that float in sea water, but there were species-specific differences in their polymer composition: albacore contained more polypropylene and polyethylene, and skipjack contained more elastomers, characterized by a high percentage of ester plasticizers.
  8. Altogether, these results suggest that albacore and skipjack tunas ingest plastic of different types and polymers. Yet more research is needed to understand how differences in vertical distribution, foraging ecology and diet influence the MPD sampled by these predatory fish species.
  相似文献   
10.
地中海金枪鱼延绳钓渔获物组成的初步分析   总被引:3,自引:0,他引:3  
本文对1995年5月-6月、1996年4月下旬-7月初地中海金枪鱼延绳钓汛期间渔获物组成进行初步分析。结果表明主要渔获物种有蓝鳍金枪鱼、箭鱼、大青鲨、翻车鱼、龟、极少见的鱼种有尖吻青鲨、长鳍金枪鱼、叉尾长鳍乌舫以及肛科的一种肛。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号