Habitat utilization and vertical movements of white marlin (Tetrapturus albidus) released from commercial and recreational fishing gears in the western North Atlantic Ocean: inferences from short duration pop-up archival satellite tags

Researchers have applied numerous techniques to improve billfish stock assessments, including habitat‐based models that incorporate behavioral and oceanographic parameters to standardize historical catch‐per‐unit‐effort time‐series data. These methods have allowed researchers to account for significant changes in the depths of pelagic longline (PLL) gear deployments over time. This study presents habitat‐use data recovered from high‐resolution 5‐ and 10‐day pop‐up satellite archival tags (PSATs) attached to 47 surviving white marlin released from commercial and recreational fishing gears offshore of the U.S. East Coast, the northern Caribbean, and Venezuela between 2002 and 2004. Data recovered from transmitting tags indicated that white marlin spent nearly half of their time associated with warm, near‐surface waters (<10 m). All fish displayed frequent short duration (mean: 39.8 min) vertical excursions from surface waters to depths averaging 51 m. Qualitative and multivariate classifications of data from completely transmitted movements of surviving white marlin revealed two major types of descents: one pattern was characterized by deep ‘V’‐shaped excursions of relatively short duration (mean: 23.4 min) while the other featured descents that were more broadly ‘U’‐shaped and confined to a specific depth range for an extended period of time (mean: 75.8 min). Based on the frequency, persistence, and patterns of these vertical movements, white marlin appear to direct a considerable proportion of foraging effort well below surface waters, a behavior that may account for relatively high catch rates of white marlin on some deep‐set PLL deployments.     

ASP.net中的SQL查询技巧及应用

ASP.net是微软公司推出的新一代网站程序开发框架,是.net框架提供的一个统一的Web开发模型。利用ASP.net技术可以方便开发动态网站,而在网站开发中数据查询占据很大的比例。     

中文数据库水产文献资源分析

本文对我国 3个主要中文数据库文献资源以及水产文献收录量进行了统计分析。中国水产科学研究院信息研究中心开发的中国水产文献数据库目前共有记录 5 7196条 ,起始于 1983年。重庆维普资讯有限公司开发研制的中文科技期刊数据库中收录水产类记录 394 4 4条 ,清华同方公司的中国学术期刊光盘数据库收录水产类记录 3592 7条。中国水产文献数据库收录的水产文献量及时间跨度最大 ,是获取水产文献信息的首选数据库。维普库和同方库同样是我国重要的水产文献信息源。这三个数据库在水产文献信息服务中发挥了重要作用。虽然三库存在一定程度的交叉重复 ,但也存在着不同程度的互补性 ,并且在收录期刊和文献方面各具特色     

Development of buffer methods and evaluation of pedotransfer functions to estimate pH buffer capacity of highly weathered soils

The pH buffer capacity of a soil (pHBC) determines the amount of lime required to raise the pH of the soil layer from its initial acid condition to an optimal pH for plant growth and the time available under current net acid addition rate (NAAR) until the soil layer acidifies to a critical pH leading to likely production losses. Accurate values of pHBC can also be used to calculate NAAR from observed changes in soil pH. In spite of its importance, there is a critical shortage of pHBC data, likely due to the long period of time needed for its direct measurement. This work aimed to develop quick, simple and reliable methods of pHBC measurement and to test these methods against a slow (7‐day) titration used as benchmark. The method developed here calculates pHBC directly from the pH buffer capacity of the buffer solution and the increase in soil pH and corresponding decrease in pH of the buffer solution following mixing and equilibration. The pHBC values calculated using Adams and Evans or modified Woodruff buffers were in accord with those measured by slow titration. Buffer methods are easily deployed in commercial and research laboratories as well as in the field. The advantage of using buffer solutions to calculate pHBC instead of lime requirement is the broad application of this soil property. The pHBC of a soil is an intrinsic property that would not be expected to need remeasurement over periods of less than decades. Recurring lime requirement can be calculated from the soil's pHBC, initial and target pH values. A large proportion of the variability in pHBC was explained by the soil organic carbon content. This relationship between pHBC and soil organic carbon content allowed us to develop local pedotransfer functions to estimate pHBC for different regions of Australia.     

闽南海区休渔前后张网作业渔获物组成比较分析

本文主要根据2008年闽南海区张网作业渔业资源监测资料，对休渔前后（4月和8月）张网作业渔获物组成进行比较分析。结果表明：2008年休渔前后都以捕经济种类幼鱼为主。4月带鱼、二长棘鲷、刺鲳、鲐鱼、中华管鞭虾等主要经济种类渔获重量占总渔获物重量69．6％，其中带鱼幼鱼数量最多，占总渔获数量的26．2％（每网渔获尾数744ind），居第一位；且个体极小，基本上全为幼鱼，平均体重8．1g。8月带鱼、二长棘鲷、短尾大眼鲷、叫姑鱼、白姑鱼、须赤虾等主要经济种类渔获重量占总渔获物重量50．9％。带鱼数量明显减少（每网渔获尾数226ind），但个体增大，肛长140mm以上占63．6％，平均体重54．5g，比4月增加46．4g。并结合2004、2007年有关资料，较为详细说明休渔前（4月）张网作业对近岸经济幼鱼、幼体损害比休渔结束后（8月）严重，通过休渔对带鱼等经济种类幼鱼资源起了一定保护作用。     

Analysis of mesh breaking loads in cotton gill nets: Possible solution to ghost fishing

ABSTRACT:   A small number of fishers in Chiba Prefecture of eastern Japan use cotton gill nets to catch Japanese spiny lobster Panulirus japonicus. To examine the advantages of cotton gill nets, we analyzed changes in mesh breaking load of a new cotton gill net used in a fishing operation. A new cotton gill net was also soaked in a seawater tank to simulate ghost fishing conditions. The average mesh breaking load of new cotton mesh was 50.3 N. This value decreased to 19.0 N after 38 days (∼912 h), and after 82 days (∼1968 h) the mesh could be easily torn (breaking load 0.07 N). Under fishing conditions, the cumulative soak time was only 744.4 h over 19 months. The average breaking load at the end of this period was 43.1 N, a strength 86% that of the presoaked mesh. The mesh breaking load of a cotton gill net continuously soaked for 744.4 h was 26.1 N, as estimated from tank experiment data. Thus, a cotton gill net maintains reasonable strength under typical use conditions, but will degrade if lost at sea.     

辽宁节约型渔业发展战略研究

节约型渔业发展战略是辽宁渔业可持续发展的基本战略。其研究不仅具有经济意义，而且具有社会、生态意义。文章阐述了发展节约型渔业的意义和节约型渔业与传统渔业的区别；分析了辽宁发展节约型渔业的障碍；提出了辽宁节约型渔业发展战略措施。     

Distribution and migration of Japanese common squid, Todarodes pacificus, in the southwestern part of the East (Japan) Sea

Data on squid catches of Korean and Japan, water temperatures at depth of 100 m, and night-visible images of fishing boats collected in the East (Japan) Sea from 1970 to 1999 were analyzed to examine the distribution and migration of the Japanese common squid, Todarodes pacificus, in the southwestern part of the East (Japan) Sea. The main fishing grounds detected from squid catch in each grid (0.5° latitude × 0.5° longitude) by Korean squid fishery and night-visible images provided by the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS) were situated in the southwestern part of the East (Japan) Sea. The distribution and migration route was illustrated from squid catch in each grid and DMSP OLS image. In years of high catches, the fishing grounds were situated mainly between Ulleung Island and the eastern coastal waters of Korea, while in years of low catches they were situated between Ulleung Island and the Yamato Bank in the central East (Japan) Sea. The center of fishing activity began moving northward from around the Korea/Tsushima strait to the northern boundary of the Tsushima Warm Current in March, reaching into the Yamato Bank in September, and then returning to the strait by February. The northward and southward migration routes differed; the northward migration route occurred closer to the mainland coast of Korea than the southward migration route did. This work suggests T. pacificus begin their northward migration almost 2 months earlier than previously suggested.     

微电脑在二片式对拖网设计上的应用及捕捞效果分析

本文分析了二片式对拖网设计软件设计的基本原理及渔获效果的对比。结果表明,本软件设计先进、科学,具有良好的适用性、精确性、高度灵活性和快速简便性等优点;利用本软件设计的网具,具有良好的渔获效果。     

校园网ARP病毒的应对与防范

如何防范与应对ARP病毒现已成为摆在各校园网网络管理者面前的一个厄待解决的技术难题。本文阐述了ARP协议工作的原理，分析了ARP病毒攻击过程，剖析了ARP病毒对网络的危害，并结合校园网络的架构特点给出了ARP病毒防范与应对的方法。