东海区海洋渔业资源研究数据库系统的设计和实现

在系统收集东海区历年海洋捕捞产量、捕捞努力量统计资料、主要经济鱼类生物学参数以及渔业资源研究文献报告题录等资料基础上，对数据资料进行整理和补充，建成了渔业资源研究数据库。利用Ｂａｓｉｃ语言编程实现渔业资源评估、产量预报、回归分析、判别函数分析等数据处理、分析功能。通过Ｆｏｘｐｒｏ编程和ＡＰＩ接口，实现对数据库的管理和对数据处理功能的调用，形成了东海区海洋渔业资源研究数据库系统，系统提供数据的输入、     

东海区渔业资源的区域合作管理与共同养护研究

一、东海区渔业资源区域合作管理与共同养护的必要性长期以来,由于东海区集中了强大的捕捞能力,对渔业资源的捕捞量超过了其再生能力,导致资源总体上出现严重衰退。主要表现为:鱼类个体小型化、低龄化和性早熟现象非常明显;渔获物中传统经济鱼类的比例下降,低龄鱼、低质鱼和杂鱼成为了主要的捕捞对象;单位捕捞努力量渔获量(Catch per unit effort,CPUE)下降,渔获物的平均营养级降低。说明有必要加强对东海区渔业资源的养护与管理,减少对资源的开发力度。中、日、韩三国作为共同开发利用东海区渔业资源的国家,理应承担起养护和管理东海区渔…     

东海区拖虾渔业概况分析

虾类是东海区的主要捕捞对象之一。东海区的拖虾渔业以虾类为主要捕捞目标,发展之初对于促进捕捞结构调整、减轻主要经济鱼类的捕捞压力起了重要作用。但是随着该种作业方式生产规模的不断扩大、生产渔船和渔具的大型化,渔获物中经济虾类和兼捕幼虾的矛盾日益突出,对东海区的渔业资源造成较大程度的破环。本文主要介绍了东海区拖虾渔业的发展和资源概况,主要经济虾类的种类、分布、作业渔船的产量和数量变化,分析了东海区拖虾渔业中存在的问题和所采取的措施,并提出了解决问题的建议。     

东海区伏季休渔渔业生态效果的分析研究

以１９９０ ～１９９８ 年我国东海区的海洋渔业统计资料和渔业资源动态监测资料为依据,分析研究１９９５ ～１９９８ 年伏季休渔对东海区渔业生态效果的影响。结果表明,带鱼等主要经济鱼类的产卵群体得到了有效保护;经济幼鱼的渔获比例及其资源密度指数有所提高,幼鱼群体养护效果也较明显;渔获个体的生物学特征值具有转好的趋势;主要经济鱼类资源生物量明显增加;渔业资源的种间结构得到一定程度的改善;年渔获产量明显增加,单位捕捞努力量渔获量（ＣＰＵＥ） 有所提高。     

东海区底拖网渔业资源变动分析

以2000~2005年底拖网渔业资源的常规监测资料为依据,对东海区底拖网渔获物种类组成、主要经济鱼种单位捕捞努力量渔获量(CPUE)以及生物学特征进行了分析。结果表明,东海区底拖网渔业资源利用结构正在向低值和低营养层次鱼种转化,主要经济鱼种的CPUE不断下降,生物学特征未见明显好转,而渔获物中幼鱼比例不断上升,渔业资源总体状况仍然存在继续衰退趋势。建议降低目前的海洋捕捞努力量,延长伏季休渔时间,加强渔业资源养护和管理力度等。     

东海区海洋渔业资源及其作业结构特点的分析

东海区渔业行政地理位置北起35°05′N南至22°OO′N，西临我国大陆，东至200m等深线，是西北太平洋西部一个较开阔的边缘浅海，大陆架渔场面积约5729k－m’，约占我国海域陆架总面积的3876％Q由于长年受黑潮暖流、大陆架沿岸流的混合交替作用，东海区陆架渔场一直是我国沿海资源蕴藏量最丰富的海域。渔业资源品种繁多，计有鱼类近7O0种、虾蟹类15O多种、头足类6O多种，其中主要经济渔业资源鱼类有19种、头足类2种、虾蟹类13种、水母1种，1998年海洋捕捞产量约占全国海洋捕捞量的42％。针对渔业资源繁多的特点，东海区的作业方式也是多…     

东海区主要渔业资源利用状况的分析

本文根据东海区渔业资源调查和区划、东海大陆架生物资源与环境和全国渔业统计年鉴等资料,统计1956~2002年东海区捕捞品种中经济价值较高、在渔业中占重要地位的11个种类的产量,并利用数理统计学上的主成分分析方法,分析研究了东海区11个主要捕捞种类历年来的资源变动特征、资源利用状况及其变动趋势。结果表明:11个主要捕捞种类的渔业资源状况可分为3种类型,分别为过度捕捞已严重衰退的资源、充分利用并开始衰退的资源和尚有潜力的资源,其中大黄鱼、鳓鱼资源已进入资源衰退期,带鱼、鲐鲹鱼类、墨鱼和小黄鱼等处在充分利用并开始衰退期,虾蟹类、鲳鱼、马鲛鱼、鲷科鱼类和海鳗等资源尚有潜力。     

鄱阳湖渔业资源现状与养护对策研究

鄱阳湖是我国第一大淡水湖,渔业资源十分丰富,有鱼类136种,占长江鱼类种数的36.76%、江西鱼类种数的66.34%。近年来,鄱阳湖渔业资源衰退明显,主要表现为捕捞产量逐年下降,渔获物种类减少,小型定居鱼类和低龄鱼比例上升。笔者对鄱阳湖2000-2006年渔业资源变化及原因进行了分析,并从加强资源监测、养护技术研究,修复渔业生态环境等方面提出了保护的措施建议。     

解决过度捕捞的办法:培训渔民

70年代中后期以来，我国乃至全世界的海洋渔业资源均在衰退，海洋捕捞业面临的危机趋于增大。这一局势已引起了世界渔业管理部门的极大关注，也制定出许多渔业资源管理法现、条例和实施细则，但至今收效甚微。海洋渔业资源衰退的成因很多，过度捕捞就是其中之一。许多迹象表明，当前我国浅、近海底渔业资源基本上已被充分利用，有些传统经济鱼类资源已经捕捞过度。可以这么说，过度捕捞的责任主要在于渔业生产单位和渔民。一些生产单位往往以高产为荣，拼命追求产量第一，从而盲目发展捕捞工具，增加捕捞强度，使海洋渔业资源受到了严重的破…     

2004年夏季东海区带鱼资源状况及其秋冬汛渔况的分析

东海带鱼为我国最重要的捕捞对象之一，其产量多年来一直位居我国海洋捕捞鱼类产量的首位。由于6月～9月是东海带鱼的繁殖与索饵盛期，因此，自1995年以后伏季休渔制度实施以来，每年的伏季休渔期间，带鱼群体得到了有效的生长和补充，伏季休渔结束后，渔获产量显著提高。本文以东海区渔业资源动态监测调查资料为依据，对2004年东海区伏季休渔期间带鱼资源状况进行了分析，并预测了秋冬汛的带鱼生产趋势。一、研究材料与方法利用1999年～2004年东海区渔业资源动态监测网重点渔场的常规监测和大面定点调查的资料，对历年的夏季带鱼资源密度、…     

南海北部湾2012年捕捞产量估算

南海北部湾是广西、广东和海南三省区渔民的传统重要渔场之一,准确掌握北部湾捕捞产量对于搞好北部湾渔业生产管理意义重大。文章采用2012年南海捕捞信息动态采集网络的广西渔船生产数据,参考广西相关渔业调查资料,分别推算2012年广西拖网、围网、刺网、钓具、定置网和其他杂渔具在北部湾的捕捞产量,统计广西全年在北部湾的捕捞产量为39．2×10^4t,进而推算中国渔船2012年在北部湾的产量为65．7×10^4t。在此基础上,再采用相关文献中有关越南渔船在北部湾的产量,估算2012年北部湾的捕捞产量约为85．7×10^4t。     

Effect of towing speed and net mouth size on catch efficiency in framed midwater trawls

ABSTRACT:   To investigate fish density using rigid-mouth, towed net gear, such as a framed midwater trawl (FMT), it is necessary to know the catch efficiency. The catch efficiency with an FMT is described as the rate of fish entering the net (entering rate) versus the rate of fish retention, i.e. the mesh selectivity. This study investigated the change in the catch efficiency under several towing conditions using three types of FMT of different net mouth areas (4.0, 12.3, and 16.0 m²) with the same mesh size. The catch efficiency of the FMT was evaluated by comparing catch per unit effort obtained from each towing condition. The catch efficiency of FMT varied with towing speed and net mouth area. Particularly, the effect of net mouth area on the catch efficiency was greater than that of towing speed. Additionally, under the same towing condition, the catch efficiency for large length fish was lower than that for small length fish.     

Effort rights‐based management

Effort rights‐based fisheries management (RBM) is less widely used than catch rights, whether for groups or individuals. Because RBM on catch or effort necessarily requires a total allowable catch (TAC) or total allowable effort (TAE), RBM is discussed in conjunction with issues in assessing fish populations and providing TACs or TAEs. Both approaches have advantages and disadvantages, and there are trade‐offs between the two approaches. In a narrow economic sense, catch rights are superior because of the type of incentives created, but once the costs of research to improve stock assessments and the associated risks of determining the TAC and costs of monitoring, control, surveillance and enforcement are taken into consideration, the choice between catch or effort RBM becomes more complex and less clear. The results will be case specific. Hybrid systems based on both catch and effort are increasingly employed to manage marine fisheries to capture the advantages of both approaches. In hybrid systems, catch or effort RBM dominates and controls on the other supplements. RBM using either catch or effort by itself addresses only the target species stock externality and not the remaining externalities associated with by‐catch and the ecosystem.     

Effect of fishing effort on catch rate and catchability of largemouth bass in small impoundments

Largemouth bass Micropterus salmoides (Lacepède) catch rates decline with sustained fishing effort, even without harvest. It is unclear why declines in catch rate occur, and little research has been directed at how to improve catch rate. Learning has been proposed as a reason for declining catch rate, but has never been tested on largemouth bass. If catch rate declines because fish learn to avoid lures, periods of no fishing could be a management tool for increasing catch rate. In this study, six small impoundments with established fish populations were fished for two May to October fishing seasons to evaluate the effect of fishing effort on catch rate. Closed seasons were implemented to test whether a 2‐month period of no fishing improved catch rates and to determine whether conditioning from factors other than being captured reduced catch rate. Mixed‐model analysis indicated catch rate and catchability declined throughout the fishing season. Catch rate and catchability increased after a 2‐month closure but soon declined to the lowest levels of the fishing season. These changes in catch rate and catchability support the conclusion of learned angler avoidance, but sustained catchability of fish not previously caught does not support that associative or social learning affected catchability.     

Spatio‐temporal management of fisheries to reduce by‐catch and increase fishing selectivity

Time/area closures have been widely used in fisheries management to prevent overfishing and the destruction of marine biodiversity. To a lesser degree, such spatio‐temporal management measures have been used to reduce by‐catch of finfish or protected species. However, as ecosystem‐based management approaches are employed and more fisheries are managed through multispecies, multiobjective models, the management of by‐catch will likely become increasingly important. The elimination of by‐catch has become a primary goal of the fishing policies of many countries. It is particularly relevant in the United States, as the deadline for setting annual catch limits (ACLs) in all fisheries passes in 2011. This will result in a dramatic expansion of the number of catch and by‐catch quotas. Such catch measures may result in the early closure of otherwise sustainable fisheries when by‐catch quotas are exceeded. To prevent such closures and the consequent economic hardship to fishers and the economy, it is imperative that managers be given the tools necessary to reduce by‐catch and improve fishing selectivity. Targeted spatio‐temporal fishery closures are one solution open to managers. Here, we examine how the spatio‐temporal and oceanographic characteristics of by‐catch may be used by managers to design fishery closures, and place these methods within a decision tree to assist managers to identify appropriate management measures. We argue that the current movement towards marine spatial planning (MSP) presents an important impetus to examine how we manage fisheries spatially, and we offer a first step towards the objective participation of fisheries in the MSP process.     

塘沽上岸渔获物组成变化趋势分析

通过对比2006-2007与1998-2000年天津市塘沽区渔业产量及组成发现,10年间总渔获量呈上升趋势,2007年渔获总产量接近1.3万t,鱼类取代虾类,成为主要渔获物.小黄鱼产量明显上升,2007年产量2 436.0 t,是1999年的23倍,虾蟹类产量最多的口虾蛄仅为1999年的27.7％.2007年杂鱼产量有...     

应用分层抽样技术估计北部湾底拖网渔业产量

传统的按行政单元逐级上报的渔业产量调查方法在数据获取过程中受人为因素的干扰,而全面普查的方法受限于时间和经费,相比而言,抽样调查是一种科学合理的方法。本研究于2007年8月对北部湾底拖网产量进行了调查,以全体底拖网渔船为抽样总体,按功率段划分了抽样层次,按比例分配了抽样单元数,分别以生产渔船总数和总功率数推算总产量,并比较了这两种方法的方差。结果表明,用每kW平均产量估计总产量的变异系数为1.13%,用单船平均产量估计总产量的变异系数为14.65%。同时由于渔业抽样调查的难点在于总体船数的掌握,建议统计推断时,采用单位渔捞努力量渔获量（CPUE）推算总体渔获量。     

Baseline assessment of total fisheries-related biomass removal from Japan’s Exclusive Economic Zones: 1950–2010

The rise and fall of Japan’s marine fisheries have been well documented and are clearly evident in official landings statistics. However, the extent of illegal, unreported and unregulated fisheries, including recreational fisheries, and the discarding of unwanted catch in Japanese waters, both of which may have significant implications on the success of management regimes, have yet to be closely examined. This study reassessed the impact of fisheries on the marine ecosystems of Japan’s Exclusive Economic Zones (EEZ) by estimating the total marine biomass removed through the use of an established catch reconstruction approach. Since 1950, 368 million t of marine biomass have been extracted from the Japanese EEZ as commercial catch, recreational catch, illegal catch and discards. Commercial catch accounted for 87 % of the total, while discards accounted for an additional 8 %. The disparity between the estimated biomass removals and the reported commercial catch is 48 million t, or 15 % of the reported catch. The difference is not as large as observed in similar studies of other regions. Nonetheless, the reconstructed biomass removals represent a better baseline for the management of fisheries in the Japanese EEZ, particularly if Japan is to move forward with implementation of output control management.     

以灰色系统理论 (GM) 模型为基础构建印度洋捕捞渔获量预测模型

为了建立捕捞渔获量预测模型，实验利用2000—2016年印度洋渔获量数据，采用灰色系统理论方法，分析了影响其总渔获量的主要渔获类别，建立多种GM模型(Grey model)并进行比较，同时利用2017年与2018年的数据进行验证，得到的最优GM模型用来预测2019—2025年印度洋总捕捞渔获量。结果显示，影响印度洋总渔获量的主要类别有底层鱼类、甲壳类、中上层鱼类、其他海洋鱼类和头足类，其灰色关联度均在0.70以上，经过筛选得到的最优预测模型为GM (1, 5)和GM (1, 6)，平均相对误差分别为1.83%和1.90%，灰色关联度均在0.9以上。2017年和2018年预测平均相对误差分别为3.78%和3.42%。2019—2020、2021—2025年印度洋总渔获量预测值分别为1 186万～1 290万t、1 227万～1 324万t，其主要渔获量增加可能来自中上层鱼类、头足类以及底层鱼类等。研究表明，2021—2025年印度洋总渔获量的增长幅度有限，总增长量在80万t以内，基本处于充分开发阶段，建议未来应严格控制渔业发展规模，确保印度洋海洋渔业的可持续发展和渔业资源可持续利用。     

西南大西洋鱿钓作业渔获物——阿根廷滑柔鱼生物学分析

本文通过海上生产调查分析了西南大西洋鱿钓作业渔获物-阿根廷滑柔鱼的生物学特性。结果表明：⑴公海渔场3月前后的渔获物的雌雄比例、性成熟度、盼望生渔获物性成熟个体体长方面都有所不同，据此推测3月前后公海渔场的阿根廷滑柔鱼可能分属两个不同的种群，1-2月以SSS种群的个体为主，3月后则为SPS种群的个体代替；福克兰渔场渔获物的雌雄比例、性成熟度和雌性渔获物成熟个体体长情况表明福克兰渔场的阿根廷滑柔鱼群体和公海渔场3月后的群体同属SPS种群。⑵体重测定的结果表明渔获物的个体大小随时间的推移逐渐变大，生产者应据此在不同的渔汛阶段调整对钓钩和钓线的使用。⑶阿根廷滑柔鱼主要在夜间捕食，尤其以黄昏刚入夜和黎明前为主，生产者应注意对昼夜间生产时间的把握。