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1.
为了探明南海北部虾拖网副渔获的种类组成、优势种类和幼鱼比例等情况,2012年8月1~5日作者于湛江近海进行了虾拖网副渔获调查。结果表明:湛江近海虾拖网副渔获种类极多,副渔获物与虾类的质量比为3.9:1;副渔获物的主要种类为蟹类和鱼类;蟹类副渔获物的优势种类分别为红星梭子蟹(Portunus sanguinolentus)、三疣梭子蟹(Portunus trituberculatus)和远海梭子蟹(Portunus pelagicus),其相对重要性(IRI)分别为7558.72、6540.72和2826.41;鱼类优势副渔获物的种类分别为褐斑三线舌鳎(Cynoglossus trigrammus)、少鳞鱚(Sillago japonica)、多齿蛇鲻(Saurida tumbil)和六带石斑鱼(Epinephelus sexfasciatus),其IRI分别为3158.94、1755.57、1294.44和1058.46;副渔获物的幼鱼比极高。最后,作者结合相关研究,对如何从技术层面解决南海区虾拖网严重的副渔获问题进行了探讨,以促进南海区虾拖网渔业的可持续发展。 相似文献
2.
南海区虾拖网方目与菱目混合网囊渔获性能初步研究 总被引：1，自引：0，他引：1
虾拖网是南海区常见的作业方式,由于其网囊网目选择性差,虾拖网作业常产生大量的副渔获物。为了优化虾拖网网囊结构,提高其选择性,2015年8月在南海北部渔场用方形网目与菱形网目混合网囊进行试验。结果表明:虾拖网的渔获种类有34种;渔获种类中,康氏小公鱼(Anchoviella commersoni)、黑尾吻鳗(Rhynchoconger ectenurus)、中线天竺鲷(Apogon kiensis)和杂食豆齿鳗(Pisoodonophis boro)的尾数逃逸率均超过80%;周氏新对虾(Metapenaeus joyneri)和刀额新对虾(Metapenaeus affinis的尾数逃逸率最低,仅为6.18%和2.07%;周氏新对虾和刀额新对虾的50%选择体长(L50)分别为50.79 mm和53.858 mm;脊突猛虾姑(Harpiosquilla raphidea)的L50为62.51 mm;丽叶鲹(Caranx kalla)、中华青鳞鱼(Harengula nymphaea)、中线天竺鲷(Apogon kiensis)、赤鼻棱鳀(Thrissa kammalensis)和黄斑蓝子鱼(Siganus oramin)的L50分别为53.77、78.87、47.17、60.92和60.55 mm;混合网囊对鱼类副渔获的释放率较高,但对幼虾的释放率较低。建议今后放大网囊菱目段的网目尺寸进行相应的试验,提高混合网囊对目标种类的L50值,使其在释放鱼类副渔获物的同时释放幼虾,达到渔业资源的合理利用。 相似文献
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4.
80年代以来,欧美一些国家的渔业科学家开始研究海洋捕捞副渔获物(以下简称副渔获物)问题,发表了一系列文章,但对副渔获物的定义至今也没有完全统一。在我国直到目前为止,副渔获物这个名字即使在渔业界也比较陌生。1995年10月,中国水产科学研究院在江苏省南通市主持召开了“中国海洋捕捞的副渔获物(兼捕)问题和对策研究研讨会”,是我国首次副渔获物的专题会议、会后还成立了副渔 相似文献
5.
威海小石岛人工鱼礁海域渔获物群落结构特征及其与环境因子相关性 总被引：4，自引：0，他引：4
为探究人工鱼礁投放对威海小石岛附近海域渔获物种类组成、渔获量变化、渔获物结构特征的影响,作者于2012~2013年对威海小石岛人工鱼礁区及对照区的渔获物和环境因子进行了调查,并采用聚类分析、单因子相似性分析及相似性百分比分析对渔获物结构特征进行分析,采用典范对应分析(CCA)对礁区主要物种与环境因子的相关性进行分析。结果显示,南、北礁区地笼网调查到渔获物种类数量高于对照区,分别为24、31和18种。南、北礁区鱼类和甲壳类生物资源量高于对照区。南、北礁区全年资源量占优势的种类为日本蟳(Charybdis japonica)和大泷六线鱼(Hexagrammos otakii),对照区为海刺猬(Glyptocidaris crenularis)和大泷六线鱼。聚类分析和单因子相似性分析表明,渔获物组成结构在季节间差异显著(P0.05),在春季和夏季,人工鱼礁区渔获物组成结构和对照区差异显著(P0.05)。典范对应分析表明,水温、叶绿素a和溶解氧是影响礁区主要渔获物种类分布的主要环境因子。投放人工鱼礁改善了威海小石岛礁区水域的渔获物群落结构,并增加主要鱼类、甲壳类经济物种的渔获量。 相似文献
6.
黄海夏季不同取样网具渔获物组成比较分析 总被引：1，自引：1，他引：1
根据 2 0 0 0年夏季双拖渔船和“北斗”号专业调查船对应站位拖网调查资料 ,进行了两种不同取样网具情况下渔获物组成的比较分析 ,结果表明 :渔船的单位扫海面积渔获量、几种重要种类的长度范围、平均个体长度、5 0 %选择长度、重量计优势度均高于“北斗”号 ,而渔获种类数则少于“北斗”号 ,且两者种类组成相似性较低 ,仅为 0 .4 5 8;而且“北斗”号的底层、近底层鱼类和无脊椎类占总渔获量的比例高于渔船 ,这主要是由于渔具的选择作用造成的。结果说明应用渔船针对渔业生产进行的渔业资源监测 ,对带鱼、小黄鱼、鱼等重要生产种类是适合的 ,能够反映其资源量状况 ,但对群落结构、生物多样性等生态系统水平上的研究却存在着明显的不足 相似文献
7.
适用于短生命周期种类资源评估模型的研究现状与展望 总被引：1，自引：0，他引：1
《海洋湖沼通报》2015,(3)
近几十年来随着传统鱼类资源衰退,短生命周期种类的资源量和捕捞产量出现了增长,并已成为世界海洋捕捞业的重要捕捞对象,为使渔业资源可持续利用,必须制定合理的渔业管理计划,实现对渔业资源的科学管理。对渔业资源进行科学的评估是制定渔业管理计划的基础,渔业资源评估模型则是进行渔业资源评估的重要工具,对短生命周期种类资源进行科学评估和管理是一个极为重要的课题。但是短生命周期种类具有生命周期短、生长快、资源丰富以及产卵种群多的特点,资源量极易受海洋环境影响的独特的生活史特征,使得世界各国对短生命周期种类资源评估和管理的研究处在发展初期。本文首先介绍了短生命周期种类的生物学特点,接着简要介绍了传统资源评估模型的分类,最后详细阐述了目前应用于短生命周期种类的资源评估模型与方法,同时,本文对渔业资源评估模型中存在的问题进行了探讨,并对其未来的发展进行了展望。 相似文献
8.
根据2008年夏季对东山湾进行的底拖网调查资料,分析了东山湾游泳动物群落的多样性现状.结果表明,2008年夏季游泳动物调查渔获物种类共80种,以鱼类为主(54种),其余依次为蟹类(10种)、虾类(8种)、头足类(6种)和其他类(2种);渔获物优势种(IRI＞100)为红星梭子蟹(Portunus sangiunolentus)、哈氏仿对虾(Parapenaeopsis hardwickii)、白姑鱼(Pennahia argentatus)等15种;游泳动物质量相对资源密度为363.05 kg/km2,尾数相对资源密度为16 605 ind./km2,低于同季节东海大陆架和南海北部大陆架浅海海域的资源密度水平,也低于兴化湾等湾口类型海域的资源密度水平;渔获物种类和现存资源较历史数据有衰减的趋势;Shannon-Wiener物种多样性指数平均为2.08,表明该水域仅受到轻度污染,仍适合渔业资源生物的生长和繁育,但需要加强管理和养护. 相似文献
9.
为了研究桁杆虾拖网40 mm方目分离网片对渔获物的分隔效果和选择性,作者采用"套网法"于2015年8月在南海北部近海渔场进行了试验。计算分离网片对主要渔获物的尾数分隔率和质量分隔率,使用Logistic曲线作为选择性模型,运用极大似然估算法估算选择性参数。结果表明:虾拖网的目标种类为刀额新对虾(Metapenaeus ensis)和周氏新对虾(Metapenaeus joyneri),优势副渔获为丽叶鲹(Caranx(Atule)kalla);刀额新对虾和周氏新对虾的尾数分隔率和质量分隔率均大于90%;尾数分隔率和质量分隔率均大于80%的种类有:杂食豆齿鳗(Pisoodonophis boro)、黄斑蓝子鱼(Siganus oramin)、高体若鲹(Carangoides equula)和卵鳎(Solea ovata Richardson);丽叶鲹和脊突猛虾姑(Harpiosquilla raphidea)的尾数分隔率和质量分隔率均大于60%;周氏新对虾、脊突猛虾姑、丽叶鲹和黄斑蓝子鱼对分离网片的接触率分别为0.51、0.69、0.41和0.39,其50%选择体长(L50)分别为57.96±2.07、69.62±2.13、68.19±0.49和73.12 mm±1.26 mm。研究结果可为提高南海桁杆虾拖网的选择性积累数据,为缓解其对渔业资源补充群体的不良影响提供参考。 相似文献
10.
长江口区是我国最大的河口渔场,开发历史悠久,水产资源丰富。它位于东海北部，西靠大陆,有长江入海,北接吕四渔场,南邻著名的舟山渔场,东至东经124°00′,包括长江下游上海江段至佘山以东的广大水域。
长江口区的环境特点是处于沿岸水和长江冲淡水为主的低盐水系和外海高盐水系的混合区。底质以粘土质软泥、细粉砂为主。水深一般在60m以内,温、盐度变化大,以长江口引水船水文站为例,表层水温年平均为16.6℃,波动范围为5.5-27.6℃;盐度年平均为12.8,波动范围为7.19-19.9。
长江口及邻近海域水质肥沃,营养盐类和饵料生物基础丰富,是初级生产力较高的水域(刘瑞玉等,1987)。又由于水浅,地形复杂(北有长江大沙堆),造成潮流湍急,该水域成为大黄鱼、小黄鱼、带鱼和银鲳等经济种类的重要产卵场。长江口区也是夏秋季银鲳、刀鲚、凤鲚、带鱼、石首鱼类以及鲐、鲹等中、上层鱼类的重要索饵场;又是名贵种类鲥、松江鲈、中华鲟溯河或降海洄游的必经水道。河口和崇明岛近岸低盐水域还是中华绒螯蟹蟹苗和鳗苗、银鱼等的集中产区。
长江三峡工程的建造将对河口渔场及部近海域渔业资源产生什么影响,已引起人们的关注与重视。为此,进行了长江口区渔业资源调查,其目的在于了解该水域渔业资源的本底现状;并评估三峡工程建成后对渔业资源的影响,进而为持久地利用河口渔业资源提出科学依据。 相似文献
11.
《Marine Policy》2017
In this paper the discard ban policy within the Portuguese fisheries sector is discussed and the opportunities and impact in the fisheries economy that arise from sales of unwanted fish under the new landing obligation are evaluated. The decadal mean price of fish (€/kg, adjusted for inflation) rose from the 1940s until the 1970s, dropping thereafter. The yearly averaged economic income estimated for discards sales between 1969 and 2009 ranged from 419345€ to 2164379€. Discard ban sales could contribute from 10% to 53% of the total landed value and 9–34% of the total catches (landings + discards). Under a discard ban policy, the fishing sector with the largest economic contribution for total discards sales would be multispecies (54%), followed by trawl (26%) and seine (20%). On average, fishing sales contributed with 0.63% to gross domestic production (GDP) between 1938 and 2009. Discard sales can increase 1.07–1.46 times more than the fish landing contribution to GDP. After 1983 the average landings/imports economic ratio was 0.28:1, which means that fish imports surpassed landings economic value 3.57 fold. The discard ban policy can create economic opportunities in the national context thus helping to revitalize some specific fisheries sectors. 相似文献
12.
《Marine Policy》2014
In the context of the Common Fisheries Policy reform, the need for decreasing discards has been highlighted in discussions on the implementation of a discard ban. While most of the research has focused on the quantification of discards by species and métier, identification and quantification of the causes of discards have received little attention. This study presents the results of on-board surveys conducted in the Southern Bay of Biscay fleets of netters and longliners. A large variability of discards was observed. It is also shown that in these passive gear fisheries the main reasons for discarding put forward by fishermen are, firstly, market-related and, secondly, quality-related; discards related to the application of regulations are minor. The results therefore illustrate that decisions to discard can also occur in highly selective fisheries because of economic constraint and the results also show that a part is discarded alive. 相似文献
13.
《Marine Policy》2016
The landing obligation recently adopted by the European Union's (EU) Common Fisheries Policy aims to eradicate discards in EU fisheries. The objective of this paper is to investigate the potential social and economic impacts of the discard ban in European small-scale fisheries (SSF) and the critical factors for its successful implementation. An exhaustive systematic literature review and a stakeholder consultation were carried out in order to (i) collect detailed information about current knowledge on discards in EU SSF and gauge stakeholder perceptions about potential impacts of the discard ban in European SSF, (ii) examine the capacity of the SSF industry to implement the discard ban, and (iii) explore the limits and feasibility of implementing such a measure.The results of this study show that little attention has been given by the scientific community to discards in EU SSF. Indeed, the systematic literature review shows that this problem is relatively unexplored in the EU. In addition, the effectiveness of a discard ban in industrial fisheries is still unclear, mainly because discard data are not systematically collected by fisheries authorities. Stakeholders mostly perceive that the new landing obligation was developed with industrial fisheries in mind and that compliance with the landing obligation in EU SSF will be difficult to achieve without high economic costs, such as those related to the handling and storage of unwanted fish on board. 相似文献
14.
This study presents the first comprehensive estimation of discard amounts in the Galician fishing fleet, in order to provide an integral view of this increasing environmental problem at a regional scale. Subsequently, a series of improvement actions relating to discard minimization are suggested with the goal of enhancing the performance of the Galician fishing fleet through discard minimization. Discard estimates were constructed individually for the different Galician fisheries by aggregating primary data obtained from a total of 89 fishing vessels and secondary data for those fleets that were not directly sampled. Results showed that roughly 60,250 t of marine organisms were discarded by the Galician fleet in 2008, representing 16.9% of the total capture. Moreover, an important percentage of these discards were linked mainly to trawling vessels and to a lesser extent, to certain long lining fisheries. Therefore, improved management measures in target stocks should take into account the fact that alternative fishing gears other than trawl nets may reduce the amount of discards for certain species. This estimation may improve the assessment of stocks and help to quantify the damage that discards may have on wild ecosystems. 相似文献
15.
《Marine Policy》2017
Discard management needs to draw on scientific research and advice, usually supported by specific statistical modeling analysis. A wide range of statistical analysis methods were applied to fishery data in an attempt to distinguish factors that influence the species discard composition. While such approaches are important, they are still incomplete for disaggregating the economic and spatial-temporal factors for analyzing of this process and obtain a whole view of this issue. Our study aims to fill this gap by identifying, describing, and quantifying factors that influence discards of trawl fisheries using a multivariate approach based on five complementary aspects: “economic”, “vessel characteristics”, “spatial”, “temporal” and “environmental”. In addition, a spatial multi-criteria approach were used to investigate discard hot-spot areas using ecological criteria such as vulnerability and resilience of the discarded species. Using these ecological criteria will concentrate conservation efforts on the most relevant sites minimizing discards of a variety of potentially vulnerable species. This approach was applied to a case study of a multi-species demersal bottom trawl fisheries in north Spain, Cantabrian Sea (ICES area VIIIc). Results showed how spatial and economic factors highly affect species discard composition, identifying specific spatial-temporal discard hot-spots to be preferentially avoided by fishers. Mitigation measures for future fisheries management strategies should be implemented at multiple stages of the discarding process, both in the selection of the fishing grounds and the economic valorization of the discarded species. 相似文献
16.
Designing ITQ programs for commercial recreational fishing 总被引：1，自引：0，他引：1
This paper discusses the potential for implementing individual transferable quota (ITQ) schemes in commercial recreational fisheries, focusing particularly on charter and headboat fisheries. After a brief discussion of ITQs in commercial fisheries, the paper discusses the manner in which rents get dissipated in commercial recreational fisheries. Fishing mortality in recreational fisheries is determined as a joint outcome of angler behavior and trip supply. In the recreational sector under open access conditions, there are likely to be too many vessels providing too many trips at prices that are too low. Vessel input configurations are likely to be distorted in a manner that generates excessive fishing mortality. Designing ITQs for recreational fisheries requires consideration of issues not prominent in the design of commercial fisheries. Among the most important is the manner in which angler preferences and types affect overall mortality from both landings and discards. While catch and release fisheries and pure food fish recreational fisheries are relatively easy to manage with recreational ITQs, fisheries with both angler types present difficult monitoring problems that add complexities to ITQ design. Various ways to design programs that account for both landings and discard mortalities and that generate incentives for anglers and vessel owners to reduce discard mortality are discussed. 相似文献
17.
《Marine Policy》2014
The reduction of discards in European fisheries has been identified as a specific objective of the reform of the EU Common Fisheries Policy. To reduce the uncertainty in catch data and the socially unacceptable waste of resources that results from the disposal of catch at sea, a policy to ban discards has been proposed. Discard bans are currently implemented in Alaska, British Columbia, New Zealand, the Faroe Islands, Norway and Iceland. Experience from these countries highlights that a policy of mandatory landings can result in a reduction in discards, but relies upon a high level of surveillance or economic incentives to encourage fishers to land more of their catch. Discard bans will also not result in long term benefits to stocks unless total removals are reduced, through the avoidance of undersized, non-commercial or over quota catch. Experience shows that additional management measures are required to incentivise such a move towards more selective fishing. Success has resulted from the use of area closures and bycatch limits, with potential applications in EU fisheries. However, selective fishing will not be a panacea for the current state of European fisheries; discard bans and accompanying measures must be embedded in a wider management system that constrains fishing mortality to reasonable levels before sustainable exploitation can occur. 相似文献
18.
Surveys are often insufficient to accurately capture the distribution of a species in both space and time. Complementary to the use of research vessel data, platforms of opportunity can be a powerful strategy to monitor species distributions at high temporal and spatial resolution.In this study we use data from commercial fishing vessels, collecting – under the European Union data collection framework – biological data on all species that are caught and subsequently discarded. Using such discard data in combination with a systematic trawl survey, we model the spatial and temporal distribution of juvenile plaice (Pleuronectes platessa) in the central North Sea. There is a clear age-dependent difference between the commercial fishing vessel data and the research vessel data, with age 1 being the dominating age in the survey catches, while age 2 is the dominating age in the discards. The results show how immature plaice, slowly migrate from the nursery areas, westwards into the deeper regions of the North Sea. Also, the results show that during the study period, juvenile plaice gradually moved to deeper waters at an earlier age. Finally we discuss how the framework can be applied to similar opportunistic data to monitor seasonal and inter-annual migration of marine organisms, and to quantify how they may be influenced by biotic and abiotic gradients, such as temperature. 相似文献
19.
Colombia has coasts on both the Atlantic and Pacific Oceans, but its marine fisheries are limited by the relatively small size of commercially important stocks. However, diverse fishery resources have traditionally been exploited by coastal communities, and industrial fisheries have grown in recent years with the intensification of tuna fishing in both oceans. The management of Colombia's fisheries has been hampered by frequent administrative changes, which has notably led to the disappearance of a part of the official landings data. We estimated total fisheries removals (reported plus discards and unreported catches) in the Colombian Atlantic and Pacific Oceans for the period 1950–2006. We used secondary sources of information to estimate missing data, and we estimated subsistence fishing and the unreported by-catches of the shrimp and tuna fisheries. We used available information on seafood prices to estimate the relative economic impact (gross revenues) of the small-scale and industrial sectors for the period 2000–2006. Our results suggest that for the period 1950–2006, the Colombian marine fisheries catches may have been almost twice the landings reported by FAO on behalf of the country (2.8 times higher in the Atlantic; 1.3 times higher in the Pacific). Although the total gross revenues of industrial fisheries were higher than those of the small-scale sector, the latter commanded higher gross revenues in the Atlantic in 2006. 相似文献
20.
《Marine Policy》2013
Bycatch presents a challenge to optimizing yield in commercial fisheries, where bycatch can total more than 1 million mt per year in the United States. Yet the economic impacts of bycatch have rarely been evaluated in the scientific literature. These economic impacts largely occur from the loss of landings through (1) early closure of fisheries when catch limits of bycatch species are reached; and (2) discards of marketable catch due to regulatory requirements in the fishery. This paper illustrates the economic impacts of early closures due to bycatch in U.S. fisheries by describing past case studies, as well as evaluating the economic impacts of discarding fish in U.S. commercial fisheries. Premature closures in the fisheries reviewed resulted in potential losses ranging from $34.4 million to $453.0 million annually. Nationally, bycatch estimates in the form of regulatory discards are annually reducing the potential yield of fisheries by $427.0 million in ex-vessel revenues, and as much as $4.2 billion in seafood-related sales, $1.5 billion in income, and 64,000 jobs. Our review also shows that some of the most promising work to reduce bycatch over the last decade has been the development of gears or gear modifications, termed “conservation engineering.” 相似文献