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1.
Strategic long‐term sampling programmes that deliver recreational catch, effort and species demographic data are required for the effective assessment and management of recreational fisheries and harvested organisms. This study used a spatially and temporally stratified observer programme to examine variation in the rates, quantities and lengths of retained and discarded catches of key species in a recreational charter fishery. Geographic region, but not season, significantly influenced catch rates of key demersal species, being driven by temporally persistent latitudinal clines in environmental conditions influencing species distributions. There was considerable trip‐to‐trip variation in catch rates that were attributed to localised differences in fishing operations, locations, environmental conditions and client preferences. Broad trends in retained and discarded catch rates were nevertheless, similar across different fishing effort standardisations (per‐trip, per‐hour, per‐client, per‐client/fished hour), demonstrating that the coarsest unit of effort could be used in fishery assessments. Discard rates of organisms were variable and driven by a combination of mandated legal lengths, individual client and operator preferences for particular species and sizes of organisms, and not due to attainment of catch quotas or high‐grading. This study has identified important fishery attributes that require consideration in assessing charter fisheries and stocks of recreational fish species. 相似文献
2.
Laurne A. Lecaudey Martin Schletterer Vyacheslav V. Kuzovlev Christoph Hahn Steven J. Weiss 《水产资源保护:海洋与淡水生态系统》2019,29(10):1785-1800
- The headwaters of the Volga River exhibit large reaches with near‐pristine conditions, and therefore long‐term biodiversity monitoring of this catchment can provide rare and valuable information on a European lowland river. More specifically, freshwater fish species assemblages are a good indicator of ecosystem status, as they are particularly sensitive to environmental changes and hydromorphological alterations. Historical records show that the fish fauna of the Upper Volga has changed over time, both in species composition and in abundance. The construction of the Volga–Kama cascade (a series of large dams) has specifically affected the migration of diadromous species.
- Environmental DNA metabarcoding offers a non‐invasive approach to determine the number of species in an aquatic ecosystem, as well as their identity and distribution. This approach is especially useful for fish fauna surveys along large rivers and long‐term biomonitoring, with the advantage of having no impact on the species and their habitats.
- To infer the current fish species diversity and the spatial distribution of each species in the free‐flowing section of the Upper Volga River, as well as in selected tributaries, an environmental DNA metabarcoding approach was applied, using three mitochondrial DNA markers. This method allowed the positive identification of 23 fish species and their respective distributions in the headwaters of the Volga.
- This assessment provides a valuable example of the application of environmental DNA metabarcoding in a large river system, and constitutes a starting point for future investigations and long‐term biomonitoring in the Upper Volga system. In addition, the results can also serve as a reference for fish diversity assessments of other large European lowland rivers, and can guide future conservation and management measures in the headwaters of the Volga.
3.
嫩江流域的各大湖泊,由于盐碱性强,导致鱼类种类少,产量低。通过引嫩工程,使各大盐碱湖泊水质得到了改善,改水洗碱,使湖水盐碱率下降,形成了良好的渔业生态环境。旨在通过此种养殖实践,让更多的盐碱湖泊得到开发利用。形成与环境保护相协调的渔业产业发展格局。 相似文献
4.
为了准确评价海洋生物多样性状况,研究较长时间内社会经济发展对生物多样性的影响,收集和监测2003-2013年山东省长岛县社会经济、生态环境和环境保护等数据,以压力-状态-响应(PSR)框架模型为研究方法,结合长岛县社会经济和生态环境特征,筛选出14项指标组成长岛县海洋生物多样性评价指标体系,综合分析相关国家及行业标准、统计年鉴和长岛县各相关指标历史监测数据,确定各评价指标的基准值,运用层次分析法确定各指标的权重,根据建立的海洋生物多样性进行体系评价。结果表明,长岛县海洋生物多样性状况较好,海洋生物多样性指数(MBDI)最大值为2006年(0.766),最小值在2012年(0.600),评价等级均为良;生物多样性所受压力较小,生物物种较丰富,局部地区生物种类高度丰富,生态系统功能较为完善,受到干扰后一般可以恢复,生境质量一般适宜生物生存。分析其压力、状态和响应指标的变化,水质和保护生物组成的状态指标非常稳定;压力指标有一定程度的上下起伏,2008-2011年呈较明显的下降趋势;响应指标值2003-2013年基本稳定并略呈上升的趋势。从总体上看,长岛县海洋生物多样性状态优良且基本稳定。 相似文献
5.
- 1. The Water Framework Directive (WFD) requires member states to establish ‘type‐specific biological reference conditions’ for the assessment of surface waters and describes a method for establishing such biological targets. The methodology described in the Directive is based on geographic and physical characteristics and similar to the ‘multimetric’ approach used widely in North America, but contrasts with the biological classification of the ‘multivariate’ approach which is commonly used in Europe.
- 2. An investigation was made of the relative efficiency of the multimetric and multivariate classification approaches in partitioning the observed biological variation of the macroinvertebrate communities of 22 minimally disturbed lakes in Northern Ireland. Furthermore, the accuracy of predictive models based on the two approaches was compared.
- 3. The WFD environmental typologies partitioned the observed biological variation poorly with a maximum ANOSIM R‐value of 0.216 compared with 0.609 for a multivariate biological site classification. The WFD System B approach partitioned more variation than the System A approach.
- 4. The use of a predictive model, based on any of the site classification approaches, resulted in more accurate faunal predictions than a null model. However, the biological model produced the most accurate predictions.
- 5. Canonical correspondence analysis showed that the environmental variables used in the biological classification model explained more variation (28%) than the best‐performing environmental classification model (24%). The most important variable was pH, followed by surface area and altitude. The variables used in all approaches explained more variation when used as continuous rather than categorized parameters.
- 6. The results of this work, the first such comparative study of predictive models in lakes, concur with similar studies in streams. It may be concluded that large‐scale environmental classifications are unreliable as a method for setting type‐specific reference targets for the ecological assessment of fresh waters.
6.
- Species are disappearing at a rate comparable with previous mass extinctions. Freshwater environments are being particularly affected, with biodiversity losses occurring much faster in freshwater than in terrestrial or marine ecosystems.
- This study assessed the research on drivers of biodiversity loss in freshwater environments as described in nearly 37,000 articles published in the last decade. Articles on biodiversity published between 2010 and 2019 were retrieved from the Web of Science to determine the number of articles that addressed a particular driver of biodiversity loss, by analysing the titles, abstracts, and keywords. The biodiversity and development status of a country was also investigated to see how it affects its scientific output (i.e. number of published articles).
- Twenty per cent of the articles on biodiversity addressed freshwater biodiversity. Researchers devoted considerable effort to six drivers – climate change, water pollution, flow modification, expanding hydropower, species invasions, and habitat degradation – but practically ignored other threats, such as plastic and light pollution. It was also found that megadiverse countries, which for the most part were also developing countries, published substantially fewer articles than developed but less biodiverse countries.
- We recommend a series of actions that could contribute to mitigate the biases found in this study.
7.
- 1. Historically, ecological assessment of lakes has depended on open‐water chemical and phytoplankton analysis, with trophic status determined by chlorophyll a and total phosphorus following the general protocol of the OECD lake classification scheme. This has been accompanied by a prevailing opinion that the littoral zone of lakes is too heterogeneous to allow meaningful inter‐lake comparisons.
- 2. Council of the European Communities Directive 2000/60/EC establishing a framework in the field of water policy (the Water Framework Directive) requires a broader approach to ecological assessment, including the need to incorporate a range of biotic variables. This paper describes the results of a monitoring programme designed to determine within‐ and among‐lake variation of macroinvertebrate communities found in defined mesohabitats of 22 lakes incorporating a range of lake types. Three sampling approaches were applied to the study.
- 3. Triplicate macroinvertebrate samples from a cobble/pebble mesohabitat of 11 lakes showed that community composition from a standard habitat was robust.
- 4. Twinned samples from contrasting habitats of pebble/cobble and macrophyte dominated mesohabitats of 21 lakes had greater similarity within than among lakes. This showed that even across contrasting habitat structure, macroinvertebrate assemblages can provide a reliable lake‐specific indicator.
- 5. Multivariate analysis of replicate samples from 15 visually distinct mesohabitats in one lake showed that within‐lake variation could, nevertheless, be identified as distinct clusters of invertebrate assemblages.
- 6. Conclusions from the work are that variations within lakes were nested in among‐lake variation across a range of lake types, and that macroinvertebrate assemblages can provide meaningful assessment of ecological differences across lakes. Monitoring can, however, produce a substantial amount of ‘noise’ from the data that reflects the complexity of macroinvertebrate community structure in littoral zones. It is recommended that incorporation of macroinvertebrates in ecological assessment is most useful when confined to well defined mesohabitats rather than attempt to incorporate a complete range of mesohabitats within a single lake.
8.
As an alternative food source to wild fisheries, aquaculture shows a great potential to help meet the growing demand for seafood and animal protein. The expansion of aquaculture has been achieved partly by system intensification, which has drawn vast criticisms of aquaculture for its environmental, social and economic sustainability issues. Life cycle assessment (LCA) has become the leading tool for identifying key environmental impacts of seafood production systems. A LCA evaluates the sustainability of diverse aquaculture systems quantitatively from a cradle‐to‐grave perspective. It provides a scientific basis for analysing system improvement and the development of certification and eco‐labelling criteria. Current efforts focus on integrating local ecological and socio‐economic impacts into the LCA framework. A LCA can play an important role in informing decision makers in order to achieve more sustainable seafood production and consumption. This article reviews recent applications of LCA in aquaculture, compares the environmental performance of different aquaculture production systems, explores the potential of including biodiversity issues into LCA analysis and examines the potential of LCA in setting criteria for certification and eco‐labelling. 相似文献
9.
研究河口潮间带底栖生境(intertidal benthic habitat)变化,能为河口湿地生物的保护、底栖环境质量的评价、受损生境的生态恢复提供的科学依据和管理建议。本文从关注空间和时间尺度的研究出发,对河口潮间带栖息地监测、分类与评价方面的研究进展进行了归纳总结,分为以下六个方面进行论述:河口潮间带底栖生境的时空新特征、河口潮间带底栖生境特征参数、河口潮间带底栖生境特征获取方式、数据处理、河口潮间带底栖生境分类模型选择、多时空尺度分析。河口潮间带底栖生境特征的分类方式由于考虑生态过程和格局中所涉及的空间生态学问题(边界分割、尺度效应、分类精度、动态变化等),模拟底栖物种及群落分布更为便捷,最终使物种/群落栖息地分类结果更加精确、真实、全面。最后,本文提出利用SIT对河口潮间带底栖生境进行分类将对底栖生态系统评价及研究生态功能机制带来新的视角,同时也需注意一些问题。例如,潮间带生境特征参数需要选择合适的统计方法在不同的尺度上进行甄别和筛选,以期有效提高指示参数在研究尺度上的解释度。 相似文献
10.
Robyn E. Jones Richard K.F. Unsworth Jon Hawes Ross A. Griffin 《水产资源保护:海洋与淡水生态系统》2021,31(6):1379-1391
- Biodiversity in turbid aquatic environments is commonly assessed using extractive sampling methods that damage the seabed. Underwater cameras equipped with clear liquid optical chambers (CLOCs) for the assessment of seabed habitats and species are a non-extractive alternative and have been applied in turbid environments globally. A CLOC is a body of clear liquid positioned in front of a camera to reduce the scattering of light that would otherwise occur when passing through the turbid water it displaces. Here, we test and quantify the effectiveness of a CLOC for marine benthic biodiversity assessments over gradients of increasing turbidity.
- The addition of a CLOC to a conventional benthic camera system significantly enhanced the quality of information gathered. Images acquired using the CLOC system consistently recorded statistically higher values of image quality (49% increase, based on the clarity of the image), seabed visible within the drop-down frame (34% increase), and European Nature Information System habitat level identification (49% increase). Furthermore, it was found that the ‘annotation success’ of taxa (classification of a specimen to family level or higher) was found to increase between individual experts in the presence of a CLOC. A reduced sampling effort was also identified when using a CLOC. Taxonomic richness increased by 27% when comparing the same number of image stills collected with and without the CLOC.
- By reducing the limitations of underwater visibility previously attributed to underwater cameras, this concept extends the potential for use of non-destructive survey techniques and allows for future users to collect robust information of an area, making better informed management decisions.
11.
Nicholas R. Perkins Geoffrey R. Hosack Scott D. Foster Nicole A. Hill Neville S. Barrett 《水产资源保护:海洋与淡水生态系统》2019,29(1):59-71
- Monitoring the impacts of pressures, such as climate change, on marine benthic ecosystems is of high conservation priority. Novel imaging technologies, such as autonomous underwater vehicles (AUVs), remotely operated vehicles (ROVs), and towed systems, now give researchers the ability to monitor benthic ecosystems over large spatial and temporal scales.
- The design of monitoring programmes that use such technologies is currently hindered by a lack of information about the typical abundance and spatial distributions of target indicators and the level of sampling required to detect changes. A further complicating factor is that these sampling platforms are often not able to be exactly relocated when conducting repeat surveys.
- How the spatial properties of benthic organisms influence the estimates of cover, given alternative designs that vary in the geolocation precision of transects and the sampling intensity of images, is explored. A geostatistical modelling approach is used to quantify the spatial distribution of 20 key deep‐water invertebrate species at a long‐term monitoring site. The parameter estimates from these models are then used to simulate repeat transects with geolocation error and different levels of sampling.
- Results suggest that species with short effective ranges (i.e. those with strong spatial dependence over relatively short distances) and large spatial variance, which suggests strong spatial dependence effects, will require greater sampling effort to achieve a given standard of precision.
- Spatial offsets of 2 m, typical of an AUV, are unlikely to have dramatic impacts on the precision of estimates when sufficient images are sampled, but offsets of 10 m that are typical of towed systems may require a prohibitively high sampling effort for some species. These findings have important implications for benthic monitoring programmes, and highlight the importance of considering the interactions between sampling design, the technical limitations of survey equipment, and the spatial properties of indicator species.
12.
M. Fernanda Alvarez;Lía C. Solari;Gabriela C. Küppers;Néstor A. Gabellone;Hernán H. Benítez;Matilde Vojkovic;M. Cristina Claps; 《水产资源保护:海洋与淡水生态系统》2024,34(12):e70019
Freshwater biodiversity is declining sharply. The conservation of these biodiverse habitats has generally depended on their designation as protected areas, but specific groups such as plankton tend to be overlooked. The Salado River (Argentina) constitutes a highly characteristic morphologic feature of the pampas, having a basin of 150,000 km2. The Las Flores system, particularly, is key in the development of the river, and the presence of two tributaries adds landscape heterogeneity with habitats such as shallow lakes, backwater ponds and wetlands. Our aim in this work was thus to evaluate the Salado River conservation status by measuring the specific richness of its planktonic community in order to argue for the Salado's establishment as a protected reserve. An analysis of the phytoplankton and zooplankton assemblages after several years of sampling in the river, streams and backwater ponds indicated that habitat heterogeneity increased the diversity of the region and that sites such as backwater ponds or streams were critical for the functioning of the river system as a whole through adding particular species or acting as species reservoirs. This supports habitat fragmentation in the area, which combined with environmental heterogeneity contributed to high ß diversity values. However, such separation also involves a trade-off because prolonged isolation between subsystems can result in net species loss. Finally, the present work focused on the significance of biodiversity at the landscape level, with planktons as a model for the conservation of a principal site in one of the main rivers of Argentina. 相似文献
13.
于2005-2007年夏季采集闽东沿岸生态监控区68个经济水产品样品,用气相色谱法测定其中的六六六(BHCs)、滴滴涕(DDTs)的残留量,并对其残留水平、分布趋势和组成特征,以及污染现状、食用安全和人体健康风险进行探讨与评价。结果表明:贝类、虾类、蟹类和鱼类的BHCs的残留范围分别为未检出~1.53 μg/kg、未检出~0.830 μg/kg、未检出~1.21 μg/kg、未检出~4.02 μg/kg(湿重),DDTs的残留范围分别为0.184~66.9 μg/kg、未检出~2.87 μg/kg、8.04~126 μg/kg、0.891~310 μg/kg(湿重)。BHCs污染指数均小于0.5,未受到BHCs的污染;71.2%的样品DDTs的污染指数在0.581~31.0之间,不同程度受到DDTs的污染。与国内外其它海域相比,闽东沿岸生态监控区经济水产品中BHCs残留量处于较低水平,而DDTs残留量处于国内邻近海域中等水平、亚太等国外海域较高水平。贝类和鱼类的p,p′-DDT的含量较高,p,p′-DDT/DDTs平均含量比分别为43.8%和49.1%,推测有新的DDTs类污染物输入。闽东沿岸生态监控区经济水产品中BHCs、DDTs的残留量符合我国的无公害水产品质量安全标准,低于欧盟、美国、日本的食品安全限量;参照美国环保局(US EPA,2000)推荐的危害参考剂量RfD和可疑化学物质致癌斜率因子的接触风险指数ERI和致癌风险指数CRI分析表明,闽东沿岸生态监控区经济水产品消费引起的BHCs、DDTs的接触风险和潜在致癌风险均为可接受风险。 相似文献
14.
评价水环境治理工程对流域水生态环境的影响,可为茅洲河流域进一步的生态修复工作提出建议。对水环境治理初期(2016年5月)和治理期间(2018年8月)茅洲河流域水生态状况进行调查,选取44个采样点,覆盖茅洲河流域的干流以及主要支流,以获取的样本和水质理化数据,对比分析水质、底栖动物群落、浮游藻类及大型水生植物群落变化。结果显示,治理期间茅洲河流域水体化学需氧量(COD)、氨氮(NH_3-N)和总磷(TP)平均浓度分别降低了41.2%、50.6%和66.7%,溶解氧(DO)平均浓度升高了130.8%;底栖动物群落物种多样性增加了53.6%,耐污种类的密度和优势度降低,并在部分样点新增敏感性较高的蜉蝣目、鞘翅目、毛翅目和半翅目水生昆虫类群。大型水生植物种类和分布范围明显增加,流域内分布有挺水植物24种、沉水植物4种、漂浮植物2种、浮叶植物1种。Palmer藻类污染指数指示为重污染的样点减少了56.3%,中污染样点增加了16.3%,轻污染的样点增加了40.0%。BMWP指数评价结果也有好转,最高得分为49。研究表明,治理后的茅洲河流域水污染程度降低,生态环境状况总体有所好转,但流域生态健康状况仍然较差,需进一步开展系统的流域生态修复工作。 相似文献
15.
Lin Cheng Simon Blanchet Géraldine Loot Sebastien Villéger Tanglin Zhang Sovan Lek Sithan Lek‐Ang Zhongjie Li 《水产资源保护:海洋与淡水生态系统》2014,24(1):23-34
- Habitat modification by humans has severe impacts on the biotic and abiotic components of freshwater ecosystems. In China, shallow lakes in the Yangtze River basin are facing major habitat modification owing to the loss of their natural connections with rivers and the development of aquaculture.
- In this study, temporal data (ranging from 1970 to 2010) from a set of lakes (n = 8) were used to quantify the abiotic and biotic consequences (i.e. taxonomic and functional diversity of fish communities) of such human activities. There were significant abiotic changes that mainly occurred after the 1990s. Specifically, water transparency decreased and the total nitrogen content of the lakes increased considerably.
- A trend (although not significant) was detected towards a decrease in fish species richness over the period studied. The taxonomic dissimilarity (i.e. beta‐diversity) among fish communities decreased significantly over the years, indicating a strong homogenization of the fauna across the lakes.
- In addition, it was found that fish functional diversity has decreased in most lakes since the 1970s. In particular most migratory fish species with long life‐spans and large body size disappeared from the lakes, hence contributing substantially to the observed decrease in functional diversity.
- Based on the findings, it is argued that both the abiotic and biotic integrity of the lakes were seriously affected after the lakes lost their connections to the rivers. It would therefore be helpful to reconnect the lakes to rivers with wise sluice‐gate management, and regulate fishery activities in those lakes to restore fish diversity.
16.
Sebastian Theis Lyndsay Cartwright Andrea Chreston Brynn Coey Brian Graham Don Little Mark Poesch Rick Portiss Ryan Scott Angela Wallace Jonathan L. W. Ruppert 《水产资源保护:海洋与淡水生态系统》2024,34(4):e4141
- Biodiversity and habitat loss due to historical and continued urbanization and anthropogenic development require continuous efforts to abate ongoing environmental decline. Restoration and enhancement efforts that aim to address biodiversity and habitat loss, have shown some promise at providing suitable habitat for species in the more urbanized nearshore areas of Lake Ontario.
- Using 20 years of fish community data from the Toronto waterfront, this study examined ecosystem responses in a spatio-temporal context across wetland and embayment ecotypes. The goals of this study were to (1) assess how fish communities have changed over time in restored, reference and more and less urbanized nearshore ecosystems and (2) determine if restored and enhanced habitats meet the defined fish community management targets.
- Fish communities were assessed through a newly developed multi-metric index based on species life history traits and habitat associations like trophic and thermal guild.
- Fish communities along the waterfront have transitioned from cool and coldwater pelagic species to a higher proportion of native warmwater species, many of them piscivores, associated with cover and vegetation, that meet community targets. These changes are more pronounced at the largest restoration site ‘Tommy Thompson Park’, where community indices approach natural reference levels. This result indicates the benefits and effectiveness of the decade-long restoration efforts and subsequent monitoring of responses. Our results underline that large-scale restoration projects in urbanized settings can be of vital importance for freshwater conservation efforts, as well as application scenarios for multi-metric community indices, and will play an even larger role when looking at Lake Ontario or the Great Lakes as a whole.
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根据2008年5月至2009年2月对流沙湾贝类养殖海域渔业环境综合调查的数据,对海水环境质量的现状进行了分析讨论,综合评价了海水有机污染和营养水平,并对沉积物重金属的累积程度和潜在生态危害进行了评价。结果表明,调查海域盐度、溶解氧（DO）、化学耗氧量（COD）、无机氮（DIN）和活性磷酸盐（PO4^3-）呈季节性变化,其中盐度和DIN的季节变化与该海域季节性降水有关,而DO、COD和PO4^3-的变化与浮游植物和贝类养殖有关。评价结果显示,流沙湾海域水质清洁,海水氮（N）营养盐过剩而磷（P）贫乏,属于P限制型中等富营养化海域;调查海域沉积物中砷（As）和铅（Pb）处于无污染状态,汞（Hg）和镉（Cd）处于轻度污染,铜（cu）在部分区域处于中度污染状态;Ca、Pb、As、锌（Zn）和铬（Cr）的潜在生态危害属于轻微,Hg和Cd的潜在生态危害处于中等强度。 相似文献
19.
在天津海域的北塘河口,用浮游生物网和球阀采水器采集了浮游植物和浮游动物样品,分析2种采样方法对生物多样性指数的影响。结果表明,北塘河口共检测出浮游植物34种,硅藻占绝对优势;浮游动物17种,桡足类占据优势地位。生物多样性指数和丰度值因采样方法而异。用浮游生物网采集浮游植物样品时,能够获得较多的种类数和较高的Margalef指数、Pielou均匀度指数、Shannon指数和Simpson指数;而优势度指数和分类学差异性指数的结果则较低;用采水器采集的浮游动物样品具有较高的Shannon指数、Pielou均匀度指数、Simpson指数和分类学多样性(Δ);其他指数的结果则相反。网采样品具有较低的生物丰度值。t检验结果显示,种类数和Margalef指数受取样技术的影响显著;而其他几个指数的差异不显著;由于很多指数是按照阈值来评价环境优劣,数值不同依然可能影响评价结果;因而在比较不同研究结果和评价环境时应该注意取样方法的影响。 相似文献
20.
Catch‐per‐unit‐effort is often used as an approximation of population size. However, for the management and conservation of populations, information about the number of individuals is fundamental. Pike, Esox lucius L., is a popular fish species for recreational anglers. In this study, data in the form of journal keeping by anglers were used: date; place; and photographs of the captured fish; pike were identified based on their natural markings in combination with length measurements. The data were analysed by spatial capture–recapture (SCR) models. Results showed that a small and densely vegetated lake (6.7 ha) in south‐eastern Sweden had a population size of 91 (±22 SE) pike ≥60 cm. On one occasion, 10 individuals were caught, that is 11.1% of the population, highlighting that angling may potentially have a substantial impact on the population size. Hopefully, this study can inspire angler–manager collaborations for conservation of fish stocks. 相似文献