斑点叉尾鮰养殖池塘底泥微生物群落结构特征及其影响因素

微生物群落在水产养殖环境中起着重要作用,深入了解微生物群落组成及其构建机制对了解池塘生态功能具有重要意义。本研究通过高通量测序技术研究斑点叉尾鮰（）养殖池塘底泥中细菌群落机构特征,并分析了细菌群落的主要影响因素。结果显示,斑点叉尾鮰养殖池塘底泥细菌群落结构呈现出季节性变化,冬春季样品相似性较高。斑点叉尾鮰养殖池塘底泥优势菌群主要为变形菌门（Proteobacteria）、绿弯菌门（Chloroflexi）、拟杆菌门（Bacteroidetes）、厚壁菌门（Firmicutes）和酸杆菌门（Acidobacteria）,与池塘水体细菌群落间有明显的差别。线性判别分析显示,冬、春和秋季的特异性优势菌群较为丰富,冬季和春季分布较为集中,分别集中于浮霉菌、拟杆菌门、绿弯菌门和厚壁菌门、拟杆菌门,秋季特异性优势菌群分布特别分散,而夏季优势细菌类群最少,只有绿弯菌门厌氧绳菌属1个属具有显著优势。环境因子中,透明度和总溶解性悬浮物与斑点叉尾鮰养殖池塘底泥细菌群落结构有显著相关（<0.05）,对细菌群落结构的影响也最大。本研究旨为斑点叉尾鮰池塘微生物群落的变化和调控提供借鉴。     

Wintering seaducks in Britian and Ireland: Populations,threats, conservation and research priorities

• 1. This paper provides a detailed review of the status and distribution of wintering seaducks (Scaup, Eider, Long-tailed Duck, Common Scoter, Velvet Scoter and Red-breasted Merganser) in Britain and Ireland. It is based on a literature review plus analysis of National Waterfowl Counts (NWC) and other data. A summary of current knowledge of wintering seaducks is provided together with information on threats to populations, conservation goals and research needs.
• 2. Each species is examined in turn, with the emphasis on aspects of the population, habitat use, current distribution, trends and history. Important areas for individual species are highlighted.
• 3. Overall, seaduck populations have changed considerably, those for Eider and Red-breasted Merganser having expanded greatly, whilst those for Scaup, Common and Velvet Scoter have declined during historical and/or recent times. The trend for Long-tailed Ducks is unclear. British population estimates are considered to be out of date and need to be revised. The premier areas for seaduck communities are highlighted, thus providing basic information for conservation action and future monitoring.
• 4. Seaduck populations are threatened in a number of ways and the main factors are discussed. Oil pollution and the actions of commercial fisheries are the most important current threats. Conservation goals are suggested. These include an urgent need to develop appropriate domestic legislation to facilitate the protection of seaduck populations. Such legislation is currently almost entirely lacking.
• 5. Some priorities for research, particularly for better population monitoring of seaducks in British and Irish waters, are provided. These include: alterations to the NWC scheme to allow the collation of opportunistic counts, made when the conditions are amenable for censusing seaducks; extension of the scheme into areas not currently surveyed (e.g. most parts of Ireland); and the establishment of intensive survey programmes to monitor seaducks in the key areas of Britain and Ireland. It is hoped that this paper will serve to stimulate interest and commitment from all who play a part in safeguarding our seaduck heritage.

     

Ecology,habitat and bird community structure at Oussudu lake: towards a strategy for conservation and management

• 1. Oussudu lake is a large, shallow wetland situated close to the city of Pondicherry, India. The lake harbours rich flora and fauna, and has been recognized as one of the important wetlands of Asia by the International Union for Conservation of Nature and Natural Resources (IUCN).
• 2. This paper summarizes the results of a 5‐year study on the annual composition, richness, diversity and population density of the bird community at Oussudu. A GIS database was developed on the basis of field surveys and allied studies.
• 3. The study reveals a declining trend in the number and diversity of the birds found at Oussudu with the exception of herons, egrets, plovers and lapwings. A relationship appears to exist between this decline in bird diversity and an increase in illegal fishing, cattle grazing, encroachments and pollution. These factors may have contributed to the decline of food and shelter for the birds.
• 4. A strategy has been developed for the conservation and management of the Oussudu catchment which would help in reversing undesirable trends.

Copyright © 2003 John Wiley & Sons, Ltd.     

The identification,characterization and conservation value of isoetid lakes in Ireland

• 1. Soft‐water, oligotrophic isoetid lakes are vulnerable to eutrophication, acidification and alkalinization. As a result of these pressures a large proportion have undergone substantial deterioration in several European countries. The understanding of these systems has been limited by either a lack of lakes close to natural conditions or through receiving less focus in broader scale macrophyte surveys. This has resulted in a dearth of information on specific lake types in their natural condition. Sixty‐eight soft‐water lakes in Ireland were studied in order to achieve a better understanding of the biological and environmental conditions defining such lakes.
• 2. Eight groups of lakes were identified using cluster analysis and indicator species analysis. Three groups were representative of isoetid‐rich lakes displaying a high frequency of occurrence of Isoetes lacustris, Lobelia dortmanna or Eriocaulon aquaticum together with the almost ubiquitous Littorella uniflora. Canonical variates analysis indicated that alkalinity, total phosphorus (TP), catchment area, altitude, moors and heathlands, mean transect depth, colour and lake area were significant variables discriminating among the eight groups. Soft‐water lakes with high amounts of isoetids tended to be less exposed, have broad shallow littoral zones with a high transparency and be situated in smaller catchments. Total phosphorus and alkalinity were typically low, although one group of isoetid‐rich lakes had higher mean TP and alkalinity values. This group may contain lakes under threat from nutrient enrichment and alkalinization and also lakes that have higher TP and alkalinity naturally.
• 3. Lakes with a prevalence of isoetids supported a greater diversity of macrophytes and chironomids indicating that such lakes may represent suitable conservation targets as they act as surrogates for soft‐water lakes of high biodiversity. Other factors favouring a focus on isoetids in conservation strategies are their importance as a functional component in soft‐water lakes and their sensitivity to lake and catchment environmental change.

Copyright © 2008 John Wiley & Sons, Ltd.     

Native and introduced fish community structure in a freshwater swamp forest: Implications for conservation and management

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The eel fishery in Lough Neagh,Northern Ireland – an example of sustainable management?

Abstract  Lough Neagh produces over 500 t of grown eel annually and employs 300 people fishing yellow and silver eel. Glass eel are transported upstream and stocked into the Lough. Since glass eel returns crashed in the 1980s, additional glass eel seed has been purchased from other fisheries. The fishery now faces ecological, social and economic pressures. Prices for the product have fallen; recruitment to the fishery has declined, and seed has decreased in availability and increased in price. Fishers are less inclined to take up the hard work required to make a living fishing eel and the fisher population is ageing. The European Commission has recognised the decline of eel and proposed emergency measures, which may further affect the viability of the fishery. The sustainability of the fishery is examined, based on the relationship between glass eel input and grown eel outputs over a period of 45 years, set against increasing environmental, socio-economic, and natural resource pressures. Spawning escapement of silver eel is estimated by mark–recapture experiments.     

福建东吾洋海域海水和沉积物菌群结构及其与环境因子相关性

福建东吾洋海域是我国刺参(Apostichopus japonicus)吊笼养殖的核心产区,但目前该地区的水域环境现状和环境菌群结构相关研究匮乏。本研究以东吾洋海域东安、马坑、雷江和沙湾4个主要养殖区域为对象,完成了海参养殖高峰期1月的水质环境因子调查和评价分析,采用高通量测序方法完成了水体和沉积物菌群多样性和差异特征菌群分析,解析了环境因子与菌群结构相关性。结果表明,马坑海域的富营养化指数为21.60,属于严重富营养化;东安和雷江海域属于重度富营养,只有沙湾海域处于中度富营养的水平。东安和沙湾海域水质属于轻度有机污染,而马坑和雷江海域属于中度有机污染。高通量测序共获得1 520个操作分类单元(operational taxonomic units, OTUs),归属于28门、57纲、163目、322科、581属。菌群结构多样性分析表明,各区域沉积物的菌群多样性水平均显著高于相应海域水体菌群多样性,且具有较强的空间异质性。沙湾海域环境菌群多样性与丰度最高。PCo A分析表明,沉积物和水体中细菌群落结构差异极显著,水体交换和海域位置对其水体和沉积物菌群结构的影响较大。具有潜在致病性的弧菌...     

Predicting catches for the Lough Neagh (Northern Ireland) eel fishery based on stock inputs, effort and environmental variables

Abstract  The Lough Neagh eel fishery is the largest remaining commercial source of wild European eels. Following the pan-European elver crash in the 1980s, the numbers of elvers entering the Lough fell drastically, prompting the Lough Neagh Fishermen's Co-operative Society Ltd (LNFCS) to purchase additional glass eels from a UK distributor. LNFCS have continued to purchase glass eels, when market prices have been favourable, to supplement the natural glass eel input. This study assesses the impact of these stocked glass eels on the Lough Neagh yellow and silver eel fisheries with a predictive model based on natural and stocked glass eel input, effort and environmental variables. Despite the final models' limitations to assess conclusively the contribution of the additional purchased glass eels the models can be used cautiously to predict, in the short term, yellow and silver eel output. The models will require reviewing, on an annual basis, as further data become available.     

A comparison of environmental and biological site classifications for the prediction of macroinvertebrate communities of lakes in Northern Ireland

• 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.

Copyright © 2007 John Wiley & Sons, Ltd.     

Science,capacity building and conservation knowledge: The empowerment of the local community for marine conservation in Rapa Nui

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Fish conservation in freshwater and marine realms: status,threats and management

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崂山近岸浮游植物群落结构季节变化及其环境影响因素

为了解山东省青岛市崂山近岸海域浮游植物群落结构变化特征及其与环境因子的关系,于2016~2017年的春、夏、秋3个季节在该海域设置15个监测站位进行调查,并同步监测海区环境因子。结果显示,共检出浮游植物2门31属69种。其中,硅藻门(Bacillariophyta)为绝对优势门类,共25属60种,甲藻门(Pyrrophyta)有6属9种。调查海区浮游植物细胞丰度变化范围为(732.10~ 1142.19)×104 cell/m3,平均为937.15×104 cell/m3。浮游植物细胞丰度季节变化明显,2016年最高峰出现在秋季;2017年最高峰出现在夏季;空间分布上,春、夏2个季节呈现由北向南递减的趋势。浮游植物群落结构特征指数分析结果显示,调查海域浮游植物的多样性指数和丰富度指数均较好,表明该海域浮游植物群落结构比较稳定。聚类分析结果显示,春季浮游植物细胞丰度季节变化不大,2016和2017年相似性高达70%左右,但夏、秋季的浮游植物细胞丰度季节变化较大,相似性仅为40%左右,这主要与环境因子变化有关。浮游植物群落结构与环境因子相关性分析表明,浮游植物细胞丰度平均值与化学需氧量(COD)的相关系数最高,最高值为0.536,其次与之相关的双因子组为pH与COD、COD与无机氮(DIN)、溶解氧(DO)与COD。因此,崂山近岸海区浮游植物细胞丰度的关键限制因子为COD、pH、DIN和DO。     

Recovery,conservation status,and environmental effects on arapaima populations in Guyana

1. Using population estimates that were made regularly between 2001 and 2013, the state of recovery of arapaima populations and their IUCN conservation status were assessed after they were almost extirpated from the upper Essequibo basin, Guyana. Recovery rates were compared across multiple areas with different degrees of access by fishers to evaluate effectiveness of conservation efforts.
2. Population estimates were also used to investigate the influence of environmental factors on arapaima abundance in lakes with different morphometries, vegetation, and water types and to determine the relationship between the numbers of spawning individuals and subsequent recruits (at about age 2 years).
3. The most recent census conducted in November–December of 2013 indicated a 5.6-fold increase in overall abundance compared with 2001, with 4,591 individuals, of which 1,932 were juveniles (1.0–1.5 m total length) and 2,659 adults.
4. Assessment of conservation status following IUCN criteria indicated that arapaima populations in the upper Essequibo basin in 2001 would have been considered borderline Critically Endangered, but in 2013 after conservation interventions, status would be categorized as Near Threatened.
5. Arapaima in the Essequibo basin appear to favour larger but shallow lakes with low conductivity, clear water, and abundant aquatic macrophytes. Stock–recruitment relationships suggest that the entire upper Essequibo basin population may still be growing and that there is approximately a 1:1 juvenile to adult ratio. This ratio of juveniles to adults across all areas suggests a paucity of young fishes to sustain overall population growth, which might reflect widespread illegal removals of young fishes in the basin.
6. Comparisons of arapaima densities in the upper Essequibo basin with those at four localities across the Amazon Basin, suggest that with enhanced conservation efforts in the Essequibo, populations could potentially increase two-fold or more.

     

Maintenance of genetic variation in hatchery stocks of Atlantic salmon, Salmo salar L.: experiences from the River Bush, Northern Ireland

Abstract. An examination of biochemical-genetic variation at seven polymorphic loci was carried out among five year classes of wild Atlantic salmon, Salar L., in the R. Bush and in a hatchery strain derived from the wild population. Within some of the year classes, gene frequencies at several loci differed significantly between wild and artificially reared salmon. Highly significant temporal variation in gene frequencies was detected among successive year classes of the hatchery strain, while this was less significant among the wild salmon. Samples of wild salmon taken as 0+ and 1 + parr in the river showed no significant temporal variability in allelic frequencies. Heterozygosity levels among the wild and hatchery-reared salmon were comparable, averaging 0·185 and 0·176 respectively. The genetic variability of the artificially reared salmon is discussed in relation to numbers of broodstock and breeding regime used at the hatchery.     

Fisheries,large‐scale trade,and conservation of seahorses in Malaysia and Thailand

• 1. All seahorse species (genus Hippocampus) are listed under CITES Appendix II, requiring that exports of these fishes must be regulated for sustainability. Preliminary trade surveys and anecdotal reports suggested Malaysia and Thailand represented an important source for seahorses used globally in traditional medicine, curios, and aquarium display, but few historic trade or fisheries data are available. Baseline information about pre‐CITES catch and trade is essential for managing seahorse fisheries and trade under CITES, and for understanding present‐day effects of CITES regulation on the seahorse trade.
• 2. In 1998–1999, seahorse fisheries and trade in both countries were assessed by interviewing participants at many levels of the trade and corroborating those surveys with official trade documents.
• 3. Seahorses were found to be landed primarily as trawl bycatch. Malaysia's catch of 2900 kg year^?1 was less than the estimated domestic consumption (5500–6000 kg year^?1), whereas Thailand's catch of 6600 kg year^?1 apparently far exceeded domestic consumption (～520 kg year^?1).
• 4. Both countries imported seahorses from and exported to other Asian nations. Import statistics from Hong Kong SAR and Taiwan recorded maximum annual trade from Malaysia at 1280 kg year^?1. Trade surveys indicated that Thailand exported at least 5000 kg annually (similar to the estimation of catch), but national Customs records reported 10 500 kg year^?1 in exports, supported by official import records from Hong Kong SAR and Taiwan which indicated that Thailand was the source of up to 11 400 kg year^?1.
• 5. Fishers and traders in both countries reported decreasing availability of seahorses, raising conservation concerns. These apparent declines, in combination with substantial domestic consumption, point towards the challenges that Malaysia and Thailand face in establishing sustainable levels of exports under CITES. Copyright © 2010 John Wiley & Sons, Ltd.

     

Aquatic macroinvertebrates and environmental gradients in Phragmites reedswamps: implications for conservation

1. Aquatic macroinvertebrates were sampled from 22 sites in three contrasting reedswamps in the Burry Inlet, south-west Wales, which were respectively estuarine and tidal (Llangennech), coastal and artificial (Ashpits), and inland freshwater (Ffrwd). Species assemblages were ordinated by DECORANA, classified by TWINSPAN and related to physico-chemical factors using correlation, ANOVA and principal components analysis. 2. Reedswamps were not physico-chemically uniform, but varied in dissolved oxygen, nitrogen species, conductivity, water depth and reed character. 3. Among these factors, invertebrate species characteristic of the TWINSPAN groups suggested that conductivity, due to salinity, was an important influence on community composition; different communities were dominated by stenohaline to facultative euryhaline species, or by those characteristic of freshwater. Also, conductivity varied highly significantly across TWINSPAN groups: saline sites supported a higher abundance of fewer taxa, while freshwater sites were characterized by speciose assemblages with more beetles. 4. While major changes due to salinity occurred between and within reedswamps, different reedswamps nevertheless held distinct communities. This suggestion of ‘island’ effects prompts further data on aquatic invertebrates in reedswamps as part of the ‘SLOSS’ debate on their conservation. 5. These data show how salinity in maritime reedswamps provides strong habitat diversity in what appear superficially to be uniform habitats, with importance for example to general site design or managed retreat. The data also reveal that risks to speciose freshwater communities in such sites might arise from tidal inundation or sea level change. © 1997 John Wiley & Sons, Ltd.     

Status of galaxiid fishes in Tasmania,Australia: conservation listings,threats and management issues

• 1. Fish of the family Galaxiidae are restricted to the southern hemisphere where they occupy a diverse array of habitats ranging from over 2000 m in elevation to sea level. Some species are diadromous and, hence, freshwater, estuarine and marine habitats are used during their life‐cycle; other species complete their entire life‐cycles in freshwater environments.
• 2. Tasmania has a diverse galaxiid fauna that accounts for 64% of native freshwater fish species found on the island. The Tasmanian galaxiid fauna is characterized by high species richness (5 genera and 16 species), endemism (11 species), restricted distributions, and non‐diadromous life histories (11 species).
• 3. The galaxiid fauna of Tasmania has significant conservation status with 69% of species considered ‘threatened’. The conservation status of the fauna is recognized at State, national and international levels.
• 4. The key threats to galaxiids in Tasmania are exotic species, hydrological manipulations, restricted distributions, general habitat degradation and exploitation of stocks.
• 5. Although work has recently been undertaken to conserve and manage Tasmanian galaxiid populations, the fauna is still thought to be imperilled. Knowledge gaps that need to be addressed include the biology and ecology of most species (e.g. reproductive biology, life histories, habitat use and requirements) and impacts of habitat manipulations, as well as mechanisms and impacts of interactions with exotic species. Techniques to monitor accurately the status of galaxiid species and their populations need to be developed and the coexistence of some galaxiids with introduced salmonids should also be examined.

Copyright © 2005 John Wiley & Sons, Ltd.