引进外来物种的环境风险评价初探——以美国斑点叉尾鮰为例

随着我国经济的发展以及全球经济一体化,使得国际贸易往来越来越频繁,为外来物种迁移、传播、扩散创造了条件,对当地生态安全带来了较大的影响,一旦发生生物入侵,将对社会与环境造成巨大的损失。以从美国引进的斑点又尾鮰为例,从生物学特征、相关试验情况、生态安全的影响、风险管理等方面进行了环境风险评估,并提出了风险防范管理措施。     

斑点叉尾(鱼回)生物学研究

斑点叉尾(鱼回)为原产于美洲的大型经济鱼类,美国自二十世纪60年代开始商业养殖,我国于1986年引进.我们对其进行了三年的研究,在观察解剖的基础上,系统总结了斑点叉尾(鱼回)的生物学特点.     

斑点叉尾(鱼回)的防御机制

斑点叉尾(鱼回)的特异性与非特异性防御机制,是抵抗病原体入侵和促使病鱼康复的二大互相依赖又各自独立的防御系统,对养鱼生产实践有一定的指导作用。本文简要对这二大系统分别进行论述。     

斑点叉尾(鱼回)的营养需求量

本文阐述了斑点叉尾(鱼回)对蛋白质、脂肪、糖类、维生素及微量元素等各种营养的需求量,为养殖者寻求适宜、廉价的饵料和合理的养殖方式提供了参考。     

斑点叉尾(魚回)源嗜麦芽寡养单胞菌胞外产物的生物学特性与致病性研究

本实验对斑点叉尾(魚回)源嗜麦芽寡养单胞菌(Stenotrophomonas maltophilia,Sma)胞外产物(Extracellular products,ECP)的生物学特性及其致病性进行了研究.结果表明,Sma胞外产物具有脂肪酶、蛋白酶、明胶酶和脲酶等多种酶活性;同时具有溶血活性、肠毒性和Vero细胞毒性;且对小鼠和斑点叉尾(魚回)都具有明显的致病性和致死性.     

网箱饲养斑点叉尾鱼回技术

根据实践经验和有关资料,阐述了网箱饲养斑点叉尾鱼回的技术,内容包括放养、饵料及其投喂、鱼病防治及活鱼运输等     

广西地区斑点叉尾(鱼回)人工繁殖试验

从池塘养殖的成鱼中选择亲鱼,培育至3龄以上,自然受精、人工孵化.4月上旬获第1批受精卵,经4 d室内孵化,出苗36万尾,培育至7～8cm32.4万尾,成活率达90%.比湖北地区产苗时间提前1个多月.     

斑点叉尾鱼回池塘工业化生态养殖模式经济效益及评价

为研究生态高效的水产养殖模式,对现有的养殖模式进行优化和创新,在面积8 670 m²的池塘中构建了工业化养殖系统,主养区养殖斑点叉尾鱼回,净水区养殖鲢鳙等滤食性鱼类,并栽种水生经济植物,通过182 d的养殖试验,对斑点叉尾鱼回池塘工业化生态养殖模式的经济效益和养殖效果进行分析和评价。试验结果:该养殖模式总产值247 482.8元,生产总投入178 694.5元,养殖利润68 788.3元。经折算,每667 m²投入成本13 745.7元,养殖利润5 292元。     

罗坑库湾养殖斑点叉尾(鱼回)技术初探

土拦库湾0.53 hm2,最大水深3 m,投放13 cm的斑点叉尾( )苗种6000尾,养殖时间约7个月,捕捞产量1 100kg,库存3 125kg,支出4.50万元,总收入8.45万元,纯收入3.95万元,投入产出比1∶1.88.大水面放养(鱼回)鱼,增值潜力巨大.     

斑点叉尾触病毒性疾病综述

本文综述了斑点又尾(鱼回)主要的病毒性疾病的流行情况、临床症状、诊断和治疗措施等,以期为斑点又尾(鱼回)的养殖生产和疾病防治提供参考依据。     

外来海洋物种入侵风险评估体系的构建

为了评估外来海洋物种入侵的风险,根据外来海洋物种入侵特点,在文献分析和专家咨询的基础上,采用层次分析和三角模糊数数值标度计算权重的方法,设计5个一级指标和20个二级指标,构建了外来海洋物种入侵风险评估体系。利用该评估体系对7种（类）典型海洋外来种进行了风险评估。评估结果表明,互花米草和对虾白斑病毒为极高风险等级;沙筛贝、米氏凯伦藻和帕金虫为高风险等级,罗非鱼为中风险等级;大菱鲆为低风险等级。由于传统层次分析法的“1～9标度”方法不能精确地反映人的实际思维,从而影响最终的判定结果,本评估体系借鉴了三角模糊数表示的改进方法来计算权重值,并对一级指标和二级指标的相对权重均进行了权重设计,得出的结果更加精确地反映了人的实际思维。外来海洋物种入侵风险评估体系的建立将为外来海洋物种入侵风险管理提供决策依据和参考。     

Environmental and economic impact assessment of alien and invasive fish species in Europe using the generic impact scoring system

Invasions by alien species are one of the major threats to the native environment. There are multifold attempts to counter alien species, but limited resources for mitigation or eradication programmes makes prioritisation indispensable. We used the generic impact scoring system to assess the impact of alien fish species in Europe. It prioritises species, but also offers the possibility to compare the impact of alien invasive species between different taxonomic groups. For alien fish in Europe, we compiled a list of 40 established species. By literature research, we assessed the environmental impact (through herbivory, predation, competition, disease transmission, hybridisation and ecosystem alteration) and economic impact (on agriculture, animal production, forestry, human infrastructure, human health and human social life) of each species. The goldfish/gibel complex Carassius auratus/C. gibelio scored the highest impact points, followed by the grass carp Ctenopharyngodon idella and the topmouth gudgeon Pseudorasbora parva. According to our analyses, alien fish species have the strongest impact on the environment through predation, followed by competition with native species. Besides negatively affecting animal production (mainly in aquaculture), alien fish have no pronounced economic impact. At the species level, C. auratus/C. gibelio show similar impact scores to the worst alien mammals in Europe. This study indicates that the generic impact scoring system is useful to investigate the impact of alien fish, also allowing cross‐taxa comparisons. Our results are therefore of major relevance for stakeholders and decision‐makers involved in management and eradication of alien fish species.     

Modelling effects of invasive species and drought on crayfish extinction risk and population dynamics

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Ecological risk assessment of species impacted by fisheries in waters off eastern Taiwan

An ecological risk assessment was undertaken using productivity‐susceptibility analysis (PSA) to determine the relative vulnerability of 52 species caught by fisheries in the waters off eastern Taiwan. Overall, eight and 20 species were classified as having high and moderate vulnerability, respectively, and the remaining 24 species were classified as having low vulnerability. The species with the highest vulnerability scores were caught mainly by longline and gillnet fisheries, highlighting the need for improved data collection to facilitate a more detailed investigation using more quantitative methods. The data quality analysis indicated that the quality of data was classified as “moderate” for economically important species. However, many species were considered data‐limited and thus collecting high‐resolution catch and effort information and conducting biological studies, especially relating to age, growth and reproduction, are recommended to improve the reliability of outputs from data‐limited assessments such as PSA.     

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Quantitative ecological risk assessment for fishing effects on diverse data-poor non-target species in a multi-sector and multi-gear fishery

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Weighting species abundance estimates for marine resource assessment

1. This paper describes a straightforward method for introducing species weightings into the calculation of a similarity matrix using the Bray–Curtis coefficient. Weighting may be required in order to provide differential emphasis in abundances on the basis of species' size, ecological importance, abundance or in mixing different data types. The similarity matrix can then be used for a range of multivariate analytical procedures, such as cluster analysis or ordination using non-metric multi-dimensional scaling (MDS). Such techniques are widely used for the identification of species' assemblages and habitats in marine resource and conservation assessment. 2. The weighting procedure was used to examine the effect of variable accuracy in species identification by trained volunteer divers conducting baseline surveys of reefal habitats in Belize. The accuracy of identification was found to vary asymmetrically between species. 3. The modified Bray–Curtis similarity coefficient was used to incorporate individual species weightings which are proportional to the frequency at which each species is correctly identified. The results of the study demonstrate the fundamental robustness of the Bray–Curtis similarity coefficient/multivariate approach which together, are insensitive to the asymmetric accuracy levels present in the data.