外来水产动物引进的风险评估体系的构建与应用

外来水生生物入侵被认为是导致我国水生生态系统生物多样性破坏的主要因素之一,同时阻碍了我国水产养殖业的健康发展。在众多造成水生生物入侵的因素中,外来水产动物的引进是重要因素之一,其中不仅包括外来物种自身造成的生物入侵,也包括外来物种携带的病原生物对本土物种、生态环境、人类健康等造成的巨大威胁。为了对待引入外来水产动物的风险进行科学评估,根据分析常见外来水生动物可能存在的入侵机制与生态风险,利用层次分析法和成对比较矩阵方法对指标权重进行计算,构建了外来水产动物引进的风险定量评估体系。该评估体系包括6个一级指标(即外来种自身性质、外来种生态风险、病原生物入境、病原生物暴露、危害与影响、外来种风险防控)和32个二级指标。利用该评估体系对我国境内现有的三种外来水产动物进行定量的风险评估,评估结果显示：鳄雀鳝(Atractosteus spatula)的风险值R为3.5975,为高风险等级;虾夷扇贝(Mizuhopecten yessoensis)风险值R为2.7823,为中风险等级;锦绣龙虾(Panulirus ornatus)风险值R为1.9568,为低风险等级。该评估结果与我国农业农村部、生态环境部、海关总署等相关单位提供的资料高度吻合,说明该模型在外来水产动物引进与养殖风险评估的相关工作中有重要的应用价值。     

莱州湾泥螺生态安全风险评估——基于AHP的YAAHP软件实现

以莱州湾西岸外来物种泥螺为例,运用YAAHP软件,采用层次分析法(AHP)对其生态安全风险进行了评估。以泥螺完整的生物入侵过程为依据,针对各阶段的关键特性,综合考虑外来物种的生物学、生活史特征、人为干扰影响因素、入侵地的生态系统状况等方面来选取评估指标,设计6个一级指标,30个二级指标,设定了"可以引种"、"引种具有一定风险"和"禁止引种"3个风险分级标准,构建了风险评价指标框架。通过对历史文献资料的分析、专家评分以及必要的调查实验等方法,对风险评估层次结构模型各项指标进行权重赋值。软件分析的结果显示,"具有一定风险"的权重值最高,为0.507 6,其次为"可以引种",权重值为0.352 2,而"禁止引种"的权重值仅为0.140 2,因此,得出的最终方案为引种具有一定的风险。本研究对占权重值较高的传入风险、定殖风险和扩散风险3项指标进行了灵敏度分析,结果表明,3种指标的权重只影响评估结果的"具有一定风险"和"可以引种"的排列顺序,而不会影响"禁止引种"。因此建议,切勿盲目扩大泥螺的养殖规模,引入之后必须加强监督和管理。     

以嘉陵江为例构建并分析有毒鱼类风险评估体系

摘要：为提高人们对淡水有毒鱼类的认知、增强公众的防范意识、减少不必要的损失,也为有毒鱼类的深入研究奠定基础,本研究初步构建了有毒鱼类风险评估体系,并对嘉陵江已知的18种有毒鱼类展开应用探索。该风险评估体系从有毒鱼类毒性属性、群体属性以及社会属性展开,共包括3个一级指标、8个二级指标和26个三级指标。通过对各有毒鱼类的各指标赋值,其后,根据各指标已确定的权重,从而得出各有毒鱼类的风险评估值,确定其风险等级。结果显示,在嘉陵江已知的18种有毒鱼类中,有4种被界定为高风险有毒鱼类,包括草鱼、鲤、鲇以及鳜,其余14种皆为中风险有毒鱼类。卡方检验（χ2）结果表明,嘉陵江不同风险等级有毒鱼类在食性类别、分布水层、分布范围及繁殖特征上差异不显著（P＞0.05）。该评估体系具有一定的实用价值,但限于对有毒鱼类的认知,本评估体系难免存在不足,未来应当加强对有毒鱼类的研究,以不断地完善该评估体系。本研究加强了人们对于有毒鱼类的了解,为有毒鱼类的科学管理提供了支撑,同时,也为下一步研究奠定了基础。     

赤潮灾害风险评估方法研究——以辽宁近岸海域为例

以赤潮灾害风险理论为依据,结合辽宁沿海城市近70年长期赤潮灾害历史资料数据,建立了辽宁近岸赤潮灾害风险评估指标体系,运用熵权法及层次分析法分析指标权重,构建了危险度指数、承灾体脆弱性指数灾害风险评价模型,最后,利用自然灾害风险分级矩阵方法进行灾害风险分级。风险评估结果显示,辽宁沿海城市大连市属于极高风险等级,丹东市、营口市、葫芦岛市属于中风险等级,盘锦市和锦州市处于较低风险等级。评价结果与近十年赤潮灾害历史统计数据基本吻合,该方法的建立对辽宁近岸海域赤潮灾害风险界定及防治具有重要意义。     

辽宁近海外来赤潮海洋微藻入侵现状

<正>外来海洋生物入侵已成为全球性的环境问题之一,而生物入侵对生态系统稳定性的影响以及经济损失,已经引起科学界和社会公众的广泛关注。20世纪及21世纪初运输船舶压舱水排放等导致外来海洋浮游生物广泛传播。本文主要通过收集中国生物多样性数据库、中国外来入侵物种数据库、中国外来海洋生物入侵数据库、全球入侵物种数据库美国海岸警戒压舱水管理项目数据库资料及相关文献,结合辽宁近海历史与近期的调查资料,综     

湖北省典型湖泊湿地生物多样性评价研究

计算并比较湖泊的生物多样性指数和评价等级,为湖北省湖泊湿地生物多样性保护和管理提供参考依据。10个湖泊为洪湖、梁子湖、长湖、斧头湖、龙感湖、保安湖、网湖、东湖、沉湖和涨渡湖,选取物种多度、物种相对丰度、稀有物种、群系多度、湿地类型、保护地类型、外来物种入侵、植物破坏程度、保护意识和管理水平等9项评价指标构建湖泊湿地生物多样性评价体系,指标权重通过专家咨询法与层级分析法确定。结果表明:10个湖泊湿地生物多样性指数分别为洪湖81.2、梁子湖73.3、沉湖67.8、龙感湖65.6、网湖64.6、涨渡湖49.4、长湖48.6、斧头湖42.7、东湖44.0、保安湖37.1;生物多样性等级洪湖为"丰富";梁子湖、龙感湖、沉湖为"较丰富";长湖、网湖、涨渡湖为"一般";斧头湖、保安湖、东湖为"较贫乏"。分析了生物多样性较低的湖泊湿地存在的主要问题,并提出了保护建议。     

中国水生外来物种入侵现状和对策

水生外来物种入侵是指某物种在某水域生态系统中原来没有,通过人为有意或无意活动从其它生态系统中引入,一旦该物种在当地形成自己繁殖,并对当地生态或者经济造成破坏,该物种就构成了水生外来物政策导航责任编辑肖乐种入侵。入侵种可能是水生植物或者动物,也可能是一种病毒或细菌。水生外来物种一旦入侵成功,将对当地水生物种的种类、种群结构、食物链结构、生物多样性等产生一系列的影响,威胁渔业生产、经济和生态安全。我国水生外来物种入侵现状我国水生外来物种入侵的总体状况近20年来,随着水产养殖、水簇产业的发展以及资源增殖放流的需…     

五部委发布《方案》就加强外来物种入侵防控工作作出进一步要求

正本刊讯2月3日,经国务院同意,农业农村部、自然资源部、生态环境部、海关总署、国家林草局五部门印发《进一步加强外来物种入侵防控工作方案》(以下简称《方案》)。《方案》指出,要开展外来入侵物种普查和监测预警。以我国初步掌握的外来入侵物种为基础,在农田、渔业水域、森林、草原、湿地等各区域,启动外来入侵物种普查,通过3年左右的时间,摸清我国外来入侵物种的种类数量、分布范围、危害程度等情况。依托国土空间基础信息平台等构建监测预警网络,在边境地区及主要入境口岸、粮食主产区、自然保护地等重点区域,以农作物重大病虫、林草外来有害生物为重点,布设监测站(点),组织开展常态化监测。     

规范水产苗种引进防止外来物种入侵

随着全国性清查食人鱼活动的全面展开,食人鱼作为一个外来入侵种正在悄悄地退出中国、退出我们的视野和生活。但是食人鱼并不是我国第一个外来入侵种,也不会是最后一个。外来物种在进入我国境内时如入无人之地,没有任何阻挡的事实,说明了我国对外来物种监管工作的薄弱。食人鱼的风波虽已逐渐平息,但它留给我们许多启示,许多问题令人深思、反醒。一、食人鱼清查对加强水产苗种管理工作的启示。(一)全面清查食人鱼,防患于未然为加强对外来水生物种的监督管理,保障物种安全,防止外来物种入侵对我国水域生态环境的破坏,2002年12月24日,中华人民…     

西藏雅鲁藏布江中游裂腹鱼类优先保护等级定量评价

西藏地区雅鲁藏布江中游分布有6种特有裂腹鱼类,是地方重要的土著经济物种。近年来,受人类活动和环境变化的影响,裂腹鱼类资源已严重衰退而处于濒危,急需开展裂腹鱼类的资源现状调查及保护等级评价工作。本课题组分别于2015年和2017年的春季(4—5月),对雅鲁藏布江中游的渔业资源进行调查监测,参阅相关文献资料,采用珍稀性、物种价值和人为干扰共3个一级指标和5个二级指标建立优先保护等级的定量评价体系,对6种裂腹鱼类的资源状况及濒危状况进行评价,根据评分标准与优先保护综合评价值(R)确定裂腹鱼类的优先保护等级。研究结果表明,尖裸鲤(Oxygymnocypris stewartii)为一级优先保护鱼类,双须叶须鱼(Ptychobarbus dipogon)为二级优先保护鱼类,拉萨裂腹鱼(Schizothorax waltoni)和巨须裂腹鱼(Schizothorax macropogon)为三级优先保护鱼类,异齿裂腹鱼(Schizothorax o’connori)和拉萨裸裂尻鱼(Schizopygopsis younghusbandi)为四级优先保护鱼类。评价分级结果与实际情况相符,真实地反映了6种裂腹鱼类优先保护顺序。本研究对雅鲁藏布江中游的鱼类保护等级提出建议,为鱼类资源的科学保护管理等提供参考和依据。     

Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean

The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.     

Growth performance,digestive enzyme activity and immune response of Japanese sea bass,Lateolabrax japonicus fed with fructooligosaccharide

In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.     

Rare serotype occurrence and PFGE genotypic diversity of Streptococcus agalactiae isolated from tilapia in China

Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China.     

Evaluation of a Fast Method Based on the Presence of Two Restriction Sites in the Mitochondrial ND5 (mt ND5) Gene for the Identification of Scomber Species

The purpose of this work was to evaluate the suitability of a method based on the presence of two restriction sites (for Hae III and Hindf I) in the mitochondrial NADH dehydrogenase subunit 5 (mt ND5) gene to identify Scomber species. The evaluation was performed on 144 reference and market samples by sequencing of the entire 505-bp fragment of the mt ND5 gene and of a 464-bp fragment of the Kocher fragment of the cytochrome b gene (mt Cytb). Sequence analysis of any of the two fragments allows the identification of each of the four Scomber species, but S. japonicus and S. colias had the same restriction sites at the ND5 amplicon and would not have been differentiated by this analysis. Similarly, loss of the Hae III site in some S. scombrus individuals would have misidentified them as not being Scomber. All the market products were correctly labeled except one acquired in Spain labeled as originating in the Atlantic and containing S. japonicus.     

Growth hormone (GH) and reproduction: a review

Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations.     

Purification and partial characterization of GtHs (cfLH and cfFSH) from Indian walking catfish (Clarias batrachus) (L.) and development of a homologous ELISA for cfLH

Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL^?1 (1.25 ng well^?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation.     

Controlled infection of Poecilia reticulata Peters (guppy) with Tetrahymena by immersion and intraperitoneal injection

Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg^?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality).