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1.
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。  相似文献   

2.
张富斌  王健  杨坤  高欣  曾燏 《水产学报》2022,46(9):1593-1603
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。  相似文献   

3.
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。  相似文献   

4.
湖北省典型湖泊湿地生物多样性评价研究   总被引:1,自引:0,他引:1       下载免费PDF全文
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。  相似文献   

5.
为评估石斑鱼养殖过程虹彩病毒病发生的风险,实验结合Delphi法和层次分析法(analytic hierarchy process, AHP)构建新加坡石斑鱼虹彩病毒(SGIV)发生的风险评估模型。风险因素评估指标体系包括1个目标层(石斑鱼虹彩病毒病发生风险),5个准则层(水质、石斑鱼健康状况、饲养管理、养殖模式和养殖环境)和20个指标层风险因素(水温、pH、溶解氧、氨氮、病毒感染、细菌感染等)。准则层风险因素权重值集合为W={0.129 8,0.367 2,0.173 3,0.032 7,0.297 1},指标层风险因素中病毒感染(0.248 5)、邻近区域发病情况(0.138 4)、水温(0.112 3)和养殖密度(0.105 0)等权重值较高,推测它们是影响石斑鱼虹彩病毒病暴发的高风险因素。进一步实验室模拟感染实验结果表明,养殖密度、病毒感染剂量及养殖温度均显著影响鱼体内新加坡石斑鱼虹彩病毒(SGIV)的复制及实验鱼死亡率。上述结论和评估模型中推定的高风险因素相吻合,说明该模型可用于石斑鱼养殖过程中虹彩病毒病发生的风险评估。  相似文献   

6.
随着经济的发展和运输的发达通畅,广东省东莞市近年来外来水生物种正逐渐增多。外来物种虽部分丰富了东莞的水产种质资源,为水产养殖业发展做出了重要贡献,但有些外来水生动物如果在江河中迅猛繁殖建立自己的种群将成为入侵物种,会使本地的物种面临减少甚至灭绝的危险,  相似文献   

7.
在淡水鱼类资源调查和外来物种采样监测中,广东江河发现的外来物种主要是罗非鱼、巴西龟、革胡子鲶、下口鲶(清道夫)等,几乎所有较大江河里都发现了它们的踪影,尤其是罗非鱼大量入侵自然生态体系。据渔民反映,在鉴江、袂花江捕捞渔获中罗非鱼占了总数的60%左右,在漠阳江所占的比例甚至更高。  相似文献   

8.
简述了我国常见的4种外来鲑形目物种大西洋鲑、虹鳟、金鳟和美洲红点鲑形态特征、生物习性、分布和养殖概况、扩散风险及防控建议等,对其形态差异性进行了对比。指出,外来水生生物在自然水域的繁衍和种群扩张会对本土原生物种、种群结构、群落结构及食物链产生系列连锁影响,威胁本土水域生态系统的安全和稳定。提出,应进一步健全外来物种海关监管机制,建立外来物种引种评估规范,制定外来水生生物放生、弃养处理办法,深化国际合作,建立跨界水域生态系统保护协作机制。最终实现合理利用外来物种、保护国门生物安全、国内生态和种质资源安全的目标。  相似文献   

9.
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。  相似文献   

10.
《海洋与渔业》2013,(3):30-31
2012年7月,位于珠江流域上游的广西柳州柳江内,一起“食人鲳”伤人事件引发了公众对外来物种的强烈关注,并再次让社会感受到外来物种入侵带来的威胁。近几年来,媒体公开报道了多起我国发现外来水生物种消息。  相似文献   

11.
12.
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.  相似文献   

13.
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.  相似文献   

14.
Growth hormone (GH) and reproduction: a review   总被引:5,自引:0,他引:5  
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.  相似文献   

15.
16.
Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg?1 protein) than essential amino acids (425.82 ± 9.15 g kg?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting.  相似文献   

17.
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.  相似文献   

18.
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.  相似文献   

19.
The endemic, anadromous cyprinidChalcalburnus tarichi is the only fish species known to occur in alkaline Lake Van (Eastern Anatolia, Turkey). EightC. tarichi were maintained individually in Lake Van water (17 – 19°C; pH 9.8; 153 mEq·I–1 total alkalinity; 22 total salinity) and tank water samples analyzed for 24 h in 2 to 4 h intervals. At zero time, < 1µM ammonia was present and urea was undetectable in the tank water; at 24 h, total ammonia and urea made up 114±32 and 35±25µM, respectively. Over the experimental period, ammonia-N and urea-N excretion averaged 1041±494 and 607±169moles·kg–1 fish·h–1, respectively. The extent of urea excretion was highly variable between specimens. Uric acid excretion was not detectable.Urea was present at high concentrations in all tissues and plasma (25 – 35moles·g–1·ml–1) of freshly caughtC. tarichi; total ammonia content of the tissues was by a factor of 1.9 (liver) to 3.0 (brain) lower. High arginase activity (2.4±0.2 U·min–1·g–1) was detected in the liver ofC. tarichi but ornithine carbamoylphosphate transferase, a key enzyme of the ornithine-urea-cycle, was absent. Ureagenesis is likely through degradation of arginine and/or uricolysis. High glutamine synthetase activity (11±0.6 U·min–1·g–1) and low ammonia content in brain suggest that, like other teleosts,C. tarichi has an efficient ammonia detoxification in the brain, but in no other tissue.Nitrogenous waste excretion at alkaline pH is discussed. The ability ofC. tarichi to excrete high levels of ammonia at extremely alkaline pH is unique among teleosts studied so far. The mechanism of ammonia excretion under Lake Van conditions remains to be elucidated.  相似文献   

20.
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).  相似文献   

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