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排序方式: 共有960条查询结果,搜索用时 15 毫秒
1.
PAOLO GUIDETTI SIMONETTA FRASCHETTI ANTONIO TERLIZZI FERDINANDO BOERO 《Conservation biology》2004,18(5):1417-1423
Abstract: We surveyed shallow, rocky reefs in southwestern Apulia (Mediterranean Sea) to assess the effects on coastal fish assemblages of the date mussel ( Lithophaga lithophaga ) fishery, an illegal practice that strips the rocky reef bare. We visually sampled fish four times over 15 months at three locations, one affected by date-mussel fishery and two controls. The fish assemblage at the affected location differed significantly from those at the control locations over all sampling times. Herbivorous fishes, sparids, and labrids (genus Symphodus ) contributed most to the differences between the affected location and controls. Lower densities of Symphodus spp. were observed at the affected location, whereas detritivorous fishes were recorded exclusively at control sites. Small serranids and sparids showed temporal trends that differed between the affected location and the control locations. Our results suggest that the date-mussel fishery affects fish assemblages chiefly through reduction of arborescent macroalgae (contributing to habitat complexity and primary production) and emphasize the need for more effective policing against this destructive practice. 相似文献
2.
Indices of abundance and reproduction rate are considered in some groups of aquatic and terrestrial vertebrates from the zones of technogenic disasters. Upon a critical population decline caused by external destructive factors, such as emissions of acute ecotoxicants, the ecophysiological and behavioral compensatory mechanisms are activated, which provide for restoration of the total population size to the optimum within a short period of time. Environmental pollution with substances disturbing the reproductive function has the gravest consequences for animals. In this case, population size may remain fairly high, and, therefore, the effect of enhanced reproduction as a response to population decline does not take place, which eventually leads to a gradual but irreversible destruction of the population. Pathologies of reproduction should be used as a criterion for assessing the state of animals in the zones of technogenic disasters.Translated from Ekologiya, No. 1, 2005, pp. 32–38.Original Russian Text Copyright © 2005 by Shilova, Shatunovskii. 相似文献
3.
Thomas W. May Michael J. Walther Jimmie D. Petty James F. Fairchild Jeff Lucero Mike Delvaux Jill Manring Mike Armbruster David Hartman 《Environmental monitoring and assessment》2001,72(2):179-206
The Republican River Basin of Colorado,Nebraska, and Kansas lies in a valley which contains PierreShale as part of its geological substrata. Selenium is anindigenous constituent in the shale and is readily leached intosurrounding groundwater. The Basin is heavily irrigated throughthe pumping of groundwater, some of which is selenium-contaminated, onto fields in agricultural production. Water,sediment, benthic invertebrates, and/or fish were collected from46 sites in the Basin and were analyzed for selenium to determinethe potential for food-chain bioaccumulation, dietary toxicity,and reproductive effects of selenium in biota. Resultingselenium concentrations were compared to published guidelines orbiological effects thresholds. Water from 38% of the sites (n = 18) contained selenium concentrations exceeding 5 g L-1, which is reported to be a high hazard for selenium accumulation into the planktonic food chain. An additional 12 sites (26% of the sites) contained selenium in water between 3–5 g L-1, constituting a moderate hazard. Selenium concentrations in sedimentindicated little to no hazard for selenium accumulation fromsediments into the benthic food chain. Ninety-five percent ofbenthic invertebrates collected exhibited selenium concentrationsexceeding 3 g g-1, a level reported as potentially lethal to fish and birds that consume them. Seventy-five percent of fish collected in 1997, 90% in 1998, and 64% in 1999 exceeded 4 g g-1selenium, indicating a high potential for toxicity andreproductive effects. However, examination of weight profilesof various species of collected individual fish suggestedsuccessful recruitment in spite of selenium concentrations thatexceeded published biological effects thresholds for health andreproductive success. This finding suggested that universalapplication of published guidelines for selenium may beinappropriate or at least may need refinement for systems similarto the Republican River Basin. Additional research is needed todetermine the true impact of selenium on fish and wildliferesources in the Basin. 相似文献
4.
厦门西港海水质量对鱼卵胚胎发育畸形率的影响 总被引:3,自引:1,他引:3
以养殖场培育的花尾胡椒鲷受精卵为实验材料测试了厦门西域5个站位的表层水水样对花尾胡椒鲷受精卵的胚胎发育毒性,并运用GC-MS手段分析了水样中的美国EPA优控的16PAHs组分的含量。结果表明:3号站位(厦门市工业和生活污水主要排放口的外侧)和4号站位(厦门西港的港区)的水样对鱼卵的胚胎发育的毒性最强。8号站位(位于主航道并濒临嵩屿电厂)的水样对鱼卵胚胎发良的毒性次之,1号站位(湾口)和5号站位(内港)的水样对鱼卵的胚胎发育的毒性较小。水样中的PAHs含量分析结果表明,仅用水样中的PAHs含量不能全面地反映水样对鱼卵胚胎发育的毒性。最后,对本实验方法应用于海洋环境生物监测的有效性进行了探讨。 相似文献
5.
6.
利用生物指示物(鳙鱼)对丹东地区鸭绿江水体中的铅、镉污染进行监测,采具鳙鱼-碳化酸溶-电热原子光谱法对丹东鸭绿江流域鳙鱼体内的铅、镉的含量进行了相关检测,在相同的实验条件下对该地区的水体中的铅、镉的含量进行对比,并对该地区的铅、镉污染进行了相关的评价,通过一年的监测未见超标。铅、镉含量分别为6.53±0.07(ng/g)、4.60±0.03(ng/g);回收率分别为98.9%、103.5%;RSD分别为5.3%、4.1%。 相似文献
7.
Cutler P 《Disasters》1984,8(1):48-56
This paper, completed in January 1984, begins by briefly outlining the contrasting views of price behaviour during the last Ethiopian famine (1972–1974) put forward by Seaman and Holt (1980) and Sen (1981). A hypothesis is developed to account for peasant behaviour and price responses under developing famine conditions. This is then tested with data recently made available. The paper concludes by summarizing the findings and their implications for famine forecasting, and argues that famine conditions in Northern Ethiopia are likely to worsen during 1984. 相似文献
8.
9.
以松花江流域的野生鱼类为研究对象,在松花江流域选取松林、大顶子山、佳木斯3个具有代表性的点位,在2014—2016年的每年5月底6月初采集鲤鱼和鲫鱼样品,3年内共制备45个鲤鱼单样,44个鲤鱼混样,30个鲫鱼混样,共计119个。采用电感耦合等离子体-质谱法对鱼类肌肉组织中残留的As、Cd、Cr、Pb、Hg 5种重金属进行检测。检测结果显示,As、Cd、Cr、Pb、Hg 5种重金属全部检出,检测结果全部达标,达标率为100%。根据检测结果采用单因子指数法和金属污染指数法等评价了松花江流域鱼体重金属残留状况及食用安全性,评价结果为松花江流域鱼类重金属残留量相对较少,鱼体健康,食用安全。 相似文献
10.
苯并(a)芘在四种食用淡水鱼中的含量和分布 总被引:2,自引:1,他引:1
利用GC-MS测定了购自北京市场的4种食用淡水鱼(鲫鱼、胖头鱼、鲤鱼、草鱼)的5种组织器官(脑、肝、泡、卵和肌肉)中BaP的含量,分析了BaP在4种食用淡水鱼中的分布特征及其对人体的健康风险.结果表明,鱼体BaP湿重含量范围为0~0.057ng·g-1,BaP脂标化含量范围为0.02~21·22 ng˙g-1·BaP在不同组织器官和不同鱼种中的湿重含量差别不显著;而不同鱼种和组织器官中BaP脂标化含量则有一定的差异性.4种鱼中,胖头鱼BaP脂标化含量水平最高,鲫鱼次之,草鱼和鲤鱼较低;各组织器官中,肝脏的BaP脂标化含量相对最高,肉、泡、籽次之,脑中BaP脂标化含量相对最低.鱼体中BaP湿重含量均低于USEPA规定的可食用生物组织器官中BaP含量的上限值(0.67 ng·g-1,wetweight),对人体的致癌风险远小于10-5. 相似文献