نتایج جستجو برای: fish biodiversity
تعداد نتایج: 138899 فیلتر نتایج به سال:
Freshwater biodiversity is under threat worldwide, but the intensity of threat in the Oriental biogeographic region of tropical Asia is exceptional. Asia is the most densely populated region on Earth. Many rivers in that region are grossly polluted, and significant portions of their drainage basins and floodplains have been deforested or otherwise degraded. Flow regulation has been practiced fo...
Change in oceanographic conditions causes structural alterations in marine fish communities, but this effect may go undetected as most monitoring programs until recently mainly have focused on oceanography and commercial species rather than on whole ecosystems. In this paper, the objective is to describe the spatial and temporal changes in the Barents Sea fish community in the period 1992-2004 ...
Despite increasingly sophisticated microbiological techniques, and long after the first discovery of microbes, basic knowledge is still lacking to fully appreciate the ecological importance of microbial parasites in fish. This is likely due to the nature of their habitats as many species of fish suffer from living beneath turbid water away from easy recording. However, fishes represent key ecos...
Fish species from the subfamily Leuciscinae are an important part of the European ichthyofauna. The abundance of this fish group has decreased in some natural populations because of human impact and partly by interspecific hybridization. The objective of the present study was to use the ITS-1 rDNA spacer for identification of the European chub, the common dace and the ide. The examination was c...
'How many species are there?' is a basic question about life. From Acoela worms to Zoantharia corals, oceans are taxonomically more divergent than land. Answering the question requires many experts.
Effects of fragmentation on the ecology of organisms occupying dendritic ecological networks (DENs) have recently been described through both conceptual and mathematical models, but few hypotheses have been tested in complex, real-world ecosystems. Stream fishes provide a model system for assessing effects of fragmentation on the structure of communities occurring within DENs, including how fra...
While the collection of fish for the aquarium pet trade has been flagged as a major threat to wild populations, this link is tenuous for the unregulated wild collection of endemic species because of the lack of quantitative data. In this paper, we examine the extent and magnitude of collection and trade of endemic and threatened freshwater fishes from India for the pet markets, and discuss thei...
biological indicators are species that can be employed to monitor environmental quality and ecosystem health. different groups of organisms such as plants, animals, bacteria and parasites regularly produce certain molecular signal in response to changes in their environmental milieu. parasites are important tools for providing wealth of information on physicochemical quality, environmental stre...
qanat is one of the important inland aquatic ecosystems commonly containing freshwater in arid and semi-aridregions. there are 37 qanat chains in kerman county in the kerman province of iran. during past years, some ofthem have been dried as a result of deep wells digging in their vicinities. the present study used morphomeristicanalysis to characterize fishes and invertebrate fauna in the qana...
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