نتایج جستجو برای: freshwater fishes
تعداد نتایج: 45711 فیلتر نتایج به سال:
Received on 27 July 2000 Accepted on 27 September 2000 Abstract The freshwater aquatic biodiversity is depleting alarmingly due to the introduction of exotic species and other anthropogenic activities. The indiscriminate transfer of exotic fishes has brought about a wide array of problems including extirpation of indigenous species. The exotics compete with the indigenous species for food, habi...
In a recent issue of Systematic Biology, Briggs (2003: Fishes and Birds: Gondwana Life Rafts Reconsidered, pp. 548–553) examines the current distributions of four vertebrate clades (cichlid fishes, aplocheiloid killifishes, ratites, and parrots), which have been attributed to the Mesozoic fragmentation of Gondwana (Parenti, 1981; Stiassny, 1991; Murphy and Collier, 1997; Farias et al., 1999). B...
Generating awareness of environmental conservation issues among the public is essential if there is an expectation of them to alter their behaviour, facilitate informed decisions and engage governments or regulatory authorities to take action. There are, however, exceedingly few public engagement success stories related to inland fishes and fisheries policy and resource allocation decisions. In...
Many of California's native populations of freshwater fish are in serious decline, as are freshwater faunas worldwide. Habitat loss and alteration, hydrologic modification, water pollution, and invasions have been identified as major drivers of these losses. Because these potential causes of decline are frequently correlated, it is difficult to separate direct from indirect effects of each fact...
Fishes can play important functional roles in the nutrient dynamics of freshwater systems. Aggregating fishes have the potential to generate areas of increased biogeochemical activity, or hotspots, in streams and rivers. Many of the studies documenting the functional role of fishes in nutrient dynamics have focused on native fish species; however, introduced fishes may restructure nutrient stor...
Fishes account for approximately 17% of the global animal protein intake. Fish and fishery products, however, have been documented as a carrier of food-borne pathogens. Fishes serve as a host to a variety of parasites including Salmonella.Salmonella, usually, is not a fish pathogen, rather the consumption of Salmonella contaminated feed and water causes this infection. Smoked fishes serves as a...
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...
Restriction-fragment length polymorphisms in mitochondrial DNA (mtDNA) were used to evaluate population-genetic structure and matriarchal phylogeny in four species of marine fishes that lack a pelagic larval stage: the catfishes Arius felis and Bagre marinus, and the toadfishes Opsanus tau and O. beta. Thirteen informative restriction enzymes were used to assay mtDNAs from 134 specimens collect...
In order to draw patterns in helminth parasite composition and species richness in Mexican freshwater fishes we analyse a presence-absence matrix representing every species of adult helminth parasites of freshwater fishes from 23 Mexican hydrological basins. We examine the distributional patterns of the helminth parasites with regard to the main hydrological basins of the country, and in doing ...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید