نتایج جستجو برای: fresh water catfish
تعداد نتایج: 600497 فیلتر نتایج به سال:
Channel catfish from two strains, USDA-103 and Norris, were reared in circular 800-l tanks Ž . and injected once weekly with 2.5 mg recombinant bovine growth hormone rbGH per gram body weight, or the saline vehicle. In addition to the rbGH, and strain treatments, half the tanks were supplied with well water of 26.08C and the other half received water of 21.78C. Growth rate, Ž . plasma insulin-l...
The present study was undertaken to evaluate the influence of butachlor, a widely used herbicide, on antioxidant enzyme system and lipid peroxidation formation in African cat fish (Clarias gariepinus). Fish were exposed to sub-lethal concentrations of butachlor 1, 2, 2.5 ppm and sacrificed 24hrs after treatment. A significant increase in malondialdehyde formation was observed in the liver, kidn...
—A 9-week growth study was conducted to compare the fingerling performance of two genetic groups of channel catfish Ictalurus punctatus (U.S. Department of Agriculture [USDA] 103 and USDA303) with that of blue catfish I. furcatus and their hybrid in an aquarium rack system. Fish of approximately 20 g were randomly selected from multifamily populations and acclimated to the aquarium rack system ...
The mainly fresh water arboviral vector Aedes aegypti L. (Diptera: Culicidae) can also undergo pre-imaginal development in brackish water of up to 15 ppt (parts per thousand) salt in coastal areas. We investigated differences in salinity tolerance, egg laying preference, egg hatching and larval development times and resistance to common insecticides in Ae. aegypti collected from brackish and fr...
Kinetics of trace metal competition in the freshwater environment: some fundamental characteristics.
Freshwaters are recognized as dynamic systems that may be far-removed from equilibrium. A kinetic approach using the competing ligand exchange method with Chelex 100 as the competing ligand and inductively coupled plasmamass spectrometry to measure the dissociation kinetics was used to investigate the chemical speciation of Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Pb(II) in model sol...
Different levels of eutrophication and pollution in the Baltic coastal waters in general, and in estuaries particularly define variations in the buffering capacity of ecosystems of these important filter zones between rivers and the adjacent Baltic Proper. Phyto- and zooplankton in the estuaries form important components of the pelagic food webs that participate in producing and structuring the...
Despite considerable increased pesticide use over the past decades, little research has been done into their fate and effects in surface waters in tropical regions. In the present review, possible differences in response between temperate and tropical freshwaters to pesticide stress are discussed. Three underlying mechanisms for these differences are distinguished: (1) climate related parameter...
Biological invasions have increased significantly in response to global change and constitute one of the major causes of biodiversity loss. Insects make up a large fraction of invasive species, in general, and freshwaters are among the most invaded ecosystems on our planet. However, even though aquatic insects dominate most inland waters, have unparalleled taxonomic diversity and occupy nearly ...
With the rapidly increasing demands on water resources, fresh water shortage has become an important issue affecting the economic and social development in many countries. As one of the main technologies for producing fresh water from saline water and other wastewater sources, reverse osmosis (RO) has been widely used so far. However, a major challenge facing widespread application of RO techno...
There is a gradual decline in soil fertility due to its continue use in farming. This necessitates developing new strategies of management programs to recharge soil with nutrients. From review it has been found that reuse of industrial effluents (wastewater) in agriculture can be a good mode to conserve soil nutrients. It may offer a way to fulfill irrigation water demands also. The major chall...
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