considering its gobiidea and feeding fish sturgeon caspian sea highest main and the need to fecundity this fish, this study was done in babolroud and tajan rivers in mazandaran. in order to conduct the study, 197 sand goby we were caught using an electros choker machine (v300-200) in the spring of 1390 ,which was the spawning season, at the tajan river (sari) and babolrood (babol). 103 fish whi...

BACKGROUND Native Amazonian populations managed forest resources in numerous ways, often creating oligarchic forests dominated by useful trees. The scale and spatial distribution of forest modification beyond pre-Columbian settlements is still unknown, although recent studies propose that human impact away from rivers was minimal. We tested the hypothesis that past human management of the usefu...

1. Society benefits immeasurably from rivers. Yet over the past century, humans have changed rivers dramatically, threatening river health. As a result, societal well-being is also threatened because goods and services critical to human society are being depleted. 2. `Health' Ð shorthand for good condition (e.g. healthy economy, healthy communities) Ð is grounded in science yet speaks to citize...

Alluvial gully erosion is a likely key sediment source into many large rivers in tropical Australia. This type of gullying differs fundamentally to the generally accepted gully model from Southern Australia, in that it is found exclusively within alluvium and can propagate entirely as a result of basal sapping. The process is found to varying degrees within alluvial river types along most Gulf ...

in this paper, river regime equations through developing of unit stream power equation and based on data of sistan and karaj rivers were derived. at the first step, methods and out-comes of former researchers are classified. on the next step, based on dimensional analysis, unit stream power as a function of river flow parameters including suspended sediment load and specific gravity of particle...

mahi sefid (cyprinidae) is an economically important fish in the south caspian sea. specimens was collected from the lamir river, sefid rud, shir rud and tajan rivers and analyzed at 38 microsatellite dna loci. eight primers out of the thirty analyzed loci were polymorphic in all sampling regions. the highest observed heterozygosity (1) was in locus ca1 in sefid rud and lowest was 0.07 in locus...

s for these talks are published in the GSA Abstracts With

It was found that the build-up of simuliid numbers subsequent to the construction of dams in the Vaal and Orange Rivers could be successfully prevented by periodic, artificially controlled reductions in the water-levels in these rivers.