the pollution of aquatic ecosystems may affect natural reproduction of fish populations by decreasing the fertilization efficiency. among the various sources of pollution, heavy metals are important group, being found in both freshwater and marine environment. the present study investigated changes of sperm characteristics of caspimyzon wagneri when exposed to manganese (mn). spermatozoids were...

the aim of this investigation was to study macroscopic and microscopic structures of ovaries in barbus grypus of karoon river and their changes during annual maturation cycle. for this purpose, 120 adult  b.grypus with a mean weight of 835.0 to 1012.0 g, were caught from karoon river and transferred alive to the laboratory. after biometrical studies, the weights and morphological appearances of...

We used genetic parentage analysis of 6200 potential parents and 5497 juvenile offspring to evaluate the relative reproductive success of hatchery and natural steelhead (Onchorhynchus mykiss) when spawning in the wild between 2008 and 2011 in the Wenatchee River, Washington. Hatchery fish originating from two prior generation hatchery parents had <20% of the reproductive success of natural orig...

background: fluoxetine (prozactm) is one of the most popular antidepressant that can be released to aquatic systems via sewage-treatment effluents. it is suspected to provoke substantial effects in the aquatic environment. methods: in spawning tanks, specimens were exposed to concentrations of 0 and 0.54 µgl-1 fluoxetine from male introduction until the larvae had hatched. prior to spawning, ne...