Some Effects Of Metals And Detergents On Fishes PDF Download

The River Hayle is located in Mount's Bay District of Cornwall and is an area of high copper and zinc contamination resulting from a long history of mining activity dating as far back as Neolithic times. This study set out to investigate brown trout populations found throughout the river, and to examine the effect that metal contamination can have on fish populations. With metal levels at some parts of the river exceeding environmental quality standards for both copper and zinc the physiological effect that high metal contamination can have on fish was also looked at. This took the form of a series of experiments investigating the affect that copper has on sodium balance as well as its affects on fecundity and general health. Through an electrofishing survey, it was assessed that despite the toxic effects of heavy metals brown trout population still survive in the river. Three species of naive fish (roach Rutilus rutilus, brown trout Salmo trutta and the rainbow trout Oncorhynchus mykiss) were used to examine the direct effect that metal derived from the river has on sodium balance. This was done in order to asses the possibilities of stocking to such contaminated rivers. Using brown trout it was demonstrated that water from Drym (the least contaminated part of the river) had the lowest effect on sodium balance (uptake rate Na ~400nmol g-1 h-1) while the most contaminated site Godolphin had the highest affect (uptake Na -150nmol g-1 h-1). Using these two sites, a comparison was made between the three species. Although this demonstrated that river water has the same affect on sodium uptake in all species with copper inhibiting uptake in Godolphin water. The affect on the two salmonids was greater than the affect on roach, a cyprinid species.