Effects of peatland drainage on the size and diet of yearling salmon in a humic northern river
published: Mar 23, 2001
ArtNo. ESP141015101005, Price: 29.00 €
In the humic River Nuorittajoki, northern Finland, the recapture rates of stocked yearling salmon, Salmo salar L., were lower in riffles affected by loading from peat mining and forest drainage areas than in the reference riffles receiving a considerably smaller loading. The salmon caught from the affected riffles were also smaller and thinner by the end of the summer than those from the reference riffles. The size was inversely related to the estimated particulate matter load imposed on the area. The salmon at the affected riffles appeared to feed less but there was no difference in the niche width between the two types of riffle. Hydropsyche and Rhyacophila larvae occupied significantly larger proportions of the stomach volume in the reference than in the affected riffles whereas Ephemerella larvae had an opposite trend. These observations suggest changes in the foraging of yearling salmon in riffles affected by increased particulate matter loading from drained peatlands.