Standing Crops of Brook Trout Concurrent with Removal of Rainbow Trout from Selected Streams in Great Smoky Mountains National Park

Abstract

Abstract Stream surveys since the 1930's have shown a decline in the distribution of native brook trout (Salvelinus fontinalis) in Great Smoky Mountains National Park. Exotic rainbow trout (Salmo gairdneri) have been implicated as the major reason for the decline. Assuming that this hypothesis is correct, attempts were made to eradicate exotic trout from selected streams from 1976 to 1979 using backpack electrofishing equipment. Because this was the only sampling method allowed to capture fish, expenditures of field time were analyzed. Based upon the 4 years of work, an average of 0.68 man-days was required to electrofish each 100 m of stream section three times. Population estimates using the Zippin method were found to be low. Re-sampling of one stream during 1978 showed that the brook trout population was underestimated on the first sample by about 25%. Although rainbow trout were not eradicated from any study stream, major reductions in their numbers were observed. Brook trout standing crops increased...