Date of Award

12-1984

Degree Type

Thesis

Degree Name

Master of Science

Major

Wildlife and Fisheries Science

Major Professor

Richard J. Strange

Committee Members

Douglas C. Peterson, David A. Etnier

Abstract

Brook trout (Salevlinus fontinalis) populations have been declining in the southern Appalachians and especially in Tennessee since 1900. To assess the loss of range of this southern trout, various agencies have inventoried most of the major trout streams in Tennessee over the past 10 years. To date, however, these surveys have remained disjunct and in some cases overlapping.

Survey reports and field data of brook trout inventories made from 1974 to 1984 were examined to determine the current distribution in Tennessee. Brook trout currently inhabit 275.6 kilometers in 135 streams found in eight east Tennessee counties. Brook trout occur allopatrically in 195.7 kilometers and sympatrically with rainbow trout (Salmo gairdneri) and in some cases brown trout (Salmo trutta) in another 79.9 kilometers. During the course of the recent surveys, 32 previously undocumented streams were found to have brook trout populations.

Brook trout in Tennessee are generally relegated to the less optimum habitat of small headwater streams above 925 meters elevation. These streams usually have soft water, low fertility, and are slightly acidic. Eighty-five selected brook trout streams had a mean pH value of 6.8 with a range 5.2 to 7.5. The mean percent gradient of the brook trout sections of 80 selected streams was 10.0% with a range of 3.0 to 23.0%. Brook trout collected during the study period from 41 streams had an overall mean total length of 151.5 millimeters, weight of 45.5 grams, and condition factor (k) of 1.12.

Brook trout now occupy an estimated 20 to 30% of their former 1900 range. Habitat degradation from past and present development projects, logging, forest fires, unregulated harvest, and introduction of exotic salmonid species have severely reduced the brook trout to its present range and distribution. Most of the loss probably occurred in the early 1900's, but recent surveys prove that the process is ongoing. Current losses of brook trout populations are attributed mainly to the encroachment of rainbow trout as well as stream degradation. Only 33% of the current brook trout streams are known to have waterfall barriers that restrict upstream movement of rainbow trout.

Data on 213 current, previous, and re-established or renovated brook trout streams are presented in appendix form in this thesis.

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