The effect of hypolimnion reservoir releases on fish distribution and species diversity
releases, fish distribution, survey, water quality
Journal or Book Title
Transactions of the American Fisheries Society
The fish faunas above and below Canyon Reservoir, Comal County, Texas, weresurveyed to determine the effect of the impoundment upon the downstream community. Although22 species were found above the reservoir, only 18 species were taken in the area downstreamfrom the dam. Comparisons with pre-impoundment surveys of this area, taken a quarter centuryago, indicate that seven species, which were once present in the downstream area, are nowabsent. Species diversity indices demonstrate reduced diversity below the impoundment.Changes in downstream water quality, especially water temperatures, due to hypolimnion waterreleases, seem to be the most likely causal factors associated with this disruption of the naturalstream community.