Publication Date

5-1-2008

Degree Program

Department of Biology

Degree Type

Master of Science in Biology

Abstract

The impoundment of flowing waters can cause decreased variation in flow and temperature, reduce habitat availability, and decreased mean temperature below a reservoir. These types of alterations can influence fish communities. Twelve sites were sampled along the Upper Green river in order to address the potential influence of impoundment on fish communities below the Green River Lake. The habitat features: mean depth, flow, dominant substrate, embeddedness, percent riffle, run and pool were measured. Temperature probes were placed at each site in order to measure temperature over an extended period of time. Backpack electrofishing and seining was used to obtain fishes. The lowest richness and Shannon diversity were from the two most upstream sites. Principal components analysis of the wadeable fish data suggests possible differences in species composition at the two most upstream sites when compared to the other downstream sites. Mean daily temperature was significantly different between sites (p = 0.05). Significant differences in seasonal daily means, minimums and maximum temperatures suggests that there are three thermal sections along the Green River within the study area: (1) a cooler section influenced by release patterns from the Green River Dam, (2) a warmer section downstream of the Green River Dam receiving surface inputs from the non-karst tributaries, and (3) the cooler section flowing through the well-developed karst region. Linear regressions only showed significant relationships betwen Etheostoma helium abundances and mean daily temperature (p = 0.002), between Campostoma oligolepis abundances and mean daily temperature (p = 0.043) and between Etheostoma zonale and % gravel. Finding only four significant linear relationship between species abundances and environmental variable suggest other environmental variable not measured may be important for determining species composition in the Green River.

Disciplines

Medical Sciences

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