Browsing by Author "Mullen, Jason Alan"

Now showing 1 - 1 of 1

Spatiotemporal variation of fish assemblages in Montana prairie streams
(Montana State University - Bozeman, College of Letters & Science, 2007) Mullen, Jason Alan; Chairperson, Graduate Committee: Christopher S. Guy
Fisheries biologists must be certain that their samples represent true parameters to make sound management decisions. A large-scale effort was conducted in the past decade to sample Montana prairie stream fish assemblages. This effort focused on sampling as many streams as possible, mostly during summer. Longitudinal sampling within drainages and replication of sites across time was minimal. Consequently, the spatiotemporal variation of prairie stream fish assemblages in Montana is not well understood. The objectives of this study were to 1) determine the influence of spatial, temporal, and abiotic variables in structuring prairie stream fish assemblages and 2) determine the survey design that best characterizes prairie stream fish assemblages. To assess spatiotemporal variation, lower, middle, and upper sites were sampled on five tributaries of the Yellowstone River during each season over a two-year period. Spatial position explained the greatest amount of variation (18.5%), followed by proportion of fine substrates (13.9%). Season (i.e., temporal variation) was not significant in explaining the overall variation in the fish assemblage. Fish species were associated with lower, middle, and upper spatial positions and along the fine substrates gradient based on abundance by species.