Aquaculture and Fisheries Commons^™

A Trophic Gradient Analysis Of Lake Powell: The 1994 Utah State University Aquatic Ecology Laboratory Analyses, Wayne A. Wurtsbaugh, Megan Barker, Ron Brunson, David Fogle, Scott Hawxhurst, Chad Mellison, Lis Phillips, Felipe Queiroz, Daniel Zamecnik

Watershed Sciences Faculty Publications

From 9-11 April, 1994, the Aquatic Ecology Laboratory Class (FW462) of Utah State University sampled the upper reaches of Lake Powell to assess if a trophic gradient existed. We °ampled physical and chemical parameters (temperature, oxygen, conductivity, and total phosphorus), phytoplankton chlorophyll a, littoral and pelagic zooplankton biomass and composition, littoral and profundal benthic invertebrates, and fish abundance measured in the littoral zone (gill nets) and the pelagic zone (hydroacoustics). Data was collected along the upper 50 miles of the reservoir between Bullfrog and the Hite marina near the Colorado River inflow.

Our field trip was done just prior to …

Summer Habitat Use Of Littoral-Zone Fishes In Lake Tahoe And The Effects Of Shoreline Structures, D. Beauchamp, E. Byron, Wayne A. Wurtsbaugh

Watershed Sciences Faculty Publications

We used scuba observations to determine summer habitat use and the effects of piers on the littoral-zone fish community in Lake Tahoe, California–Nevada. Habitat complexity declined with depth. Over 50% of the littoral zone less than 2 m deep was composed of complex boulder substrates, but this substrate represented less than 10% of the habitat between 10 and 18 m deep. A severe drought lowered the surface elevation of the lake 2 m and reduced the wetted complex rocky habitat by 20% between the 0- and l0-m isobaths (referenced to the mean lake level of 1,899 m above sea level). …

Habitat Selection By Lacustrine Rainbow Trout Within Gradients Of Temperature, Oxygen, And Food Availability, Chris Luecke, D. Teuscher

Watershed Sciences Faculty Publications

Rainbow trout (Oncorhynchus mykiss [Walbaum]) in Castle Lake, California were concentrated at certain depths during day and evening hours. A fish bioenergetics simulation model based on vertical gradients of temperature, oxygen concentration, and food availability indicated that rainbow trout selected habitats that maximized growth rate. In 1 of the 2 years of study, a strong pattern of diel vertical migration of rainbow trout was evident and was associated with vertical migrations of daphnids in the lake. The simulation model correctly predicted the occurrence and magnitude of fish migration. During the day some trout resided at depths with little potential for …