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Salmonine Consumption And Competition For Endemic Prey Fishes In Bear Lake, Utah-Idaho, J. R. Ruzycki, Wayne A. Wurtsbaugh, Chris Luecke Jan 2001

Salmonine Consumption And Competition For Endemic Prey Fishes In Bear Lake, Utah-Idaho, J. R. Ruzycki, Wayne A. Wurtsbaugh, Chris Luecke

Watershed Sciences Faculty Publications

Two principal sport fish—the indigenous Bonneville cutthroat trout Oncorhynchus clarki utah and the introduced lake trout Salvelinus namaycush—are the dominant piscivores in Bear Lake, a 282-km^2 oligotrophic system. These piscivores rely predominantly on four endemic prey fish species that make up a major portion of the unique Bear Lake fish assemblage. We estimated the annual biomass of pelagic and benthic prey fish by using hydroacoustic and trawling techniques. We also estimated the lakewide abundance of piscivores with a multiple mark–recapture survey and used a bioenergetics model to compare the population-level consumption of prey fish with prey fish production. Prey fish …


Experimental Study Of The Transport Of Mixed Sand And Gravel, Peter Wilcock, S. T. Kenworthy, J. C. Crowe Jan 2001

Experimental Study Of The Transport Of Mixed Sand And Gravel, Peter Wilcock, S. T. Kenworthy, J. C. Crowe

Watershed Sciences Faculty Publications

We measured a wide range of transport rates for five different sand/gravel mixtures in a laboratory flume. Each mixture used the same gravel, and sand was added to produce mixtures containing 6, 15, 21, 27, and 34% sand. Control of other variables allows us to isolate the effect of bed sand content on transport. As sand content increases, gravel transport rates increase by orders of magnitude, even though the proportion of gravel in the bed decreases. The increase in gravel transport rate is most rapid over the range of bed sand content between 15 and 27%. The increase in transport …


Effects Of Epilimnetic Versus Metalimnetic Fertilization On The Phytoplankton And Periphyton Of A Mountain Lake With A Deep Chlorophyll Maxima, Wayne A. Wurtsbaugh, H. P. Gross, Phaedra E. Budy, Chris Luecke Jan 2001

Effects Of Epilimnetic Versus Metalimnetic Fertilization On The Phytoplankton And Periphyton Of A Mountain Lake With A Deep Chlorophyll Maxima, Wayne A. Wurtsbaugh, H. P. Gross, Phaedra E. Budy, Chris Luecke

Watershed Sciences Faculty Publications

Nutrients can load directly to either the epilimnion or metalimnion of lakes via either differential inflow depths of tributaries or intentional fertilization of discrete strata. We evaluated the differential effects of epilimnetic versus metalimnetic nutrient loading using 17-m-deep mesocosms that extended into the deep chlorophyll layer of oligotrophic Pettit Lake in the Sawtooth Mountains of Idaho. Addition of nitrogen plus phosphorus stimulated primary production nearly identically (2.4- to 4-fold on different dates) in both treatments, with the production peaks occurring in the strata where nutrients were added. The metalimnetic fertilization, however, resulted in equal or greater stimulation of chlorophyll a …