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Full-Text Articles in Aquaculture and Fisheries

A Survey Of Aquatic Invertebrate Communities In Nebraska Sandhill Lakes Reveals Potential Alternative Ecosystem States, J.C. Jolley, E.S. Albin, M.A. Kaemingk, D.W. Willis Jun 2013

A Survey Of Aquatic Invertebrate Communities In Nebraska Sandhill Lakes Reveals Potential Alternative Ecosystem States, J.C. Jolley, E.S. Albin, M.A. Kaemingk, D.W. Willis

Natural Resource Management Faculty Publications

Aquatic invertebrate communities are important to shallow lake ecosystem form and function, providing vital components to the food web and thereby important to achieving lake management goals. We characterized lake invertebrate communities and physicochemical variables in six Nebraska Sandhill lakes and examined these characteristics within an alternative stable state framework. Surveys were conducted during 2005 within each of these lakes by sampling aquatic macroinvertebrate abundance, zooplankton abundance and biomass, phytoplankton biomass, and physicochemical variables. When placed within an alternative stable state framework, the response variables exhibited a gradient of different ecosystem states. Two lakes appeared congruent with the clear water …


Continuous, Pulsed And Disrupted Nutrient Subsidy Effects On Ecosystem Productivity, Stability, And Energy Flow, Michael J. Weber, Michael L. Brown Feb 2013

Continuous, Pulsed And Disrupted Nutrient Subsidy Effects On Ecosystem Productivity, Stability, And Energy Flow, Michael J. Weber, Michael L. Brown

Natural Resource Management Faculty Publications

Resource pulses and subsidies can supply ecosystems with an important source of nutrients that supports additional productivity at multiple trophic levels. Common carp Cyprinus carpio provide ecosystems with a continuous nutrient subsidy through bioturbation and excretion but may also initiate a nutrient pulse through carcass decomposition. We examined how continuous (common carp foraging and excretion), pulsed (carcass decomposition) and disrupted (carp introduced and then removed) nutrient subsidies differed in their ability to alter nutrient availability, ecosystem productivity and stability and energy flow. Nitrogen and phosphorus availability and primary production were highest in pulsed, intermediate in continuous and lowest for disrupted …


Overwinter Mortality Of Sympatric Juvenile Bluegill And Yellow Perch In Mid-Temperate Sandhill Lakes, Nebraska, U.S.A, Jeffrey C. Jolley, Mark A. Kaemingk, David W. Willis, Richard S. Holland Jan 2013

Overwinter Mortality Of Sympatric Juvenile Bluegill And Yellow Perch In Mid-Temperate Sandhill Lakes, Nebraska, U.S.A, Jeffrey C. Jolley, Mark A. Kaemingk, David W. Willis, Richard S. Holland

Natural Resource Management Faculty Publications

Substantial mortality can occur in age-0 fish populations during their first year of life, especially in winter; this can potentially influence overall recruitment into the adult population. As such, we compared relative abundances between fall and spring catches of sympatric juvenile bluegill Lepomis macrochirus Rafinesque and yellow perch Perca flavescens (Mitchill) to evaluate the magnitude of overwinter mortality across locations (five lakes for two years) and through time (one lake for six years). In addition, we compared both quantile-quantile and increment plots, based on length-frequency histograms from fall- and spring-caught cohorts from 2004 to 2010, to determine if mortality was …