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Characterizing Lentic Fish Assemblages And Community-Environment Relationships: An Evaluation Of Natural Lakes And Reservoirs In Iowa, Usa, Jesse Robert Fischer Jan 2012

Characterizing Lentic Fish Assemblages And Community-Environment Relationships: An Evaluation Of Natural Lakes And Reservoirs In Iowa, Usa, Jesse Robert Fischer

Graduate Theses and Dissertations

Characterizing fish assemblages in lentic ecosystems is difficult due to high habitat heterogeneity and the diversity of methods available to sample fish. Therefore, multiple sampling methods are almost always necessary for gaining reliable estimates of species richness and for sampling different sizes of a particular species. However, most research on the use of multiple sampling methods has targeted recreationally-important species. As such, little information is available regarding the influence of multiple methods and timing (i.e., temporal variation) on characterization of lentic fish assemblages. We sampled six lakes and impoundments seasonally (i.e., spring, summer, fall) with beach seines, benthic ...


Impacts Of Non-Native Species In A Shallow Lake: A Simulation Modeling Approach For Restoration And Management, Michael Eric Colvin Jan 2012

Impacts Of Non-Native Species In A Shallow Lake: A Simulation Modeling Approach For Restoration And Management, Michael Eric Colvin

Graduate Theses and Dissertations

There is a long use of models in fisheries and ecology. These models have varying assumptions of how underlying processes occur. Chapter 2 found that violating the assumption of continuous fishing could have consequences for managing harvest of fish populations. In particular, as more fish are harvested in a discrete rather than continuous fashion, parameter estimates of biomass dynamics models assuming continuous harvest can be biased. Accounting for discrete harvest using a semi-discrete biomass dynamics model reduced parameter bias and should be used when discrete harvest is occurring.

Extending the exponential semi-discrete biomass dynamics model to an actual population of ...


Status, Distribution, And Habitat Associations Of Topeka Shiners In West-Central Iowa, Bryan David Bakevich Jan 2012

Status, Distribution, And Habitat Associations Of Topeka Shiners In West-Central Iowa, Bryan David Bakevich

Graduate Theses and Dissertations

The distribution of Topeka shiner Notropis topeka has declined across its historic range and was listed as endangered under the Endangered Species Act in 1998. In Iowa, the habitat associations of this imperiled fish are not well understood. Our goals were to understand the current distribution and identify abiotic and biotic factors associated with the occurrence of Topeka shiners in stream and off-channel habitats of west-central Iowa. Fish assemblages and habitat characteristics were sampled in 67 stream and 27 off-channel sites during 2010 - 2011. Topeka shiners were found in 52% off-channel sites, but only 9% of stream sites, supporting the ...