Glacial lakes, such as those in the Midwest region
of the United States, are ecologically and economically important, and they
provide a wide range of ecosystem services, such as habitat for wildlife and
fishes, flood control and recreational boating. Glacial lakes often support
locally important sport fisheries, such as largemouth bass <i>Micropterus salmoides</i> and bluegill <i>Lepomis macrochirus</i>,<i> </i>which
are partially dependent on suitable habitat within lakes. Nearshore vegetation
is often removed by lakeshore landowners for perceived aesthetics and boat
access, or by area managers as a form of indirect fisheries management and
invasive species control. The connection between nearshore vegetation and fish
population health, though widely studied is somewhat unclear. In the two
research chapters of this thesis we attempted to further understanding of the
environmental factors that influence vegetation abundance and distribution, how
vegetation abundance and distribution influences fish population abundance and
size structure, and how young-of-year (YOY) largemouth bass utilize habitats
within the nearshore environment. In the first research chapter, we used
structural equation modeling (SEM) and data collected by the Indiana Department
of Natural Resources to quantify the complexity of relationships among catchment
characteristics (e.g., catchment size), lake morphology, water quality,
vegetation abundance and distribution, and fish population abundance and size
structure. Across multiple lakes, lake productivity was more influential in
explaining cross-lake variation of largemouth bass and bluegill proportional
stock density (PSD) and largemouth bass catch per unit effort (CPUE) than
vegetation. This may be a result of the feedback between phytoplankton
production and rooted vegetation production. The models we constructed provide
insights into the complexity of environmental variables that influence
nearshore vegetation and fish populations. In the second research chapter we
used stable isotopes (δ<sup>13</sup> Carbon, δ<sup>15</sup> Nitrogen, δ<sup>18</sup>
Oxygen and δ<sup>2</sup> Hydrogen) to examine the consistency of habitat use
and foraging of YOY largemouth bass within Indiana glacial lakes. We observed
spatial variation in stable isotope ratios of YOY largemouth bass between
habitat types and sites. Additionally, there were significant, positive
relationships between δ<sup>13</sup>C of locally collected potential prey items
and δ<sup>13</sup>C of YOY largemouth bass suggesting localized foraging patterns.
Later in the summer, as young bass grew in size and likely switched to
piscivory, we did not observe similar spatial variation in young bass stable
isotopes or spatial relationships between prey and the young bass suggesting
more homogeneous foraging patterns. Understanding the habitat use patterns of
young bass may allow for more efficient and effective management of the
nearshore environment. Overall, a greater consideration for the complexity of
relationships between nearshore habitat and fish populations may facilitate
more effective management.
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/9945098 |
| Date | 17 October 2019 |
| Creators | Patricia A Nease (7469945) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/Nearshore_habitat_and_land-use_effects_on_trophic_interactions_and_growth_of_largemouth_bass_and_bluegill_in_Indiana_s_glacial_lakes/9945098 |
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