Small-bodied fish response to Environmental Pool Management in Pool 26 of the Mississippi River

Seasonal drawdowns of water levels in the Upper Mississippi River System (UMRS), known as Environmental Pool Management (EPM), have been performed since 1994 to harden sediments in backwater lakes to promote the growth of emergent vegetation within the Pools that would otherwise not have vegetation. I used a 1.0 m2 throw trap to sample small-bodied fishes in emergent vegetation within several backwater habitats where EPM had been successful in hardening sediments and producing vegetation. I also collected a representative taxon of macroinvertebrates that were captured in the throw traps, and measured dissolved oxygen, conductivity, and depth for each sample. I analyzed the frequency of occurrence of fishes and species richness among sampling locations. Western Mosquitofish were the most frequently caught fish across all the backwaters, and Ellis Bay was the location with the highest species richness. I compared fish density across sampling locations and mean vegetation biomass from each location. I found an inverse relationship between vegetation biomass and fish density. This suggests that highly vegetated areas in the shallow, no-flow backwater habitats may not be suitable to many fish species. Additional sampling across different year conditions and Pools within the UMRS should be considered going forward to truly understand how fish are responding to EPM-produced vegetation

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Natural Res & Env Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2022

Author dc:creator

• Weldon, Courtney R.

Contributors dc:contributor

• Chick, John H
• Lamer, James T
• Suski, Cory
• Brawn, Jeffrey

• EPM
• small-bodied fishes
• drawdown
• throw trap

Statement dc:rights

• Copyright 2022 Courtney Weldon

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/116132

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F116132