Effects of flood control reservoir habitat conditions and water quality on juvenile muskellunge post-stocking behavior, stress, and growth rate potential

Flood control reservoirs can be challenging for juvenile Muskellunge Esox masquinongy survival and growth because of lack of structurally complex habitat and poor water quality. However, Muskellunge are commonly stocked in reservoirs because of their popularity among anglers, despite often low stocking success. The lack of information on juvenile Muskellunge post-stocking behavior hinders the ability to make stocking recommendations. I undertook three investigations that quantified (1) the potential importance of elevated pH typical of hypereutrophic reservoirs as a stressor and cause of initial post-release mortality, (2) seasonal and spatial changes in growth rate potential (GRP) based on variation in prey density, water temperature, and dissolved oxygen within a large flood-control reservoir, and (3) patterns of survival, space use, and habitat conditions experienced by juvenile Muskellunge released into a large flood control reservoir. In the first study, I found that while stocking Muskellunge into high pH water did not cause initial mortality, fish released into water with a pH of 9.8 experienced behavioral and physiological stress, through ion imbalances and increased surfacing behavior, with signs of recovery four hours after stocking. In the second study, I found that juvenile Muskellunge habitat quality, quantified by GRP, was highest in the summer and riverine zone (i.e., upper reservoir region) and lowest in the winter and lacustrine zone (i.e., lower reservoir adjacent to dam). In the third study, tracking of two different annual cohorts of stocked juvenile Muskellunge showed that there were strong inter-annual differences in post-release survival with 43% survival at the end of the tracking period from the 2019 stocking event and complete mortality five months after stocking in 2020. Movement rate was limited when water temperature was <5 ℃ and increased as water temperature increased through the spring and summer. Stocked Muskellunge initially had low rates of dispersal and limited space use after release (<10 weeks post-release). Distance from release location and maximum spread between individuals increasing over time, until at the end of the study, 6 months post-release, when Muskellunge were distributed across nearly 75% of the reservoir. Dominant habitat types within the daily activity ranges of Muskellunge differed between years. In 2019 when water levels were high (i.e., 4m above summer pool), Muskellunge were primarily associated with emergent and flood terrestrial vegetation. When water levels were lower in 2020 (i.e., 1m below summer pool), Muskellunge used coarse woody habitat and riprap most often. Additionally, here was significantly more structurally complex habitat within Muskellunge activity ranges in 2019 compared to 2020. Together these studies provide insight into how water quality and the spatiotemporal complexity of reservoir habitat conditions, such as water level and prey density, can affect Muskellunge survival, behavior, and growth.

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

• Kramer, Randy J

Contributors dc:contributor

• Parkos, Joseph J
• Porreca, Anthony P
• Suski, Cory
• Ward, Michael

• age-0
• movement
• telemetry
• bioenergetics
• habitat use

Statement dc:rights

• Copyright 2022 Randy Kramer

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/115615

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F115615