Date Approved
4-13-2024
Graduate Degree Type
Thesis
Degree Name
Biology (M.S.)
Degree Program
Biology
First Advisor
Eric Snyder
Second Advisor
Marty Holtgren
Third Advisor
Sean Woznicki
Academic Year
2023/2024
Abstract
Lake sturgeon (Acipenser fulvescens) are a state-threatened species in Michigan and have become a focus for conservation. The lower Grand River is home to a remnant population of lake sturgeon between the 6th Street dam in downtown Grand Rapids and Lake Michigan. There has been limited research on age-0 lake sturgeon habitat use in low-gradient and more turbid rivers. To address this deficit, we developed a Habitat Suitability Index (HSI) for age-0 lake sturgeon based on prior literature in the Great Lakes. A HSI combines parameters representing in-stream habitat characteristics to score habitat suitability on a scale of 0-1, 0 being poor and 1 being suitable. Parameters important to age-0 lake sturgeon include, but are not limited to, depth, velocity and substrate. To test Index predictions, and obtain evidence of natural reproduction in the river, we conducted fall nighttime visual surveys to locate and capture age-0 lake sturgeon. All captured age-0 lake sturgeon were measured for total length, implanted with a passive integrated transponder (PIT), and a fin clip was taken for genetic analysis. Sites for visual surveying were selected based on visibility (e.g., relatively shallow) and matched known habitat preferences for age-0 lake sturgeon. Twenty-one age-0+ and one age-1+ were captured in the fall of 2022 and 2023, documenting for the first time that lake sturgeon successfully reproduce in the Lower Grand River. The HSI data rates 6.8% of the lower Grand River as suitable age-0 lake sturgeon habitat. All pre-determined visual sites contained regions of suitable habitat. With the small predicted quantity of suitable habitat, it’s believed that substrate is a limiting factor for age-0 sturgeon in the lower Grand River. Future conservation efforts should be focused on rebuilding and maintaining riparian zones and bank stability to encourage natural bed scouring and to avoid additional input of fine sediments. Telemetry tracking of age-0 lake sturgeon in the lower Grand River is also suggested for future research to determine new areas and habitat zones frequented by lake sturgeon.
ScholarWorks Citation
Gunnett, Benjamin D., "Habitat suitability for age-0 lake sturgeon in the Grand River" (2024). Masters Theses. 1119.
https://scholarworks.gvsu.edu/theses/1119
