Saginaw River Lake Sturgeon
Project Title
MI DNR Southern Lake Huron Sturgeon Restoration and Sub-Adult Monitoring
Project Code
SRLAS
Project Duration
October 2025 - September 2030
Project Description
This research aims to advance understanding of Lake Sturgeon Acipenser fulvescens movement and habitat use as part of the reintroduction program in the Saginaw River Basin. This will complement the soon-to-be-completed movement study on the fingerling fish after release. This study will target larger and older (1–8-year-old fish) immature fish to understand important habitats in the basin. Results from this study could complement and potentially be comparable to other regional sturgeon studies (e.g., Lake St. Clair, Maumee River, Black River, St. Marys River). Project Goals and Objectives The Lake Sturgeon is a species of conservation concern in the Great Lakes and its tributaries, including the Saginaw River basin. While much research has focused on adult Lake Sturgeon, less is known about the habitat preferences and usage patterns of juvenile and sub-adult stages. These stages are critical for the population's recovery, and understanding their habitat needs is essential for effective conservation strategies. This study aims to examine the habitat use of juvenile and sub-adult Lake Sturgeon in the Saginaw River basin. Objective 1: Characterize individual variation in movement behaviors among juvenile and sub-adult Lake Sturgeon in the Saginaw River basin. 1.1 Identify variation in individual movement strategies (e.g., sedentary, migratory, or intermediate), and evaluate behavioral consistency over time (e.g., “homers” vs. “travelers”). 1.2 Evaluate whether individual movement behavior is associated with fish-specific traits (e.g., total length, initial capture location). 1.3 Quantify the proportion of fish exhibiting different movement strategies and assess transitions between behavioral categories over time. Objective 2: Identify environmental conditions associated with sturgeon detections and evaluate seasonal variation in habitat use. 2.1 Characterize environmental attributes near detection locations using coarse-scale data, including water depth, river discharge (from USGS gages), and water temperature (from receivers or nearby stations). 2.2 Evaluate seasonal trends in habitat use in relation to environmental conditions (e.g., temperature, flow), particularly during key periods of movement or site residency. 2.3 Compare habitat associations among behavioral groups (e.g., resident vs. migratory individuals) to assess differential habitat use patterns. Objective 3: Describe spatial distribution patterns and identify key areas and corridors used by juvenile and sub-adult Lake Sturgeon. 3.1 Map spatial distribution of detections across the receiver array to identify high-use areas and seasonal hotspots. 3.2 Identify key movement corridors and transition zones between the river, tributaries, and Saginaw Bay. 3.3 Assess spatial fidelity and range size among individuals and determine whether specific areas are revisited repeatedly by the same fish. Methodology Study Area: The study will be conducted in the Saginaw River basin, divided into four distinct strata for broad comparisons among reaches. Project team will determine the appropriate spatial approach during project meetings. An example spatial approach might be: • Lower Tittabawassee River, Lower Shiawassee River, and the Upper Saginaw River to the Center Street Bridge in Saginaw. Several launches: Rust Ave, Riverfront Park at Center Road. • Saginaw River from the Center Street Bridge to the Bascule Railroad Bridge. Launch: Rust Ave. • Saginaw River from the Bascule Railroad Bridge to the airport. Launch: Vets Park • Saginaw River from the airport to the mouth of the river. Launches: several, Edson, Bigelow, Smith Fish Capture: Set lines will be employed across the five strata to capture sub-adult lake sturgeon. During pre-project pilot sampling in 2024 lake sturgeon sampled ranged from 433-956 mm TL. The sampling strategy is designed to capture 20 fish across a broad spatial array within the river to reflect potential variation in habitat use and movement patterns. Each fish will be carefully handled to minimize stress and ensure their survival post-capture. Tagging: Captured sturgeon will be outfitted with acoustic tags. SLHMU will be primarily responsible for sampling efforts, performing tag surgeries, and handling the acoustic receiver downloads. The Tanner (Alpena Fisheries Research vessel) will also be equipped with tagging gear to take advantage of incidental catch while sampling Saginaw Bay. The tags with the longest battery life will be used that are appropriate to the tag burden determined by fish size. Any mortalities will be processed for relevant information (sex, contaminants, confirmation of age, etc.). Telemetry and Monitoring: Acoustic telemetry will be used to track the movements of the tagged lake sturgeon. In addition to leveraging the existing GLATOS array in Saginaw Bay, receivers will be deployed in strategic locations across the study area to monitor fish movements over time. Acoustic tags will allow for precise tracking of the fish's habitat use, seasonal movements, and behavior. Data Analysis: Movement data will be analyzed by an experienced practitioner, who will use specialized software to examine the sturgeon’s spatial distribution and habitat use patterns in relation to environmental variables, including differences in movement and habitat use based on where fish were initially tagged. This data will help identify critical habitats and seasonal changes in habitat preference. Environmental Variables: During field sampling, key environmental parameters such as water temperature, depth, flow and velocity in rivers, and substrate type when feasible will be measured at each sampling location. These data will be used to correlate with sturgeon movements and habitat preferences. Engage NOAA-GLERL or USGS staff to incorporate key environmental variables. Expected Outcomes • Identification of seasonal habitat use patterns and critical habitat areas for juvenile and sub-adult lake sturgeon. • Understanding of how environmental variables influence habitat selection during different life stages. • Recommendations for habitat management strategies in the Saginaw River basin to support lake sturgeon recovery.
Investigators
Participating Organizations