Investigating the historic rock reefs of Saginaw Bay

Researchers explore potential for future restoration.

Research team member Nick Kalejs collects samples. Photo credit: Jay Beugly

Research team member Nick Kalejs collects samples. Photo credit: Jay Beugly

The recovery of the Saginaw Bay walleye fishery over the past two decades has been hailed as a national success story. According to Michigan State University Extension walleye numbers have increased so dramatically the Michigan Department of Natural Resources (DNR) is currently proposing to liberalize regulations on walleye fishing in the Saginaw River and Saginaw Bay.

While the Saginaw Bay walleye fishery is thriving, it depends heavily on a single tributary for spawning grounds. Historically, the inner Saginaw Bay was home to rock reefs that provided critical spawning habitat for a diverse list of species including walleye, small mouth bass, suckers, lake whitefish, cisco, and lake trout. Historic land use changes increased runoff into the Saginaw River, which over time buried the once productive rock reefs under layers of sediment. Today the great majority of natural fish production in the system comes from the Tittabawasse River. This reliance on river spawning grounds means that any future river habitat changes would significantly impact the walleye fishery.

Restoring the historic reefs in Saginaw Bay could potentially diversify spawning sites and create a more stable and resilient fishery. Sediment levels in the inner Saginaw Bay are low enough today, due to new farming and land management practices, that the timing is right to explore the potential of reef restoration.

A new project brings together several collaborative partners to assess the status of reef spawning habitat in Saginaw Bay, laying the groundwork for possible future reef restoration. Researchers will focus on two remaining reef sites and two potential restoration sites within the inner bay.

Updates on project status and ongoing sampling efforts were provided to the public at the recent 2015 Lake Huron Fisheries Workshops. The workshops held in Oscoda, Cedarville, and Bay City were attended by more than 250 people from 31 different counties.

Members of the research team provided updates on the progress of the Saginaw Bay reef research project. The research team is in the process of conducting baseline assessments of remnant reef habitat and proposed restoration sites. Two rounds of sampling related to these efforts have already been completed. Jay Beugly, a member of the research team, commented, “It’s a rare opportunity to work in systems as large as Saginaw Bay, and we are excited about the progress we have made towards understanding these sites.” The team plans to continue sampling in the fall and spring. Researchers also shared a video of the sampling team in action with workshop attendees.

Next steps for the project will include side scanner and substrate surveying and genetic analyses of walleye and whitefish populations. The research team is also planning a series of public outreach efforts to engage Saginaw Bay residents and anglers in the project.

For more information on the pre-restoration assessment of fish spawning reefs in Saginaw Bay and updates on project status visit the Michigan Sea Grant webpage.

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