Fisheries research in Saginaw Bay has taken several forms in past years. Much of it has been focused on understanding the factors affecting walleye and recovery of that population.

Research findings have determined that walleye in Saginaw Bay are a mix of stocked fish, immigrants from outside Saginaw Bay, and Wild (naturally reproduced) fish. Most of the remaining natural reproduction comes from rivers as opposed to reef based spawning which historically was believed to also have been important. Overall, in recent years walleye in Saginaw Bay have been recruitment limited, with that limitation coming from habitat degradation and possibly the effects of the nonnative alewife which can compete and prey upon newly hatched walleye fry.

The habitat loss has stemmed from blockage of spawning rivers by dams and spillways. The best (inner bay) rock reefs have been degraded by years of sedimentation stemming form erosion in the watershed. Stocked walleye survive well in Saginaw Bay but those numbers alone can’t bring the walleye population and fishery back up to historic levels. Needed is improved natural reproduction. A walleye recovery plan was recently developed by the Michigan DNR to build upon years of research findings and formulate strategies to fully recover the walleye population. Included are strategies that involve fish passage/dam removal, stream habitat improvement via sediment reduction, and possibly some reef renovation. Local suppression of the abundant alewife population within the bay is also sought partly by increasing stocking to the extent possible.

At stake is not just a better walleye fishery, but instead is a better ecological balance in Saginaw Bay. Unlike the main basin of Lake Huron, Saginaw Bay has insufficient predators to fully utilize its abundant prey base. Walleye are the keystone predator in the bay’s fish community their full recovery is needed to bring balance to the ecosystem. Expected are benefits for other species including yellow perch.

Progress towards walleye recovery received a big boost in 2003 when annual surveys detected a new record year class or walleye (and yellow perch too). These year classes were upwards of 5 times greater than the previous year classes. Its believed that ideal spring weather conditions and a low abundance of alewives that year led to these very strong year classes. If these year classes continue to survive well, they will a very significant step forward in our walleye recovery goals.

Department of Natural Resources’ research today on Saginaw Bay includes an annual Fish Community Survey that includes sampling across the entire mix of fish species using variable mesh gillnets and bottom trawling. These collection efforts sample nearly the entire fish community providing data with which to assess trends in many different fish populations.

Another project is a Walleye Tagging study that annually affixes metal jaw tags to 3,000 Saginaw Bay walleyes. The fish are collected during their spawning migration in the Tittabawassee River. Tagged and then released again. Anglers reporting the tags forms the data that is then used to understand movement of the fish, exploitation rate, and estimate mortality rate.

These two research projects in combination with the annual creel survey provide a suite of information that enables the DNR to manage the Saginaw Bay fisheries and gauge recovery of walleye.