This week, a new fish spawning reef was completed in the St. Clair River â€” the Pointe Aux Chenes reef near Algonac, Michigan. Work will begin on a similar restoration project in East China, Michigan next week â€” the Harts Light reef.
I'm reaching out to you to provide a brief update on the project, including a link to recent photos and contact information for project scientists. The team appreciates all the support it has received from partners, stakeholders, local communities and the media.
The Pointe Aux Chenes and Harts Light reefs provide river-bottom rock structures that will attract spawning fish and protect fish eggs. These projects are part of a long-term effort to restore native species such as lake sturgeon, walleye and lake whitefish and remediate the St. Clair River Area of Concern.
About the Reefs
The crevice-filled rock beds are designed to mimic the natural limestone reefs that existed before the rivers connecting lakes Huron and Erie were dredged and blasted to create shipping canals, and before an increased flow of sediments into the system from agricultural and urban runoff.
Both sets of reefs will be located in 30- to 50-foot waters and will not interfere with personal boats or freighters and will have no detectable effect on water flow or water levels. The recently completed Pointe Aux Chenes reef is 1.5 acres: 605 feet long, 108 feet wide and 2 feet tall, and is located between Algonac and Russell Island.
Construction of the Harts Light reef is scheduled to begin next week and is expected to last eight to 12 weeks. The site is adjacent to East China, between St. Clair and Marine City, close to the St. John River District Hospital. The Harts Light reef will be 3.8 acres: 1,007 feet long, 165 feet wide and 2 feet tall.
The $3.5 million project is funded by the federal Great Lakes Restoration Initiative and is a follow-up to fish spawning reefs built in the Detroit and St. Clair rivers in 2004, 2008 and 2012. The habitat-restoration projects are led by a diverse team of scientists that are part of the St. Clair - Detroit River System Initiative.
Characteristics of a Successful Spawning Reef
Over the years, the team has experimented with rocks of different type, shape and size. The latest spawning reefs are being created using broken limestone blocks that are 4 to 8 inches in diameter. That size seems to entice native fish, while discouraging invasive species such as the sea lamprey and round goby. The limestone is from quarries in Michigan and a crane with a GPS-guided clamshell shovel precisely position the rock on the river bottom. The work is being done by Faust Corp., a marine construction firm, along with SmithGroup JJR engineers and architects.
Location of the reef within the river channel is very important. Deep, swift-flowing waters seem to work best, tempting the target fish species while keeping the rocks free of silt, algae and mussels. Also, the rocks must be piled deep enough to form crevices that protect fish eggs from being washed downstream or consumed by predator fish.
Taken together, the Detroit River and St. Clair River reef-building projects represent the largest effort to date to restore a primitive, wild fish within a major urban area in the Great Lakes region. Project scientists will carefully evaluate the impact of these projects on fish populations over the next couple years. Researchers will survey local fish communities and collect eggs deposited on the reefs and fish larvae that emerge from those eggs.
The projectâ€™s core science team includes members from the University of Michigan (Water Center, Michigan Sea Grant), the U.S. Geological Survey Great Lakes Science Center, the U.S. Fish and Wildlife Service, the Michigan Department of Natural Resources and SmithGroupJJR. The Michigan Wildlife Conservancy and the St. Clair-Detroit River Sturgeon for Tomorrow chapter are also collaborators.
Thank you for your interest and support!
Coastal Research Specialist
Michigan Sea Grant