Why this Work?
Lake sturgeon and other Great Lakes fish seek out rocky areas in fast-flowing currents in order to deposit their eggs during spawning season. However, many of the natural limestone reefs and rocky habitat areas were destroyed in the Detroit and St. Clair Rivers when shipping channels were constructed. Similar spawning areas in tributary rivers were made inaccessible as a result of dams or were damaged by development and sedimentation.
Sturgeon numbers declined dramatically in the early 1900s and their population remains at roughly 1 percent of historical levels. Many scientists believe that the recovery of lake sturgeon is hindered by a lack of accessible, high-quality habitat, including rocky habitat needed to successfully incubate fish eggs. As a result, the remediation plans associated with Area of Concern programs in the St. Clair and Detroit Rivers call for the construction of spawning reefs to compensate for the habitat lost historically and to help rebuild degraded fish populations.
A Team Effort
In 2001, a consortium of partners began working to mitigate for historical habitat losses by creating fish spawning reefs made of rock rubble placed on the river bottom. The team is using an adaptive management process to develop and study each restoration effort so that subsequent projects incorporate lessons learned.
Water Center specialists serve as team facilitators and project coordinators to help integrate the knowledge of diverse team members and ensure that decisions are based on sound science and the group’s collective best judgement. In addition, they manage restoration grant funds and oversee sub-contracts for design, permitting and construction and work closely with Michigan Sea Grant on targeted outreach efforts. Partners from the U.S. Geological Survey, Fish and Wildlife Service and Michigan Department of Natural Resources lead the biological and physical monitoring of projects before and after restoration. Graduate students from the U-M School of Natural Resources and Environment have been conducting supplemental studies about larval and juvenile fish near reef projects. Recently U-M researchers specializing in hydraulic engineering have been developing laboratory and computer simulations of water flow over reefs with different shapes to improve project design.
Between 2004 and 2015, the team has helped developed six reef projects in the U.S. and Canadian waters of the St. Clair and Detroit rivers. There are three current reef projects, all in the Detroit River:
- Upstream Belle: A 4-5 acre spawning reef is being planned for an area upstream of Belle Isle. Reef construction is expected to begin in the summer of 2016. For more info, see: Project FAQ.
- Grass Island: This reef project was built in the fall of 2015, creating 4 acres of rocky spawning habitat. The reef is approximately 3,800 feet from the shoreline of Ecorse and Wyandotte, along the western edge of the Fighting Island Channel in the Detroit River. Sampling in May of 2016 shows that lake sturgeon deposited eggs on the new reef – a great success!
- Fort Wayne: A small test reef was established offshore from the historic Fort Wayne park in the Detroit River in fall of 2015. The test reef will be carefully studied to determine if the site is suitable for larger restoration effort.
Project Period: Multiple grants, beginning in 2003 and continuing through 2017
Funding: Current projects are funded by the Great Lakes Restoration Initiative through the Sustain our Great Lakes Program and the U.S. Geological Survey’s Great Lakes Science Center.
- Jennifer Read, Director and Restoration Project PI, U-M Water Center
- Lynn Vaccaro, Research Specialist and Coordinator for Reef Projects, U-M Water Center
For More Information
Reef project webpage, maintained by Michigan Sea Grant
Project factsheet (PDF)
Science in Action: Lessons Learned from Fish Spawning Habitat Restoration in the St. Clair and Detroit Rivers, PDF report
Return of the gentle giants, video produced by USGS
Recent News Stories
Searching for young lake sturgeon near Detroit-area spawning reefs, UM news, January 2017
Reef projects on Detroit River put a charge in sturgeon's love lives, Detroit Free Press, December 2016.
Fiffeen year partnership restores native fish habitat in the Detroit River, Empowering Michigan, December 2016
Sturgeon restoration update, newsletter story, November 2016
Sturgeon spawning grounds restoration shows promising results, IJC newsletter, July 2016
Putting hydrodynamics research to work for fish, February 2016
A home for lake sturgeon, slide show and newsletter story, November 2015
Building a comeback for the Detroit River, radio story by the Environment Report, October 2015
Efforts are being made to boost native fish in St. Clair River, radio story by Stateside, July 2014