Where Do Young Lake Sturgeon Go After They Hatch?
A Close Inspection of River Habitat
BY DARIN SIMPKINS, GREEN BAY FWCO
Lake sturgeon are a native species found throughout the Great Lakes and their tributaries. Each spring, adults migrate upstream to spawn in turbulent areas of rapids. Eggs are adhesive and roll onto undersides of rocks and into gravel. After eight to ten days, the young hatch, snuggle into the spaces between gravel, and live off a yolk-sac. When the yolk is depleted, the young begin to drift downstream, mostly at night.
Dams constructed for power or mills became barriers to natural movements of sturgeons worldwide and populations declined. In partnership with Michigan Technological University, Michigan Department of Natural Resources, and the US Fish and Wildlife Service, a team of researchers has been searching for young sturgeon and mapping habitats in sections of the Sturgeon River, Houghton and Baraga Counties, Michigan.
The Sturgeon River is about 70 kilometers (km) or 43 miles in length and is one of few in the Lake Superior drainage that has a self-sustaining population; so conditions must be good for this population to persist. Researchers have been sampling, and returning live, newly drifting sturgeon along sections of the river to determine duration and extent of drift and at the same time sampling for co-occurring prey and mapping bathymetry and substrates type. While sampling for these young sturgeon at night can be difficult, new sonar technologies have allowed us to better describe large portions of the riverbed where young are found.
In spring in 2013, 2014 and 2015 we sampled and released 1316 drifting larvae and mapped six km of river. In 2016, we hope to use what knowledge we gained on the Sturgeon River and transfer it to the Cedar River in the Upper Peninsula of Michigan where lake sturgeon are being re-introduced.
For more information, contact: Dr. Nancy Auer, Professor, Michigan Technological University email@example.com