Michigan organizations and agencies are building nine rock reefs in the Middle Channel of the St. Clair River to bolster native fish spawning and restore habitat. The Middle Channel of the river connecting Lake Huron to Lake St. Clair supports one of the largest remaining populations of sturgeon in the Great Lakes.
Each reef will be about 40 feet wide, 120 feet long and 2 feet high. Made of angled limestone and rounded fieldstone, the reefs are an effort to return the river to a spawning hotspot.
About a century ago, the St. Clair River and the Detroit River – which is between Lake St. Clair and Lake Erie were straightened, widened and deepened for shipping. This harmed the places where fish spawn, as limestone and other rocks were displaced and damaged.
But the prehistoric-looking sturgeon, which can weigh between 30 and 100 pounds, still hang out in this Lake Huron to Erie corridor.
The reefs are made of loose rocks piled up. A gentle slope down either side keeps sediment from accumulating. Fish eggs are protected by the gaps between the rocks. In addition to sturgeon, walleye and whitefish will benefit from the long piles of rocks, said Jennifer Read, the acting director and a research coordinator at Michigan Sea Grant.
The two-year project is funded by $1,040,000 from federal Great Lakes Restoration Initiative grants. And this project may even get the St. Clair River off the dubious Great Lakes Areas of Concern list.
The St. Clair River is on target to be delisted in 2014..
Reef success will be monitored by comparing spawning rates in the Middle Channel to places without the artificial beds. Researchers will see if adult fish are hanging out near the reefs, see how many eggs there are and monitor the health of young fish.