The Detroit River and the St. Clair River do more than just connect the upper Great Lakes to the lower Great Lakes. While most people know the Detroit River and St. Clair River — referred to collectively as the Huron-Erie Corridor — as major commercial waterways used to support shipping and fishing. But this 32-mile connecting channel has another distinction: until the late 1800s, the corridor was an important spawning ground for lake sturgeon. Its fast-moving waters attracted thousands of the large, primitive fish every spring.
In the following decades, the number of lake sturgeon plummeted due to pollution, over-harvesting and loss of spawning habitat. The current population of lake sturgeon in Michigan is estimated to be about 1 percent of its former abundance. Organizations like Michigan Sea Grant and the U.S. Geological Survey are working to restore lake sturgeon and other native fish habitat in the waters of the Detroit River.
Video Overview of the Issue
This video focuses on the successful Middle Channel fish habitat restoration project and the science and collaboration that made it a success.
- National Science Education Standards, 4th-8th grade
- Michigan Grade Level Content Expectations, 4th-7th grade
- HS-LS2-2 Ecosystems: Interactions, Energy and Dynamics. Use mathematical representations to support and revise explanations based on evidence about factors affecting biodiversity and populations in ecosystems of different scales.
- HS-LS2-7 Ecosystems: Interactions, Energy and Dynamics. Design, evaluate and refine a solution for reducing the impacts of human activities on the environment and biodiversity.
- HS-ESS3-4 Earth and Human Activity. Evaluate or refine a technological solution that reduces impacts of human activities on natural systems.
- HS-ETS1.2 Engineering Design. Design a solution to a complex-real world problem by breaking it down into smaller, more manageable problems that can be solved through engineering.
For alignment, see: NGSS Summary
- Describe the basic needs of fish.
- Describe how humans have changed fish habitat in the Huron-Erie corridor.
- Describe the ecosystem factors in the Huron-Erie corridor that can influence fish populations.
- Design sturgeon habitat in the Huron-Erie corridor.
Lake sturgeon were historically abundant in all of the Great Lakes. They served as an important food source for many Native American tribes. When European settlers arrived in the Huron-Erie Corridor region (the region from the St. Clair River in the north down to the tip of Lake Erie in the south), sturgeon were so numerous during the spring spawning run that they were reportedly capable of capsizing fishing boats.
A brief history of sturgeon in the corridor:
- Nuisance Fish
Early commercial fishermen scorned sturgeon as nuisance fish that destroyed their gill nets. A single thrashing sturgeon could tangle an entire net, reducing opportunities to catch valuable lake whitefish or lake trout. People began to catch and kill sturgeon, burning them in great piles along the river or throwing them away.
- Valuable Fish
By the mid-1800s, people had found profitable uses for sturgeon. They harvested sturgeon for their meat as well as their eggs, which were made into caviar. Because they grow and reproduce so slowly, lake sturgeon were soon over-harvested. Historic lake sturgeon populations in the Huron-Erie Corridor supported a fishery that produced 4 million pounds of sturgeon in 1880.
- Threatened Fish
In addition to commercial fishing, the remaining sturgeon population faced a growing number of threats. For example, newly constructed dams blocked their access to rivers that they would use as spawning habitat. Other spawning locations were destroyed by sedimentation from farming, logging and increased industrial pollution.
These changes, combined with the sturgeon’s slow growth, led to its dramatic decline. The current lake sturgeon population is estimated to be at or below 1 percent of their former abundance throughout the Great Lakes basin.
What You Need to Know about Lake Sturgeon:
Name: Lake sturgeon (Acipenser fulvescens)
Average Size: Can exceed 6 feet long, and weigh in excess of 200 pounds. However, most lake sturgeon caught today weigh between 30-100 pounds and are 3-6 feet in length.
Lifespan: Live longer than any other fish species in Michigan; males average 55 years, females average 80-150 years.
Predators: Humans, loss of habitat.
Habitat: Live near shore in depths of 15-60 feet.
Diet: They have a downward facing sucker mouth, which enables them to feed on small animals such as snails, crustaceans, aquatic insects, mussels and small fish along lake and river bottoms.
Spawning: Sturgeon spawn in late spring in fast-flowing rivers. Females spawn once every four years; males spawn every other year. Females deposit millions of eggs on rocky substrate. Because sturgeon are slow to mature – males mature in 15 years, females mature in 20-25 years – and because they don’t spawn every year, the population has been slow to recover.
The Huron-Erie corridor supports a remnant population of lake sturgeon. Fish caught in the Huron-Erie corridor have been in good or excellent condition and growing, but a lack of suitable spawning habitat appears to be limiting lake sturgeon reproduction. A survey showed that 12 former spawning sites were no longer suitable as habitat for reproduction because of changes along the river bottom (dredging, for example).
As a solution, new underwater reefs are being constructed in order to encourage native fish reproduction, like lake whitefish, walleye and lake sturgeon. Studies before and after construction will allow biologists to evaluate the impact of the work and improve future habitat restoration efforts.
Man-made spawning beds have been constructed in the Detroit River near Belle Isle and Fighting Island — and now have been constructed in the St. Clair River as well. Areas selected for spawning beds had all of the necessary conditions for lake sturgeon spawning such as fast water flow, but did not have sturgeon’s preferred rocky substrate. Researchers used the same materials (limestone rock, cobblestone and coal cinders) for these spawning beds that are used by lake sturgeon in other areas of the Great Lakes.
An ongoing effort to restore the habitat for spawning has resulted in more reefs being built. For example, an acre of rock reefs were constructed in the Middle Channel of the St. Clair River in the spring of 2012 and more were created in 2013 and 2014 in the Detroit River. At least one more reef is planned for the summer of 2015.
Dive In: Additional Information
- Reef Project FAQ (2015)
- Restoring Fish Habitat in the St. Clair and Detroit Rivers (2014)
- Rocks in the River: More About Native Fish Restoration (Feature Story, 2014)
Boosting Native Fish in the St. Clair River (News Release, 2014)
- Middle Channel Reef Project Fact Sheet (2011)
- Below the Surface – Restoring an Urban River, Upwellings, Michigan Sea Grant
- Construction of Shipping Channels in the Detroit River, USGS Report
- Lake Sturgeon Response to a Spawning Reef Constructed in the Detroit River, USGS Abstract
- Belle Isle Fish Habitat Project Fact Sheet (2008)
Project Photos (Flickr sets)
- Designing Habitat for Sturgeon
Summary: Students determine need of sturgeon and, based on those needs, design spawning habitat to help support the recovery effort.
Time: Two 50-minute class periods
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Big Sable Point bathymetry.
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