A Fighting Chance
May - June 2008
We can’t counter all of the changes that have occurred in Great Lakes fish habitat over the past 150 years. But, we can surgically restore some key habitat components and boost critical parts of one of the world’s most important ecosystems.
That’s the logic behind a unique international partnership to build a spawning reef for the threatened lake sturgeon in the lower Detroit River. The Michigan Wildlife Conservancy is joining forces with the U.S. Fish & Wildlife Service, Environment Canada, U.S. Geological Survey, BASF Corporation, the Essex Region Conservation Authority (Canada), and others to construct the rock-based habitat along the shore of Fighting Island in the Detroit River International Wildlife Refuge. The Conservancy’s $30,000 contribution was the first significant private-sector commitment to the project.
“We want to give the lake sturgeon a fighting chance to rebound from over-fishing, water pollution, and loss of spawning grounds that brought the species to the brink of extinction,” says Wildlife Conservancy President David Haywood, of Lansing. “This is an important step in restoring the native fauna of a key part of the Great Lakes.”
The Huron-Erie waterway, which includes Lakes Huron, Erie and St. Clair along with the St. Clair and Detroit Rivers, is an unique connection between Upper and Lower Great Lakes. The Detroit River International Wildlife Refuge alone has 48 miles of what was once some of North America’s most productive shoreline for fish and wildlife. North America’s first International Wildlife Refuge, which is managed by the U.S. Fish and Wildlife Service, is frequented by 30 species of waterfowl, 23 species of raptors, 31 species of shorebirds, 160 species of song birds, and 117 species of fish.
That’s impressive, but still a far cry from what it once was. As late as 1880, the waters teemed with lake sturgeon. But commercial fishermen were harvesting more than 4 million pounds of lake sturgeon annually, and water pollution brought by intensive industrial, commercial and residential development in Michigan’s foremost metropolitan area began to take its toll. Just as damaging to the sturgeon population was sedimentation and direct removal of rocky spawning habitat. Over 8 million cubic yards of gravel were dredged out of the Detroit River in the vicinity of Fighting Island. Not surprisingly, sturgeon nearly disappeared over the next 50 years. While most commercial fishing of sturgeon has been halted, and water quality has improved, the spawning substrate is still lacking.
“The current sturgeon population is about 1 percent of what it was 150 years ago,” explains fish biologist Jim Boase of the U.S. Fish and Wildlife Service. “From 1970 to 1999, there were no documented sturgeon in the Detroit River. But sturgeon are apparently spawning in the Port Huron area and are slowly returning to the traditional spawning areas like Fighting Island in the Lower Detroit River.”
Biologists aren’t sure exactly what the attraction is, but sturgeon are hanging around the historic spawning and nursery grounds. It’s likely a combination of flow, current speed, and a host of other factors that attract the big fish, which are 30-120 pounds when of spawning age.
“There’s something important about the Fighting Island area to sturgeon just like there’s something unique around the Port Huron area where they also congregate,” says Dr. John Hartig, manager of the Detroit River International Wildlife Refuge. “We want to give them a chance to reproduce again by providing what seems to be limiting—a rocky bottom.”
The reef will be made of limestone, fieldstone, gravel, and even coal cinders which have been used as a spawning substrate by sturgeon at Zug Island up-river. The sponsors have raised enough money to construct a 150 by 600 foot reef. Studies of Wisconsin reefs indicate sturgeon seldom use reefs narrower than 50 feet, so size does matter.
“The key to this project is location, location, location,” says Boase. “We can’t restore the 8 million cubic yards of gravel that was here historically, but we can put something back that will help this once-dominant fish population.”
The concept of an international effort to build the reef has been around for about 8 years, and there is now enough support for the project to become a reality. Pre-project population studies involving both the U.S. and Canada have been completed and much useful information about sturgeon movements, population numbers, and genetics has been obtained. Biologists are catching a variety of sizes of sturgeon and finding that the prehistoric-looking fish are reproducing in only a few spots in the Huron-Erie waterway.
Dr. Patrick J. Rusz
Director of Wildlife Programs
Lake Sturgeon Fast Facts
We can’t counter all of the changes that have occurred in Great Lakes fish habitat over the past 150 years. But, we can surgically restore some key habitat components and boost critical parts of one of the world’s most important ecosystems.
That’s the logic behind a unique international partnership to build a spawning reef for the threatened lake sturgeon in the lower Detroit River. The Michigan Wildlife Conservancy is joining forces with the U.S. Fish & Wildlife Service, Environment Canada, U.S. Geological Survey, BASF Corporation, the Essex Region Conservation Authority (Canada), and others to construct the rock-based habitat along the shore of Fighting Island in the Detroit River International Wildlife Refuge. The Conservancy’s $30,000 contribution was the first significant private-sector commitment to the project.
“We want to give the lake sturgeon a fighting chance to rebound from over-fishing, water pollution, and loss of spawning grounds that brought the species to the brink of extinction,” says Wildlife Conservancy President David Haywood, of Lansing. “This is an important step in restoring the native fauna of a key part of the Great Lakes.”
The Huron-Erie waterway, which includes Lakes Huron, Erie and St. Clair along with the St. Clair and Detroit Rivers, is an unique connection between Upper and Lower Great Lakes. The Detroit River International Wildlife Refuge alone has 48 miles of what was once some of North America’s most productive shoreline for fish and wildlife. North America’s first International Wildlife Refuge, which is managed by the U.S. Fish and Wildlife Service, is frequented by 30 species of waterfowl, 23 species of raptors, 31 species of shorebirds, 160 species of song birds, and 117 species of fish.
That’s impressive, but still a far cry from what it once was. As late as 1880, the waters teemed with lake sturgeon. But commercial fishermen were harvesting more than 4 million pounds of lake sturgeon annually, and water pollution brought by intensive industrial, commercial and residential development in Michigan’s foremost metropolitan area began to take its toll. Just as damaging to the sturgeon population was sedimentation and direct removal of rocky spawning habitat. Over 8 million cubic yards of gravel were dredged out of the Detroit River in the vicinity of Fighting Island. Not surprisingly, sturgeon nearly disappeared over the next 50 years. While most commercial fishing of sturgeon has been halted, and water quality has improved, the spawning substrate is still lacking.
“The current sturgeon population is about 1 percent of what it was 150 years ago,” explains fish biologist Jim Boase of the U.S. Fish and Wildlife Service. “From 1970 to 1999, there were no documented sturgeon in the Detroit River. But sturgeon are apparently spawning in the Port Huron area and are slowly returning to the traditional spawning areas like Fighting Island in the Lower Detroit River.”
Biologists aren’t sure exactly what the attraction is, but sturgeon are hanging around the historic spawning and nursery grounds. It’s likely a combination of flow, current speed, and a host of other factors that attract the big fish, which are 30-120 pounds when of spawning age.
“There’s something important about the Fighting Island area to sturgeon just like there’s something unique around the Port Huron area where they also congregate,” says Dr. John Hartig, manager of the Detroit River International Wildlife Refuge. “We want to give them a chance to reproduce again by providing what seems to be limiting—a rocky bottom.”
The reef will be made of limestone, fieldstone, gravel, and even coal cinders which have been used as a spawning substrate by sturgeon at Zug Island up-river. The sponsors have raised enough money to construct a 150 by 600 foot reef. Studies of Wisconsin reefs indicate sturgeon seldom use reefs narrower than 50 feet, so size does matter.
“The key to this project is location, location, location,” says Boase. “We can’t restore the 8 million cubic yards of gravel that was here historically, but we can put something back that will help this once-dominant fish population.”
The concept of an international effort to build the reef has been around for about 8 years, and there is now enough support for the project to become a reality. Pre-project population studies involving both the U.S. and Canada have been completed and much useful information about sturgeon movements, population numbers, and genetics has been obtained. Biologists are catching a variety of sizes of sturgeon and finding that the prehistoric-looking fish are reproducing in only a few spots in the Huron-Erie waterway.
Dr. Patrick J. Rusz
Director of Wildlife Programs
Lake Sturgeon Fast Facts
- Once common and widespread, the species dramatically declined around 1900; it now has a limited distribution in the Great Lakes region, and is a threatened species in Michigan waters.
- Inland populations in Michigan are sparse and restricted primarily to the Manistique, Menominee, Sturgeon, and Indian Rivers in the Upper Peninsula, and the Cheboygan River (including Burt, Mullet, and Black Lakes) in the Lower Peninsula. Occasionally, sturgeon show up in other rivers such as the Grand, Muskegon and Saginaw.
- Lake sturgeon spend a lot of their time in waters 20 to 40 feet deep. They spawn in May or June in a variety of depths, typically 6 to 28 feet. While on river spawning grounds, sturgeon often break the surface with porpoise-like jumps. Females lay several hundred thousand eggs at a time.
- Females become sexually mature at 25 years of age, males at 15. Females spawn every 4 to 6 years, and males every other year. Some individual sturgeon have lived 150 years.
- Sturgeon feed on sand or muck bottoms where they suck in bottom organisms including crayfish, snails, and larvae of mayflies and other insects.