Editors note: Congress is considering a $475 million appropriation for Great Lakes cleanup. This story is part of an occasional look at proposals for spending it. Is this appropriate? Weigh in on this and other ideas on Echo’s Great Lakes Restoration Initiative forum. Other stories.
Efforts are underway to restore Great Lakes sturgeon. Photo: Michigan Sea Grant
By Allison Bush, bushalli@msu.edu
Great Lakes Echo
July 30, 2009
Ugly, huge and primitive – many people wouldn’t think twice about the dwindling numbers of lake sturgeon in the Great Lakes.
But by dumping boulders in Minnesota’s St. Louis River in August, fisheries experts hope to encourage them to reproduce.
The project in the lower part of the river before it empties into Lake Superior is undertaken by the Nature Conservancy of Minnesota and that state’s Department of Natural Resources.
Sturgeon are native to Lake Superior, but their numbers were diminished by overfishing and pollution, said John Lindgren, a fisheries biologist for Minnesota’s DNR.
Officials from the Environmental Protection Agency said that the lake sturgeon population in Michigan is about one percent of its former size. In the 1800s, the Great Lakes basin was one of the most abundant areas for lake sturgeon in North America.
“They were driven to extinction by human impacts, so I think we’re compelled to reestablish those fish populations,” Lindgren said.
The ancient fish is attracting increasing attention. Separately from the St. Louis River project, it could also receive help from the $475 million Congress is considering to restore the Great Lakes.
Under the initiative, an advisory coalition of government agencies has allocated more than $15 million to projects that focus on restoring habitats in the Great Lakes, including those of sturgeon.
The National Oceanic and Atmospheric Administration could receive $300,000 just to study the effects of certain contaminants in sturgeon.
“We’re going to test tissue residue for concentrations of PCBs, and see how it affects the sturgeon’s ability to reproduce,” said Lynne Chaimowitz, technical assistant to the director at NOAA. “This hasn’t been done in a comprehensive regional way so far.”
PCBs are organic compounds that were used to make plastics and as a coolant in transformers. They can harm fish and make them unsafe to eat.
Compared to the millions proposed for other projects in the restoration initiative, $300,000 is a small amount, but it would be enough to get the project started, Chaimowitz said.
“It’s possible it could bring sturgeon numbers back up, but that’s the question we’re trying to answer,” she said.
The researchers will establish the level of contaminants associated with the sturgeon’s ability to reproduce, which can also indicate the health of the environment, Chaimowitz said.
“It’s part of the damage assessment and remediation program,” she said. “We’re going to make sure we do sediment cleanup first in the areas that are identified as more impaired than others.”
But the fish won’t be reproducing unless the right habitat is available.
“The sturgeon are pretty specific in what they look for,” Lindgren said. “They really like focusing on complexes of boulders.”
Overfishing, pollution and dam construction severely decreased the number of lake sturgeon in the Great Lakes in the early 1900s. Agencies began stocking sturgeon fingerlings and fry in the 1980s. More than 850,000 sturgeon were introduced between 1983 and 2001, but there has been no evidence of any reproduction.
However, these fish have matured to the age where they are ready to reproduce, and some have been traveling up the St. Louis River, Lindgren said.
But a series of dams in the river prevents them from traveling further upstream, and the area below the dams is not a suitable habitat for sturgeon to spawn in.
Beginning on Aug. 3, more than a thousand tons of rock will be placed in the St. Louis River, right below the Fond du Lac dam, to create a more inviting place for the sturgeon to reproduce.
The rocks will vary from a couple inches to five feet in diameter and weigh the same as a mid-sized car, said Chris Dunham, forest manager for The Nature Conservancy.
“But it’s beyond just dumping rock in the river — it’s the art of channel manipulation,” he said.
Because lake sturgeon don’t begin reproducing until they are 15 or 20 years old, it might be hard to tell whether the spawning habitat will have a long-lasting effect, said Nancy Auer, associate professor of biological sciences at Michigan Technological University.
There will need to be a focus on preserving the area, because sturgeon imprint, and will remember the area if they have successful reproduction there once, she said.
Although humans might not directly notice the effects that lake sturgeon have on their ecosystem, they feed on dead and dying material in the lakes, and if they are restored to their historic levels, could become an important food source for humans and bears, Auer said.
“Every ecosystem that’s evolved has evolved with a group of organisms that have adapted to specific roles and niches,” she said. “So when we deplete one of those organisms, we throw the entire ecosystem out of whack.”