Somewhere in Lake Superior there's a sturgeon that should be smiling.
Crews this week are stockpiling 400 truckloads of boulders that later this year will be poured into the St. Louis River just below the Fond du Lac dam in hopes lake sturgeon will use the area for spawning beds.
It's an effort by the Nature Conservancy and the Minnesota Department of Natural Resources to kick-start sturgeon spawning as the prehistoric fish continues its comeback in the St. Louis River and western Lake Superior.
"We think they're already doing it. But they don't have very many good places to do it," said John Lindgren, Duluth-area fisheries specialist for the Minnesota Department of Natural Resources.
Sturgeon were wiped out of the St. Louis River and Lake Superior watershed by the mid 1900s, the victim of overfishing, massive logging runs down the river, habitat destruction and terribly polluted water.
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But better treatment of municipal and industrial sewage cleaned up the water starting in the 1980s. And nearly 150,000 sturgeon from Wisconsin hatcheries were stocked since 1983 to support their comeback.
Some of those fish have grown to nearly 5 feet long, and the sturgeon is starting to reclaim its niche in the St. Louis River estuary.
Now, the last element needed for the return of the lake sturgeon is successful spawning.
Sturgeon can live to be 100 years old and grow to more than 100 pounds. But it takes female sturgeon about 25 years to reach reproductive maturity. Some of the earliest-planted fish should be ready.
For the past two years, Wisconsin and Minnesota DNR officials say they've noticed sturgeon that appear to be spawning. But, so far, there's been no confirmation.
"We haven't officially verified yet. But people are reporting catching fish 12 and 13 inches long, and that would be a 4- or 5-year-old fish. We haven't stocked for eight years," Lindgren said. Any sturgeon caught must be released.
It's hoped improved spawning conditions below the dam -- as far up the river as sturgeon, walleyes and other fish can migrate -- will help. Walleyes also are expected to benefit.
The man-made river channel just below the dam often is too shallow, and the water at times runs too fast for successful spawning. The DNR in August will spread the boulders, about 3 million pounds, to recreate a more natural setting, with deeper water where sturgeon can tuck in behind boulders and deposit their eggs on rubble.
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The Nature Conservancy landed a $50,000 federal grant to move the rocks and the DNR will rework the channel.
"This is going to return the habitat to what it was like before the dam, before the logging runs ... before the river was altered so much," said Daryl Peterson, Northeastern Minnesota field representative for the Nature Conservancy. "Other than the Pigeon River, the St. Louis is really the only river on the Minnesota side of the lake where sturgeon can reproduce very well. So this is a big piece of their return."
