About 30,000 channel catfish were released into the Chicago and Little Calumet rivers Tuesday as part of a program that officials say shows how far those urban waterways have come environmentally.

"This is exciting because the Chicago River is evolving into a place where these fish can thrive," said Margaret Frisbie, executive director of Friends of the Chicago River. "This project is symbolic of how far the Chicago River has evolved. We can release catfish and know that they will thrive."

Frisbie's group, along with the Illinois Department of Natural Resources, oversaw the release of 10,000 catfish into the Chicago River from Lower Wacker Drive below the 333 W. Wacker building, and 20,000 catfish into the Little Calumet River, which runs south of the city.

The fish release is part of a $300,000 restoration effort, paid for with a grant from the National Fish and Wildlife Foundation Chi-Cal Rivers Fund, to increase the population of catfish in Chicago-area waterways. An additional 20,000 catfish will be released this summer and 50,000 will be released next summer.

"We're trying to improve the river so that it's a healthy habitat for everyone, including for fish," Frisbie said. "Catfish is a good fish to start with because they are familiar, people like to fish for them. They are a fish people have heard of and care about."

Later this summer, officials plan to create 400 nesting cavities in eight locations, three in the Little Calumet and five in the Chicago River, so the fish will be encouraged to reproduce.

The nesting sites will imitate natural objects like logs where the fish plant their eggs, Frisbie said. While Friends of the Chicago River is still designing the cavities, current plans consist of ones made from a combination of open-ended PVC pipes attached to concrete weights.

Channel catfish are native to the region. But they have not been abundant in the Chicago and Little Calumet rivers because of limited habitat and poor water quality, said Marc Miller, director of the Department of Natural Resources, which harvests several types of fish for stocking.

The catfish released Tuesday were about a year old, 5 inches long and not quite ready to reproduce. Officials had some of the gray-green fish in a bowl, their "whiskers" fluttering as they swam back and forth. Fisherman will have to wait a few more years before these fish become fair game.

"Now that we have better water quality, this project is going to bring back a spawning habitat, and we think they're going to thrive here and take hold," Miller said. "And I think that's a positive step for the Chicago River and recreational fishing."

In the 1970s, before efforts to clean up the river began in earnest, there were only about three or four fish species living in the Chicago River. Today there are more than 70, Miller said.

As the department continues to repopulate Chicago's rivers, Miller said he will consult with its biologists about which species are needed. The department surveys fish populations about every five years and will be monitoring the catfish's reproductive progress.

Kathleen Meany, president of the Metropolitan Water Reclamation District of Greater Chicago's board of commissioners, said water quality will continue to improve once the $21 million construction of the Calumet and O'Brien water reclamation plants is complete in December 2015.

"When I came on the board 24 years ago, all the back doors of the buildings facing the river (were) not considered an amenity," Meany said. "Today, you look around, you see hotels, restaurants, walkways (along the river), making it a beautiful, world-class city, and it's beautiful because of the improvements in the water."

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