St. Paul, Minn. ? Minnesota already lays claim to a mythical blue creature, Babe the Blue Ox.

Now, it can claim a new and puzzling scientific oddity, one sure to be the buzz at bait shops: the blue perch.

Since December, Minnesota ice anglers have landed at least four yellow perch, a common panfish species, that aren’t yellow at all. These are bright blue with an iridescent glow. Startled anglers who have caught the mysterious fish have been sent scrambling to the Internet or the Department of Natural Resources for answers.

The trail eventually leads them to Dr. Wayne Schaefer, a University of Wisconsin-Washington County professor who has been studying blue-hued walleyes in a remote region of Canada since 2000.

Until this winter, Schaefer hadn’t heard of blue perch in Minnesota. But he believes they share the same color variation as the Ontario blue walleyes. The blue perch are likely albino for yellow pigment – the key color element in their skin – and they have skin mucus containing a newly discovered blue protein.

Two blue perch were caught in Lake Mille Lacs this winter. Another came from Lake Winnibigoshish, and another came from Big Lake in Beltrami County, said Schaefer.

He operates a Web site, www.bluewalleye.com, where anglers are reporting their unusual catches.

Nothing about the blue coloring makes the perch unsafe to eat, nor do they have any contaminants, Schaefer said. The blue coloring isn’t an apparent mutation, either, because their DNA resembles normal yellow-colored walleyes and perch.

“The blue walleyes are coming from the cleanest waters in Canada,” said Schaefer, whose school is in West Bend, Wis. “It’s not because of an environmental toxin, but it could be a response to an environmental change, such as more ultraviolet radiation hitting the Earth.”

Whatever the case, Dick Bassing of Andover was startled when he pulled up a blue perch from Lake Mille Lacs on Dec. 18.

“When I first saw it, the silverish part of it really shown; it was really iridescent,” he said. “But when I got it on the ice, it looked silverish and bluish.” Three weeks later, the son of one of Bassing’s friends, Mitch Stone, caught a slightly smaller but identical blue perch.

“How ironic is that?” marveled Bassing. “Here I catch what is a once-in-a-lifetime fish, and someone else I know catches one, too. It really burst my bubble.”