Lake Superior struggles to remain free of pollutants

Lake Superior is recovering well from "legacy" pollutants such as DDT, but faces new threats from shoreline development that have harmed fish habitat and introduced new chemicals, scientists said this morning at a major conference.

By Larry Oakes, Star Tribune

Last update: October 29, 2007 - 12:16 PM

DULUTH, Minn. -- Lake Superior is recovering well from "legacy" pollutants such as DDT, but faces new threats from shoreline development that have harmed fish habitat and introduced new chemicals, scientists said this morning at a major conference.

More than 400 scientists, teachers and natural resource managers are in Duluth this week for "Making a Great Lake Superior," a conference designed to clarify the issues and strategies for maintaining the health of the world's largest lake.

Governor Tim Pawlenty and polar explorer Will Steger are scheduled to speak this afternoon.

The two said over the weekend that Pawlenty may join Steger next spring for part of his trip to the Canadian Arctic to see first-hand evidence of global climate changes.

Superior "is still the cleanest of the Great Lakes," said Deborah Swackhamer interim director of the U of M's Institute on the Environment. However, she added that near-shore development has increased threats from chemicals that cause endocrine system disruption in fish.

Similarly, logging, mining and development concentrated around rivers that feed the lake have hurt native populations of walleye, sturgeon and coaster brook trout, said Mark Ebener, a biologist with the ChippewaOttawa Resource Authority in Sault Ste. Marie.

The good news, Ebener said, is that the deep-water areas of the lake support vibrant populations of lake trout and other species, making Superior a "very healthy" environment for fish overall.

Asked to identify the biggest threat to the lake, Ebener said, "That's easy: Invasive species, and one in particular."

"The original invasive species -- 'us' -- we are still the worst enemy of the (lake's) aquatic environment."