Invasion of the Aliens
Sixty years ago, anglers on upstate New York lakes began landing some gruesome catches. The prized lake trout they'd haul into their boats carried raw...
Sixty years ago, anglers on upstate New York lakes began landing some gruesome catches. The prized lake trout they'd haul into their boats carried raw circular wounds from the razor-sharp teeth of sea lampreys - sometimes with the eel-like lampreys still clamped to their side.
Sea lampreys began invading the Lake Ontario watershed from the Atlantic Ocean after man-made canals connected the two. In the 1920s, Welland Canal improvements gave the exotic lampreys a path for bypassing Niagara Falls. By the 1950s, the predators had spread throughout the Great Lakes ecosystem, and the trout fishery was collapsing. Since then, U.S. and Canadian wildlife agencies have restocked the trout but still spend $16 million a year to poison or trap lampreys where they spawn in Great Lakes tributaries.
As it turns out, sea lampreys were just part of an early wave of a continuing invasion that's taking an ominous toll in North American waters. The Great Lakes have been beset by 179 alien plants and animals, including zebra mussels that clog power plant and sewage-treatment pipes, gunky weeds that snag canoeists' paddles on inland lakes, and European round goby fish that crowd out native yellow perch and devour their eggs. For a decade, biologists also have been tracking Asian carp that escaped from Southern fish farms a decade ago and worked their way up the Mississippi River to its headwaters. For now, a temporary barrier across the Chicago Sanitary and Ship Canal is all that keeps the giant carp from crossing the hydrological divide and spreading into the Great Lakes drainage.
Fighting invasive species now costs the region $50 billion a year, "but we're not getting rid of anything," says Michigan state Senator Patricia L. Birkholz, who chairs the Council of State Governments' Great Lakes Caucus. In fact, biologists detect another Great Lakes invader on average every six to eight months.
Trying to stem the influx, state legislators are taking on one of the Midwest's most powerful lobbies, the Great Lakes shipping industry. Since 1959, when the St. Lawrence Seaway opened, ocean-going ships have delivered European iron and steel products to Cleveland and Detroit, and picked up Midwestern grain as far west as Duluth, 2,100 miles from the sea at the tip of Lake Superior. Deep in their holds, the vessels sometimes carry life never before found in North America.
When holds are not filled completely with cargo, crews routinely take on ballast to keep ships properly maneuverable. Before vessels move up the St. Lawrence River, U.S. Coast Guard rules require captains to declare either that they're carrying no ballast or that they've discharged ballast at sea and replaced it with ocean saltwater. But biologists say foreign species can still lurk inside the hulls and wind up released into American waters. "There's a lot of scuzzy stuff in the bottom of some ships, and that's where these organisms grow," says Birkholz, who also chairs the Michigan Senate's Natural Resources and Environmental Affairs Committee.
Two-thirds or more of non-native invaders in the Great Lakes over the past 45 years arrived in ballast water. Two years ago, Birkholz authored a state law requiring ships docking at Michigan ports to treat or filter ballast water to get rid of exotic organisms. In August, a federal judge in Detroit dismissed a lawsuit by Great Lakes shipping companies that challenged Michigan's authority to regulate ballast practices on vessels that steam to other states and Canadian provinces. The ruling gave a green light to Minnesota, Wisconsin and Ohio legislators who are working together in the Great Lakes Caucus and the National Caucus of Environmental Legislators to set common ballast standards. In time, they're hoping that Congress will order federal regulators to implement nationwide ballast regulations.
But states can't let their guard down. The Nature Conservancy ranks invasive species - both plants and animals, in the water and on land - among the top threats to the country's natural biological diversity. Earlier this year, Minnesota legislators added $2 million to the budget to intensify recreational boat inspections, fund local noxious-weed-control projects and target exotics including Asian carp, zebra mussels, round gobies and viral hemorrhagic septicemia, a virulent fish-killing pathogen discovered in the Great Lakes just two years ago.
Even as concerns shift to global warming, it's crucial that legislators not lose sight of the widespread and irreparable damage that exotics are causing. "I think of invasive species as a cancer on the environment," University of Minnesota professor Peter W. Sorensen told Midwest legislators in 2005. "They're biological pollution, and we need a serious commitment to control them just as with air and water pollution."
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