Stopping aquatic invaders

A court settlement between a dozen environmental groups and the U.S. Environmental Protection Agency over Great Lakes water quality comes better late than never. The action won't reverse the decades of damage done by invasive aquatic species brought to the lakes by oceangoing commercial vessels, but it could stop more from coming.

Environmentalists have long argued that the EPA's 2008 rules for cleaning ballast tanks on ships violated the 1972 federal Clean Water Act. A litany of advocates filed suit against the federal government. They charged that it wasn't adequately protecting the lakes from the introduction of invasive species.

The organisms often arrive in the ballast tanks of cargo ships and oceangoing vessels, which carry millions of gallons of water from Europe or Asia in the tanks to keep ships upright in rough seas. Without stringent pollution controls to kill the aquatic invaders, ships dumping their ballast into U.S. waters have ravaged local ecosystems.

In the Great Lakes, that practice is believed responsible for invasive species including zebra mussels and round gobies. The EPA's reluctance to impose strict regulations on ballast water has been regarded as a huge stumbling block in the fight against foreign invaders that flourish in the relatively shallow and warm waters of Lake Erie.

But the EPA finally dropped its appeal of the environmentalists' lawsuit in an agreement that requires the agency to impose more stringent regulations in ballast-water dumping by 2013.

The new rules will add another layer of standards to existing international regulations, along with state standards and upcoming controls crafted by the Coast Guard.

The development may be too late to reclaim compromised ecosystems along U.S. shores, but it should provide better protection for the next invasive critters down the pike.