Great Lakes Article:

Alien species still entering Great Lakes an expert says

Thursday, April 20, 2002

Laws requiring cargo ships to dump their ballast water at sea and not in the Great Lakes have lessened but not ended the threat of invasive plant and animal species.

Allegra Cangelosi, senior policy analyst with the Northeast-Midwest Institute in Washington, D.C., said invasive species may still be slipping into Great Lakes waters from residual ballast water or by hitchhiking on hulls, sea chains and anchors.

Cangelosi, a 1978 Kalamazoo College graduate who spoke here Tuesday and Wednesday, said very fine water filters, potent biocides such as ultraviolet light and other preventive measures are needed to eliminate the threat of another invasion similar to the zebra mussel or the Eurasian ruffe.

The two and several other species have been introduced into the Great Lakes when ocean-going vessels dumped their ballast water in Great Lake ports.

Great Lakes water users spend tens of millions of dollars on zebra-mussel control every year, Cangelosi said, primarily to prevent the mussels from clogging water-intake pipes.

The Aquatic Nuisance Task Force estimates that the zebra mussel alone costs municipalities and industries about $360,000 a year and nuclear power plants $825,000 annually.

Introduced in the late 1980s, zebra mussels have spread to inland lakes and rivers across North America.

Other invading species of fish such as the sea lamprey, ruffe and round goby have reduced the populations of native fish such as lake trout, walleye, yellow perch and catfish, threatening a sport- and commercial-fishing industry that is valued at almost $4.5 billion annually and supports 81,000 jobs, according to the Task Force.

Non-indigenous aquatic nuisance plants, such as purple loosestrife, Eurasian watermilfoil and hydrilla have quickly replaced native plants, they said.

The problem of invasive species is worldwide -- "every coastline that ships visit," Cangelosi said in an interview Wednesday. "It's estimated that San Francisco Bay has a new invader every six weeks."

Once the Great Lakes problem was recognized, Congress worked to protect the world's largest body of fresh water by changing rules governing the dumping of ballast water. Cangelosi said ships must now exchange their original ballast water with ocean water no closer than 200 miles from shore.

Flushing is never complete, however, and residual water can remain, she said.

"I look at treating methods that can be used on shipboard -- filters, UV light and other ways to kill or remove plants and animals from ballast water," she said. "Once we find methods, it's up to ship owners to look at the economics and anatomy of the ships, the ballast setup, and determine the best approach.

"We want a suite of tools for them to choose."