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Invasion strategies
Friday, January 25, 2008
After years of neglect in confronting Great Lakes invaders, the federal government has taken one encouraging step to combat this serious threat to our economy and ecology. Last week, the U.S. Department of Transportation announced new rules that will require all ocean-going vessels to flush their ballast holds with saltwater 200 nautical miles from North American shores.
The measure will help kill non-native species that come into the Great Lakes and other fresh water bodies through ship ballast water. These invaders -- more than 180 species to date, including the pipe-clogging, fish-food scarfing zebra mussel -- pose a major threat to the delicate environmental balance of the lakes. In addition, they cost the region an estimated $5 billion a year for clean-up and other expenses.
Recent studies have shown that ballast tanks may not be the only invasion route into the lakes. Plants and animals can hitch rides on the hulls of ships in a process scientists call hull fouling or biofouling. Studies conflict on how serious a problem this poses. But policy makers should take note and devise strategies to measure and, if necessary, fight biofouling.
The new DOT rules expand existing regulations regarding ballast flushing. The saline bath kills many of the fresh-water organisms carried by ships from other ports into the Great Lakes.
Ships take on ballast water or release it to compensate for changing cargo loads. Those that carry ballast into the Great Lakes are required to flush their holds with ocean water. Those that don't carry ballast into the lakes have, until now, been exempt from that requirement. That left open the possibility that residual plants or animals would wash into our waters when those ships opened their tanks to fill up.
The new DOT regulations require these no-ballast ships -- the bulk of those traveling the lakes -- to cleanse their tanks, too. That represents not just good policy but welcome interest from a federal government reticent to tackle the problem head-on. The Environmental Protection Agency and the U.S. Coast Guard have been slow to enact meaningful proposals. Congress has provided inadequate funding.
Meanwhile, scientists are studying the biofouling threat. Some consider plants and animals clinging to ships' hulls to be a problem as big -- or bigger -- than creatures lurking in ballast tanks. Others believe that assessment to be wildly exaggerated.
More study is needed to determine who's right. Research should be done, too, on the best way to keep organisms from attaching to ship hulls. Some evidence suggests electric current passed through metal hulls may repel invaders. So might certain paints or coatings.
Invaders, inside or outside ships, remain one of the biggest threats to the Great Lakes ecosystem. The peril merits more serious attention than federal agencies or Congress have given thus far. U.S. Rep. Vernon Ehlers, R-Grand Rapids, should continue his persistent fight to better fund the battle, as should every member of the Great Lakes delegation. A powerful, united front is the best way to combat the harmful horde.
©2008 Grand Rapids Press
© 2008 Michigan Live. All Rights Reserved.
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