Great Lakes freighters may have to treat ballast water to curb invasive species
Aug 27, 2019 04:52AM
● By Editor
From Wisconsin Watch - August 27, 2019
More than $375 billion in cargo — iron ore, coal, cement, stone, grain and more — has flowed between Great Lakes ports and foreign nations since 1959. That is when Queen Elizabeth and U.S. President Dwight Eisenhower christened the St. Lawrence Seaway, heralding it as an engineering marvel.
But that series of locks, dams and channels connecting the Great Lakes to the Atlantic Ocean also carved a pathway for invasive plants and animals to wreak billions of dollars in ecological damage to the lakes. At least 80 invasive species have arrived in the ballast water that transatlantic ships take in and discharge for balance.
The round goby, which came from the Black and Caspian seas in the 1990s, gobbles up food some native fish depend upon. So do European zebra and quagga mussels, which also damage docks and boats and clog pipes and machinery, costing the Great Lakes region an estimated $500 million each year.
More than 20 years of federal and state efforts to regulate ballast water have slowed the introduction of new species to the Great Lakes, which are located in both the United States and Canada. But those regulations exempt “lakers” — hulking freighters traveling exclusively within the Great Lakes — and researchers say that helps invasive species spread after they arrive.
Lakers can transport up to 70,000 tons of cargo and hold up to 16 million gallons of ballast water, enough to fill more than 24 Olympic-sized swimming pools. These ships use tanks of ballast water to maintain balance, dumping or replacing it as they deliver or take on cargo.
“You would expect these ships to move invasive species, and that’s what our research shows,” said Allegra Cangelosi, a Great Lakes ballast water expert and senior researcher at Penn State University-Behrend.
But industry groups argue researchers have not proved lakers move invasive species, and new regulations would cost hundreds of millions of dollars and grind business to a halt. Lakers handle about half of the $15 billion in cargo that moves around the Great Lakes each year.
For now, no treatment system cost-effectively kills unwanted organisms in laker ballast water, but scientists are racing to find a solution — and test it — before regulators finalize the new rules.
Invasives blanket Great Lakes
Scientists have spent years examining how Great Lakes invaders spread across the region. That work continued on a cold morning in November in Madison, Wis.
Nearly a dozen University of Wisconsin-Madison students and researchers performed a tradition in Lake Mendota, along the northern edge of campus: removing a dock before the lake freezes.
Aside from protecting the dock from ice damage, the effort offered insight into how many invasive zebra mussels occupy the lake. Mike Spear, a doctoral student who watched the action, showed off one wooden piling plucked from the water. Five years ago, it would have looked unremarkably bare. Now, the quarter-inch-sized mussels completely covered it. Spear marveled at the mussels’ persistence in latching onto wood long-ago treated with arsenic.
“You’d think it (arsenic) would prevent colonization,” he said. “These creatures (are) always full of surprises.”
Spear scraped the creatures into a plastic bag. He would later freeze and count the mussels to estimate the density of the species in Lake Mendota. The current guess: “billions,” since a class studying the Madison-area lake first spotted them in 2015.
The mussels had plenty of help reaching the inland lake about 80 miles west of Lake Michigan.
A biologist first spotted the mussels in 1988 in North America while collecting worms in Lake St. Clair, sometimes called “the Sixth Great Lake,” between lakes Erie and Huron. Cargo ships traveling from the Black Sea likely dumped ballast water laden with mussel larvae, according to the federally funded Great Lakes Aquatic Nonindigenous Species Information System — or GLANSIS. Within two years, mussels had spread to all five Great Lakes, likely in ballast water of commercial ships — possibly including lakers — and by attaching to hulls of boats and barges.
Clinging to everything, the mussels can survive days outside the water and gradually reached hundreds of inland lakes by latching onto boats, bait buckets and trailers.
Aside from clogging the pipes of power plants and water systems, invasive mussels out-compete native fish and damage their habitats. In some parts of the Great Lakes, researchers suspect a link between mussel invasions and a decline in whitefish, a lucrative catch for the commercial fishing industry.
Zebra mussels are among 187 nonnative species established in the Great Lakes. They are sometimes called the “poster child” for biological invasions, which the United Nations’ International Maritime Organization calls “one of the greatest threats to the ecological and the economic well being of the planet.”
Their takeover of North American waterways galvanized scientists and policymakers who have sought to thwart their advances in many ways — ranging from the Wisconsin requirement that boaters and anglers inspect and remove invasives from their vessels to treating ballast water of ocean-going ships called “salties,” which have been linked to introductions of 80 unwanted species to the Great Lakes.
But laker ballast water remains unregulated, making it tougher to limit damage from other invaders, researchers say.
“I wouldn’t say every ship movement poses a high risk, but we are sitting ducks for that instance in which a risk arises,” Cangelosi said. “All nature has to do is drop in a bad actor, and we’re sunk.”
To read more of this story and read related reporting, follow this link to the The Bridge website. https://www.bridgemi.com/michigan-environment-watch/battle-looms-over-laws-slow-spread-invasive-spec...
Danielle Kaeding of Wisconsin Public Radio contributed to this story, a collaboration between Bridge Magazine, WPR and Wisconsin Watch. The nonprofit Wisconsin Watch (www.WisconsinWatch.org) collaborates with WPR, Wisconsin Public Television, other news media and the University of Wisconsin-Madison School of Journalism and Mass Communication. All works created, published, posted or disseminated by Wisconsin Watch do not necessarily reflect the views or opinions of UW-Madison or any of its affiliates.