By Janet Pelley
Editor’s note: Asian Carp and other invasive species will be discussed Oct. 11-14 in Detroit at the 2011 Great Lakes Week. Detroit Public Television is providing ongoing coverage of Great Lakes Week at greatlakesnow.org
Canadian scientists are launching a robotic kayak equipped with echo sounder sensors in the Welland Canal this week to see if invasive fish such as the Asian carp could travel between Lake Ontario and Lake Erie.
Some scientists say it’s only a matter of time before Asian carp arrive in the Great Lakes. They worry that the ravenous fish will out-compete native species for food.
The Chicago Sanitary and Ship Canal, which links the Mississippi River basin to the Great Lakes basin, gets much of the attention as a potential entry point for invading carp. Resource managers have focused prevention efforts there.
But other invasion routes need to be monitored, too, said Becky Cudmore, a senior science adviser with Fisheries and Oceans Canada, a federal agency.
“If we’re just focused on our front door and it sneaks in through our back door, we’re in trouble,” she said.
Tracking risk in the Welland Canal
Many invasive species, such as sea lamprey, have slipped through the Welland Canal, where locks lift ships around Niagara Falls into Lake Erie, said Scott Milne, principal of Milne Technologies in Peterborough, Ontario. That gains them access to the upper Great Lakes from the east, but no one has yet proven that a lunker like the Asian carp would swim through this vulnerable passageway.
Because of heavy ship traffic, scientists aren’t allowed to enter the lock chambers with boats and nets to survey how fish move in the canal, Milne said. His robo-kayak, dubbed the “Waterbug,” is ideal for the job since it is unobtrusive and crewless.
Powered by a 12-volt battery that runs two small motors mounted on either side of the 14 foot hull, the Waterbug can turn on a dime in response to radioed commands from onshore operators.
In real time, the kayak’s echo-sounders send acoustic images to a laptop computer that estimates the size of fish and pinpoints their movements. A fish as large as the Asian carp would produce a unique echo, Milne said.
“The idea is to use the echo sounder to see where fish are in the system, then follow up with a camera that takes acoustic images that show distinctive features such as fins,” he said.
The sensors can even be tuned to track tiny invasive zooplankton.
Milne and his partners at Fisheries and Oceans Canada hope the pilot survey of the canal will help measure the risk of passage by Asian carp and inform officials whether and where barriers are needed. And they’ll keep an eye out for other invaders.
Milne doesn’t expect to find Asian carp this year. But if his team finds common carp in the canal, it raises suspicions that Asian carp are also capable of navigating the locks.
The kayak launched from near St. Catharines, Ontario. will complete the survey by mid to late October. The Waterbug will cruise about 26 miles from Lake Ontario to Lake Erie through lock chambers and intervening waters.
“It’s possible to program the Waterbug to run autonomously for 24 hours surveying a system,” Milne said.
Depending on how the Waterbug performs, it could be used for monitoring the effectiveness of such hurdles as the electric barrier in the Chicago Sanitary and Ship Canal, according to Phil Moy, an invasive species specialist with Wisconsin Sea Grant.
Live fish trade poses eastern carp threat
Cudmore co-authored a 2004 risk assessment that concluded there is a high probability that Asian carp could become established in the southern Great Lakes basin and have a significant impact on the ecosystem.
The most likely route of entry to the Saint Lawrence Seaway and Lake Ontario is through the live fish trade, Cudmore said. Live carp are prized in the Greater Toronto Area where fish markets sold over 100,000 kg of Asian carp, much of it still alive, in 2003.
Unfortunately, people buy fish at the market and then release them.
“Individual Asian carp have been found in a tributary of Lake Ontario and in a fountain in downtown Toronto,” said John Cooper, a spokesperson for the Ontario Ministry of Natural Resources.
In 2005, Ontario banned the possession and sale of live Asian carp. The U.S. ban on transporting live Asian carp across state lines went into effect March 22.
Over the past year, the Ministry of Natural Resources has partnered with the Canadian Border Services to intercept three shipments of live Asian carp. A Canadian judge slapped one importer with a fine of $20,000 for a 6,000 pound shipment of carp and fined a repeat offender $50,000 for a 4,000 pound shipment. The third case is still before the courts.
Imported in the 1960s and 70s to control algae in catfish farms in the southern U.S., Asian carp grow up to 4 feet long and weigh more than 100 pounds. The carp invaded the Mississippi River basin in the early 1990s through accidental and intentional releases, Moy said.
Leaping Asian carp have inflicted broken bones and concussions when they land on boaters, Moy said. The ravenous fish has likely out-competed native filter-feeding species in the Mississippi River ecosystem.
“In some parts of the Mississippi River, nine out of every 10 fish caught are Asian carp,” Cudmore said.