Great Lakes Invasion Goby and Snakehead Fish Hamilton
Friday November 25 2010
Dozens of foreign species could spread across the Great Lakes in coming years despite policies designed to keep them out, causing significant environmental and economic damage, a federal report says.
The National Center for Environmental Assessment issued the warning in a study released this week. It identified 30 nonnative species that pose a medium or high risk of reaching the lakes and 28 others that already have a foothold and could disperse widely.
Among the fish that scientists fear could cause ecological and environmental damage are the monkey goby, the blueback herring and the tench, also known as the “doctor fish.”
The report described some of the region’s busiest ports as strong potential targets for invaders, including in Canada Toronto, Hamilton up to the st. Lawrence seaway and; Superior, Wis.; Chicago and Milwaukee.
Exotic species are one of the biggest ecological threats to the nation’s largest surface freshwater system. At least 185 are known to have a presence in the Great Lakes, although the report says just 13 have done extensive harm to the aquatic environment and the regional economy.
Perhaps the most notorious are the fish-killing sea lamprey and the zebra mussel, which has clogged intake pipes of power plants, industrial facilities and public water systems, forcing them to spend hundreds of millions on cleanup and repairs.
Roughly two-thirds of the new arrivals since 1960 are believed to have hitched a ride to the lakes inside ballast tanks of cargo ships from overseas ports.
For nearly two decades, U.S. and Canadian agencies have required oceangoing freighters to exchange their fresh ballast water with salty ocean water before entering the Great Lakes system. Both nations also recently have ordered them to rinse empty tanks with seawater in hopes of killing organisms lurking in residual pools on the bottom.
Despite such measures, “it is likely that nonindigenous species will continue to arrive in the Great Lakes,” said the report by the national center, which is part of the Environmental Protection Agency.
Some saltwater-tolerant species may survive ballast water exchange and tank flushing, it said. And aquatic invaders could find other pathways to the lakes — perhaps escaping from fish farms or being released from aquariums.
The report does not predict which species might get through. Instead, it urges government resource managers to monitor waters under their jurisdiction in hopes of spotting attacks in time to choke them off.
“Early detection is crucial,” said Vic Serveiss, a scientist with the National Center for Environmental Assessment and the report’s primary writer.Invasive species
Hugh MacIsaac, a University of Windsor biologist and director of the Canadian Aquatic Invasive Species Network, said he expected very few invaders to reach the Great Lakes in ballast water now that both nations are requiring tank flushing at sea. Flushing and ballast water exchange should kill 99 percent of organisms, he said.
“I would be very surprised if their prediction comes true,” he said, referring to the EPA report’s suggestion that numerous invaders could reach the lakes despite the new ballast rules.
The report reinforces the need for further measures to keep foreign species out, including requiring onboard technology to sterilize ballast tanks, said Jennifer Nalbone, invasive species director for the advocacy group Great Lakes United.
“We are only beginning to invest the tremendous amount of resources needed,” Nalbone said. “We’re being hammered by invasive species and are still woefully behind.”
Snakehead fish are native to China but are imported into the US as aquarium fish as well as food fish. Snakeheads can cause serious problems to native fish populations if they get established in Canadian and US waters.
A snakehead was found recently in a river in Welland canal. Incredibly, it was not identified before it was released back into the Lake! It could be an aquarium pet that got too big and was dumped, or it could have been imported for food and somehow been released into the Lake.
Snakeheads look a lot like bowfins. They feed in similar ways and have teeth. If you catch a snakehead, don’t try to lip it! Do kill it, though, do not release it back into the water.
You should never release any kind of fish into waters it was not caught in. Snakeheads are just one example of the kinds of fish that cause problems. Carp are one of the worst of the imports.
Snakeheads are not considered game fish so there are no limits or seasons on them. They should hit live bait or artificials that look like little minnows since that is their major food.
If you catch a strange looking fish, contact your local Game and Fish Department and have them identify it. Help keep your fishing waters clear of snakeheads and other problem fish.
Cormorants go where fish are most plentiful, The following picture show a cormorant feeding on Goby Fish, if so the lakes are full of Them. The picture above was a Goby caught with a salmon roe bag while trying for Trout.
Reports that a reviled northern snakehead fish was caught in the Welland Canal are false, meaning the Great Lakes are free of fish that can sever human arms with their jaws.
“The fish caught was a bowfin,” said Kevin Hill, a spokesman for the Department of Fisheries and Oceans. “This species is native to the area.”
An angler initially believed a northern snakehead — a much-feared invasive species that is native to Asia — almost broke her fishing rod then jumped on her this past weekend.
The native bowfin, described by anglers as, “mean and ugly” can grow to be 109 centimeters in length, have sharp teeth, strong jaws and often ruin artificial lures. Their reputation has made them unpopular with Ontario anglers.
Despite its reputation, the bowfin is a puppy in comparison to the snakehead.
Doug Worrall Photography