Article reprinted with permission from Oceanspace, formerly located at http://www.oceanspace.co.uk

Issue 158 Monday 26th July 1999
Goby Fish Invasion of Great Lakes Spreading

TORONTO, July 23. The invader is only about four inches long but it threatens to alter the ecosystem of the Great Lakes and is attracting the sort of attention normally reserved for more dangerous ocean predators.

The capture of a round goby fish in Lake Ontario's Bay of Quinte last week has alarmed Canadian authorities who warned on Friday that the goby, which feeds on the fry and eggs of native Great Lakes fish, has now infiltrated Lake Ontario. "This animal has found a niche very much to its liking," said biologist Ron Dermott of Canada's Department of Fisheries and Oceans. "Currently in most states and provinces it is illegal to have a live goby. So if one catches it, they are to kill it." The "`small, pugnacious," offender, a native of the Black and Caspian seas, arrived in North America nine years ago, likely in the ballast of foreign freighters. The round goby was first detected in the St. Clair River but has since spread to all the Great Lakes and provide the backbone of the continent's river transport system. "As we get into more and more a global economy and global trade, the pathways for these exotics to come into our waters, and have a significant effect, increases," said John Mills, regional director general of Environment Canada.

He said the increasingly aggressive goby is beginning to displace other fish like perch, monopolize the food available to other forage fish, and deny others access to spawning grounds. In addition, goby fish feed on the young or eggs of smallmouth bass, walleye and lake trout nestled in rocky shoals.

Marine authorities in Illinois have erected a low voltage electric barrier at the man-made Chicago Ship Canal to stop the migration of the goby into the Illinois River and down into the Mississippi River but Canadian authorities said that is not an option for natural rivers. The goby fish does have one benefit. The fish feeds heavily on zebra mussels, which clog water intake pipes, but not enough to eliminate that problem species. The goby fish, whose predators include sturgeon, bass or pike, "will chase away a fish twice its size," biologist Dermott added. Strategies that Canada is employing to limit the proliferation of goby fish include educating boaters on the proper inspections of boats. In addition, the Coast Guard and Transport Canada inspect commercial vessels to ensure they transfer bilge and ballast waters properly, displacing gobies before they enter the Great Lakes system.

"On the aquatic side, there are a probably a few dozen non-native species in the Great Lakes basin," said Environment Canada scientist Harvey Shears. "At some point, we've got to try and stop the invasion because we just can't predict how the system's going to respond."