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Lake Ontario Invasion Begins - "Round Gobies" Feed on Sport Fish Eggs, Zebra Mussels

TORONTO – July 23, 1999-- A foreign invader fish recently arrived in the Great Lakes is expected to start colonising Lake Ontario next year, bringing with it concerns for a $138 million annual sport and commercial fishing industry.

"Unfortunately, eliminating a species after it has become established is usually impossible," said John Mills, Regional Director General of Environment Canada’s Ontario office. "It may be possible, however, to slow their spread. There are many things citizens can and should do to reduce the problem."

The round goby feeds heavily on zebra mussels, consuming up to 78 per day (though gobies are not expected to eliminate that problem species). Gobies are in turn preyed upon by several sport fish species, including smallmouth bass, walleye, sturgeon, yellow perch and brown trout.

"The arrival of the goby into Lake Ontario will bring about changes to the ecosystem," says Ron Dermott, federal fisheries expert on Great Lakes aquatic nuisance species. "This small fish may help curb the numbers of zebra mussels to some extent. However, the goby menaces native fish populations by eating their eggs and offspring, aggressively competing for food, and denying others access to spawning grounds."

Mr. Dermott said the goby "will chase away a fish twice its size. For sport fishermen, it’s a further nuisance because it aggressively steals bait."

In the last two years, gobies have become very common in western and Central Lake Erie; they’re expected to populate the eastern basin this year and one was caught this month in Lake Ontario near Glenora.

The most important strategy to combat the proliferation of gobies and other exotic species is public education.

Before leaving any water body, boaters should:

• Inspect their boat, motor, trailer, and equipment (anchor, centreboards, rollers, axles) and remove any visible plant or animal;
• Drain water from the motor, live well, bilge and transom wells while on land;
• Wash/dry their boat, tackle, down riggers, trailer, and other boating equipment to kill harmful species that were not visible at the boat launch.

Since some aquatic nuisance species can survive more than 2 weeks out of water, it is important for boaters to either:

• Rinse boats and any equipment that normally gets wet with hot tap water (greater than 40 °C); or
• Spray your boat and trailer with high pressure water (250 psi); or
• Dry boats and equipment for at least 5 days before transporting to another water body.

Bait buckets should be emptied on land before leaving any water body. Live bait should never be emptied into a water body. Likewise aquatic animals should never be released from an aquarium or from one water body into another.

Finally, boaters should learn to identify exotic species. Caught gobies should be killed, frozen and reported to the Ontario government’s Invading Species Hotline (1-800-563-7711). American anglers should notify the U.S. Fish and Wildlife Service or their state officials.

10th International Aquatic Nuisance Species and Zebra Mussel Conference, Toronto

The infestation of the Great Lakes by gobies will form an important focus for discussions at the upcoming 10th International Aquatic Nuisance Species and Zebra Mussel Conference February 14 to 18, 2000, in Toronto. Hosted by the Federal Department of Fisheries and Oceans and held at the Westin Harbour Castle, the conference will convene some 400 scientists from North America and around the world to share research results, as well as news of developments in control technologies, public education programs, and other information.

The conference will focus on the problem of exotic aquatic plants and animals in both freshwater and marine environments.

Preventing the introduction of new exotic species has also been identified as a key priority as the federal government plans the next phase of its Great Lakes program, Great Lakes 2000 which expires in March 2000.

"Invasions of exotic species can cause severe damage to both the ecosystem and the economy," Mr. Mills said. "The cost to North Americans of repairing and combating damage by zebra mussels alone to municipal and industrial water intakes is estimated at $5 billion over the past 10 years."

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