Round Goby

  • Round Goby

    (Neogobius melanostomus)

    The Round Goby is a rapidly reproducing invasive fish native to the Black and Caspian seas in eastern Europe. A small, bottom dwelling fish, it was likely introduced to North America through the dumping of ballast water by ships from Europe. It was first observed in the St. Clair River north of Windsor in 1990 and has since spread to all of the Great Lakes and some inland water bodies. Round Gobies spawn multiple times per year and have reached densities of more than 100 per square metre in some areas.

    Preferring water bodies with rocky and sandy bottoms, Round Gobies are voracious feeders that can eat as many as 78 Zebra Mussels per day. In addition, they eat Quagga Mussels, insects and other small organisms found on water bottoms and occasionally small fish and fish eggs. The Round Goby has a well-developed lateral line that detects water movement, which may help it to outcompete native fishes for food in murky water conditions.

    No control methods exist at the present time, but research has been conducted on local control solutions involving fish poisons, pheromone from the urine of male Round Gobies and seismic guns.

    Range

    Round Gobies are found in the Great Lakes and many of its tributaries, as well as some inland water bodies in southern Ontario, including Lake Simcoe, the Trent River, Rice Lake and parts of the Otonabee River.

  • Identification

    • Featuring a cylindrical body and rounded to blunt snout, Round Gobies usually range from 6 to 16 cm in length, with some reaching up to 25 cm.
    • Their fully scaled bodies are brownish to olive in colour with dark brown spots.
    • They have nostril tubes which do not reach the upper lip and frog-like raised eyes.
    • Round Gobies have a single scallop-shaped pelvic fin and a black spot on the dorsal fin, which differentiates them from other species in the Great Lakes. No native species has a single pelvic fin and the invasive Tubenose Goby (Proterorhinus semilunaris) and native Sculpin (Myoxocephalus thompsoni and Cottus sp.) do not have the black spot.

    Impact

    • The Round Goby’s aggressive habits and rapid expansion have seriously impacted a number of native species, including the Mottled Sculpin (Cottus bairdii) and the Logperch (Percina caprodes).
    • The introduction of Round Gobies to the Great Lakes has threatened several species at risk, such as the Northern Madtom (Noturus stigmosus), Eastern Sand Darter (Ammocrypta pellucida) and several species of freshwater mussels.
    • Populations of sport fish have been reduced by the Round Goby’s consumption of eggs and young fish and its competition for food.
    • The Round Goby has also been linked to outbreaks of botulism type E in Great Lakes fish and fish-eating birds.

    How can you help?

    • Learn to identify Round Goby and how to prevent its spread to other water bodies.
    • Do not buy or use Round Gobies as bait; it is against the law. Ontario law also prohibits the possession of live Round Gobies.
    • Do not put any live fish into Ontario’s water bodies.
    • Report any information about the illegal importation, distribution or sale of Round Goby to the toll-free Ministry of Natural Resources TIPS line at 1-877-TIPS-MNR (847-7667) or contact your local Ministry of Natural Resources office (ontario.ca/mnroffices) during regular business hours. You can also call Crime Stoppers anonymously at 1-800-222-TIPS (8477).
    • If you catch or observe a Round Goby or other invasive species, please contact the Turtle Island Invaders hotline at 1-844-872-2348 (1-844-TRACE-IT) toll-free or report the sighting to your local Lands or Natural Resources officer.
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