Round Goby (Neogobius melanstomus)
Aquatic Invasive Species & Fish Diseases
The round goby is a small bottom-dwelling fish native to Eastern Europe, and is believed to have been transported to the Great Lakes in ballast water from shipping vessels. It has spread rapidly since it was first spotted in Lake St. Clair in 1990, now ranging across all the Great Lakes and spreading inland. The round goby prefers rocky, shallow areas but is able to flourish in a wide range of habitat types and can also tolerate poor water quality.
Round gobies may pose a threat to fish populations and food chains in invaded water bodies. Gobies undergo rapid population growth and out-compete native fish species for food and spawning sites. Round gobies are able to spawn frequently and the males aggressively defend their nests. These characteristics result in relatively high numbers of offspring produced over a short period of time. Round gobies also have very broad diets. They prey on several native fish species, such as darters, sculpins and logperch, as well as the fry and larvae of lake trout and sturgeon. They compete for food sources such as invertebrates with native fish species. These characteristics enable the round goby to completely displace small native species from spawning, shelter, and forage areas and become the dominant species in an area. Populations of mottled sculpin and logperch have seen dramatic declines since the arrival of the round goby to the Great Lakes region. Furthermore, round gobies have been implicated in spreading botulism outbreaks to birds and fish that consume them.
In addition to ecological harm, round gobies can also have negative social and economic impacts. They have become a nuisance to anglers due to their abundance and their habit of stealing bait. They have the potential to negatively impact both recreational and commercial fisheries through their impacts on aquatic food chains. There are also concerns that gobies may bioaccumulate toxins from feeding on zebra mussels, which may be passed down the food chain to species that people consume.
Measuring up to 25cm and bearing resemblance to our native mottled sculpin, distinguishing characteristics of the round goby are its frog-like eyes, the black spot on its dorsal fin, and the fused pelvic fin on its belly. To help slow or restrict their spread, round gobies should not be used as bait, and water and organisms from one lake or watercourse should never be transferred to another.
