This bottom-dwelling fish is a very aggressive feeder consuming everything from insect larvae and fish eggs to zebra mussels. The fish is fairly small, being only around 9 inches in length at the largest. An easy-to-spot characteristic of this fish is its large bulging eyes and slender body. Being native to the Black and Caspian seas it comes from the same environment as zebra mussels, which explains why the goby consumes them as food. It was accidentally introduced by ships dumping ballast water into the great lakes.
The Round Goby is found all throughout the great lakes and further up the St Lawrence, as far as Quebec City.
Impacts & Control
They reduce the amount of sportfish in the great lakes by consuming their young and also negatively affect species at risk such as the Eastern Sand Darter and the Northern Madtom. The previous outbreaks of botulism in the great lakes can also be linked to the Goby as it consumes infected zebra mussels, then the infected goby is then eaten by birds and the birds and larger fish die-off. The native mink have been seen eating the fish, but not to the extent that is controlling populations. There are also efforts made in early detection of the Goby entering new waterways and this is done via a series of underwater cameras.