An Exotic Fish in the Great Lakes pg 2 happen when these two species occupy the same space. Current studies are focusing on competition for limited food, shelter and space with special interest in aggressive interactions. New work will be starting soon to see if these interactions change in low light conditions, as both species are generally more active at night. Many of the areas with round goby populations are best described as infested. Once round gobies arrive they can become the dominant fish species.
Round gobies prefer rocky, shallow areas, but have flourished in a variety of habitat types.
Regardless of the habitat, round gobies are very aggressive fish that compete with native fishes for food and space. Anglers who fish in areas with round gobies often find that the gobies steal their bait and appear to be the only type of fish in the area. Round gobies spawn from April-September with females visiting multiple nests to spawn with several different males. Round gobies attach their eggs to the underside of rocks, in pieces of pipe, or in other types of shelter. Male round gobies stay in the nest to provide care for the developing young and will ferociously defend their nests from any intruders.