Consider the round goby, a much maligned fish species due mainly to their success in colonizing many waterways including the Great Lakes. One might wonder whether more fishermen have cursed the ugly, unappetizing fish when it greedily grabs their bait than have berated the other “useless” invader; common carp, in the few years the goby has been in the Great Lakes compared to common carp that were introduced intentionally across the country by the U.S. Fish Commission in the 1880’s. In all actuality though, there is much to be admired about this quarter-pint-sized interloper!
The first round goby taken in Lake Erie was electroshocked by Dr. Roger Thoma, formerly of the Ohio EPA Surface Water Division, inside the breakwall at the Grand River harbor in 1993. Given the distance of the first sighting of the round goby from the St. Clair River where it first appeared in 1990, the goby may have been in Lake Erie a couple years before 1993.
If you were planning to invade an ecosystem, what skills would you have that would enable you to do so as efficiently as this happy little fish in the picture below? 
One characteristic would be a sound reproductive strategy, and the round goby excels in this area with eggs that are larger than other species of similar size enabling better survival of the young, especially when coupled with the strong parental care exhibited by the round goby. The male tends the nest, cleaning and guarding it from predators. Round gobies are known to be highly aggressive, invading the most suitable territories for their nests and predations, as well as waiting rapaciously for much larger black basses to leave their nests even for a moment to grab a morsel to eat at which point the pugnacious goby rushes in to gobble up eggs and larvae.
So, is the only good round goby a dead round goby? Not in the strictest sense, if you’re a Great Lakes water snake, or a cormorant (that also prey on and have benefitted from the “explosion” of the water snake population), or even a bass. See, those are all just a few of the many animals that have benefitted from the abundance of round gobies.
