Why Gobies Grow Big Bass

Although I’d heard a lot about gobies, an invasive fish species infesting the Great Lakes, until last week I’d never seen one. I just had no idea what they looked like. Then while smallmouth-bass fishing there, I managed to catch a few. The one in this photo ate a small soft-plastic worm.

Gobies are odd little fish, growing up to 10 inches long but more commonly 3 to 6 inches. They apparently entered the Great Lakes via the discharge of ballast water from one or more freighters and were first discovered here in 1990. They have spread and multiplied like crazy, and now number in the millions or more.

They are one reason the smallmouths in Lakes Ontario and Erie get so big. The smallies I was catching averaged 2 to 3 pounds, but 4-, 5-, and even 6-pounders are relatively common. Gobies are terrific bass food, but the bottom-dwelling, sculpin-like fish get even by eating the eggs and fry of the bass.

Gobies also eat just about anything else they can grab, including invasive zebra mussels. So the plot thickens as one invasive species eats another. Unfortunately, the gobies can only eat smaller mussels. So the larger zebra mussels survive and spawn faster than the gobies can eat them.

Millions and millions of zebra mussels filter-feed in the Great Lakes water, substantially increasing water clarity and thus making the fishing a little more difficult. The gobies, meanwhile, by their abundance, are helping to make the bass bigger.

Where this will all end is anyone’s guess. The invasives are here to stay. There are so many of them–and the Great Lakes are so big–that eliminating the intruders is simply impossible. Maybe we’ll just wind up with a strain of giant bass swimming in water to totally clear they’re impossible to catch….