Aquatic Invasive Species of Pennsylvania
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ROUND GOBY

(Neogobius melanostomus)

Round GobyThe round goby is an aggressive feeder that spread quickly throughout the Great Lakes basin. This small, bottom-dwelling fish is even capable of foraging in total darkness!

ORIGIN
The round goby was probably first introduced to the Great Lakes by hitching a ride in the ballast water of ships traveling from its native range in the Ponto-Caspian basin of Eurasia (Eastern Europe and Western Asia).

HABITAT
Gobies are bottom dwelling animals that prefer rocky cobbles in shallow water. They have a voracious appetite and feed on a wide variety of prey including small worms, aquatic insects, fish eggs, fish fry, and zebra mussels; about 70% of their diet is composed of zebra mussels.

IDENTIFICATION
While round gobies can reach 25 cm (10 in) in length, Great Lakes adults are usually less than 18 cm (7 in) long. Female and immature male gobies have mottled gray and brown markings and spawning males turn almost solid black. Round gobies have a soft body with prominent eyes near the top of a round head and a unique single pelvic fin on their ventral side. Their body shape is similar to our native sculpin.

Goby Identification

SPREAD
Once introduced, the round goby population exploded and has expanded rapidly into all the Great Lakes. The round goby has now spread from the Great Lakes into many other waterways, including the Mississippi River.

2002 Distribution of the Round Goby
2010 Distribution of the Round Goby

IMPACT
When round gobies compete with native fish for habitat and spawning sites, they can dramatically reduce native fish populations, particularly bottom-dwelling fish, like mottled sculpin, log perch, and darters. In addition, the goby is a highly prolific breeder that can spawn as many as five times a season from April to September.

PREVENTION AND CONTROL
Round gobies can easily be introduced into new bodies of water as hitchhikers in bait wells, bait buckets, and ballast water. The strongest defense against spreading gobies to new locations is education.

To read more, view the Pennsylvania Sea Grant round goby fact sheet.


FOR MORE INFORMATION ON THE ROUND GOBY

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