Round Goby  (Neogobius melanostomus)

DESCRIPTION

The Goby (Neogobius melanostomus) is a bottom-dwelling fish that rests on rocks and other substrate. It resembles a sculpin (Cottus bairdi and C. cognatus), also known as muddlers or Miller's thumb.  Adult gobies can grow to 250 mm (10 inches) in length. 

While young gobies are solid slate gray in color, larger individuals are covered by black and brown botches and may have tinted green dorsal fins.  During spawning, goby males take on a nearly solid black appearance.

Round gobies are characterized by large heads, soft bodies, and spineless dorsal fins.  They possess fused pelvic bottom fins, unique features which form a suction disk.  It is this disk that allows the round goby to secure itself to fish and substrate in flowing water. Round gobies have a distinctive large black spot on the front dorsal fin; and sculpins often have a dark spot in the same location. Sculpins can most easily be distinguished from gobies by their separate pelvic fins.

Credit: J.E. Marsden & David J. Jude Source: Round Gobies, Fact Sheet 065, Ohio Sea Grant (Sculpin and Distinctive feature of Round Goby)

Credit: Alpena Fishery Resources Office Source: http://midwest.fws.gov/Alpena/roundgoby.htm

  (Source:  Round Gobies, Fact Sheet 065, Ohio Sea Grant, http://www.sg.ohio-state.edu/PDFS/PUBLICATIONS/FS/FS-065.PDF) 

IMPACTS

The Round Goby is an aggressive bottom dwelling fish.  It builds and actively defends nests laid in rocky crevices.  They are able to spawn up to 5 times during the mating season.  They have a sensitive sensory system and are able to locate prey quickly. They have several negative impacts on human and native ecology: 

Their aggressive nature and ability to become abundant quickly may allow them to out compete some of our native species for food resources and spawning habitat.

They will feed on small native fish, including darters, native fish eggs and fry and lake trout. 

Their aggressive feeding nature will be a nuisance to fishermen who have difficulty catching target sport fish in areas where goby are present

On the contrary, there is a positive aspect of round gobies. 

They eat large quantities of zebra mussel, a highly problematic invader species with an extremely high reproductive capacity. North American laboratory studies have shown that individual gobies can eat as many as 78 zebra mussels a day.

(source from: http://midwest.fws.gov/Alpena/roundgoby.htm; http://www.sg.ohio-state.edu/PDFS/PUBLICATIONS/FS/FS-065.PDF)

First discovered in Lake St. Clair in 1990, presumably introduced via ballast water from transoceanic vessels, the round goby and the tubenose goby have spread to lakes Erie, Michigan and Superior and to many rivers including the Mississippi watershed. Round gobies are thriving in the Great Lakes Basin because they are aggressive, voracious feeders which can forage in total darkness. The round goby takes over prime spawning sites traditionally used by native species, competing with native fish for habitat and changing the balance of the ecosystem.

(SOURCE: 1. Round Gobies Invade North America. Great Lakes Sea Grant Network; 
2. Round Gobies, Fact Sheet 065, Ohio Sea Grant, http://www.sg.ohio-state.edu/PDFS/PUBLICATIONS/FS/FS-065.PDF)

To help control the spread of the round goby, people must first be able to identify them.  Only after being able to identify gobies can citizens report new goby sightings. Captured goby (or suspected goby) samples should be preserved in rubbing alcohol or by freezing.  These samples, along with information on where and when they were obtained, can then be passed on to the appropriate state Sea Grant office, fisheries management agency, or other suitable entity to verify their identification.  This will enable researchers and biologists to track the spread of gobies. 

Several precautionary measures can  also be taken to further help control and slow the spread of gobies.  These include:

Inspecting live bait to ensure that no round gobies are accidentally released into fishing areas;

Discarding live bait on land, and not into the water, to ensure that no exotic aquatic life is introduced into native water bodies; 

Implementing Ballast water exchange laws that restrict and regulate the dumping of ballast water within North American waterways.

INSPECT your boat, trailer and equipment and remove any plants and animals.
DRAIN, on land, all water from the motor, livewell, bilge, and transom well. Some exotics may not be visible to the naked eye.
EMPTY your bait bucket on land. Never release live bait into a waterway, or transfer aquatic animals between waterways. 

AFTER leaving the boat launch

WASH your boat, tackle, trailer, and  other equipment to kill any exotic species not visible at the boat launch. This can be done with 104°F tap water, or a high-pressure sprayer. or
DRY  your equipment for at least five days-some exotics can survive for long periods of time out of water.
LEARN what these organisms look like, and know which waterways are infested. 
REPORT any new infestations to any Sea Grant or your Department of Natural Resources.

Source from Illinois-Indiana Sea Grant publication, IL-IN-SG-98-1, http://www.iiseagrant.org/)

Aquatic Nuisance Species: Algae, Bythotrephes, Gobies: Ohio Sea Grant
    http://www.sg.ohio-state.edu/SEARCH/TOPICS/T-ANS.HTM
Publications from Ohio Sea Grant explore various exotic species. 
FS-065  Round gobies invade North America.

Exotic Species: Minnesota Sea Grant  http://www.seagrant.umn.edu/exotics/
This site provides general information about zebra mussels, ruffe and more, including how to identify these species.
Round Goby ID Card  http://www.seagrant.umn.edu/exotics/gobyid.html

Round Goby Distribution Map (Jan. 2000): the United States Geological Survey (USGS)
    http://nas.er.usgs.gov/fishes/images/goby_map.gif
This map shows the current geographic distribution of Round Goby in Great Lakes.

Tubenose Goby Distribution Map (Nov. 1997): the United States Geological Survey (USGS)
    http://nas.er.usgs.gov/fishes/images/pr_marmo.gif
This map shows the current geographic distribution of Tubenose Goby in Great Lakes.

Round Goby: Ontario Federation of Anglers and Hunters
    http://www.invadingspecies.com/index.cfm?DocID=23&Type=Round_Goby
This site provides brief description of goby and Ontario distribution map.

Exotic Species Online Publications Catalog: Michigan Sea Grant   
    http://www.miseagrant.org/pubs/online.html
Gobies: Cyberfish of the '90s  http://www.miseagrant.org/pubs/on/msg96-702.html
Round Gobies Invade North America   
    http://www.miseagrant.org/pubs/on/msg95-500.html

Aquatic Nuisance Species: United States Fish & Wildlife Service 
    http://www.fws.gov/r3pao/alpena/goby.htm
This site provides good background information on the round goby with useful links to maps and reports.

Round Goby Competes with Native fish (Great Lakes Science Center: USGS) 
    http://www.glsc.nbs.gov/science/impacts/goby.htm
This site explains several impacts of goby on native fish.

Round Goby: Fish of the Great Lakes (Wisconsin Sea Grant)
    http://www.seagrant.wisc.edu/greatlakesfish/framefish.html
This page includes a brief description and information on round goby. 

Grant Lakes Information Network (GLIN): Invasive Species in the Great Lakes Region     
     http://www.great-lakes.net/envt/flora-fauna/invasive/invasive.html
This site includes a comprehensive information on invasive species in the Great Lakes.
Goby    http://www.great-lakes.net/envt/flora-fauna/invasive/goby.html