Web Goby

By: Lia, Shaya, Tiffany

Where did it come from?
Round Gobies are fish which ocupy the bottom of the Great Lakes. They made their way to Canada from Central Eurasia by stowing away in the ballast of trans-oceanic cargo ships. They adapted to marine and fresh water.

Where are they currently located?
Round Gobies made their first appearance in the St. Clair River in the US. (Time Line Below:)
Lake St. Clair
In the first 2 km of the upper Detroit River
Duluth-Superior Harbour
Lake Superior (Minnesota)
Lake Michigan (Montrose Harbour)
Lake Erie (Ohio, Ashtabula River)

Where did it invade?
The Round Gobies invade the US and the Southern Great Lakes area. The Round Goby population expands rapidly, so their invasion occured very fast. At present, they continue to move north. The Gobies have recently invaded the Mississippi River drainage, and are expected to expand beyond the Great Lakes.
external image goby_map.gif
How can you prevent the Spread of Round Gobies?
To prevent the spread of Round Gobies, we must be able to identify a Round Goby. For biologists to track the spread of Round Gobies, sightings of the fish are needed. If a Round Goby is seen in or outside sighted areas, you are to preserve the fish either in alcohol or freezing it, or you can contact fisheries management agency or a Sea Grant institute. Sightings can only be confirmed by identification, because other fish can be easily mistaken for a Round Goby.


Humans: www.cs.rochester.edu/.../ vision_people.jpg
Seagulls: www.hep.man.ac.uk/.../ photos/Elba/seagulls.jpg
Game Fish:**www.emeraldcoastsands.com/**
Yellow Perch: http://pond.dnr.cornell.edu
Brown Trout:**pond.dnr.cornell.edu/.../ brown_trout.html**
Round Goby: http://**www.nature.org/.../michigan/misc/art10010.html**
Bottom Dweller Fish: **www.palaeos.com/Paleozoic/ Devonian/Frasnian.htm**
Mussels: www.palaeos.com
Darter Fish: **majikthise.typepad.com/.../ mcdonalds_petit.html**
Small Fish: http://**www.global-b2b-network.com/.../fish_finder.html**
Fish Eggs: http://**www.jupiterimages.com/itemDetail.aspx?itemID**=...
Plankton: www.mindfully.org/Water/2005/Plankton-Vanishing


Round Goby in its native habitat, Caspian Sea, the north of the black sea

Caspian Sea

**geology.com/records/ largest-lake.shtml**
Top Carnivore:
Round Gobies are being actively and commercially hunted down by human beings. They usually being used as the fishing bait to lure other fishes. Human beings stayed on top of the food chain of the Caspian Sea as they hunt down other aquatic animals as well.
Round Gobies are being prey for sturgeon, pike, and pikeperch. These species played an important role in the ecosystem of the Caspian Sea. In the fishery industries of the Caspians Sea, these sport fishes essential to the economy as well.
Ecological Niche:
Round Gobies originally lived in coarse, gravelly inshore areas of the Black Sea, Caspian Sea, and the Sea of Azof and tributaries. They generally inhabit shallow areas of the sea. However during winter, they live in water as deep as 60m.They also has a high skill of adaptation to changes in the environment. They can live in salt and fresh water. They are known to hunt at night. Their aggressive behavior of chasing other species’ breeding ground was not a concern in its native grounds. This might be due to the fact that they have co-existed with the native species of the Caspian sea for a very long time.
Their food source in the Caspian Sea has a lot of varieties. They fed on bivalves (clams and mussels), invertebrates such as insect larvae, Crustaceans, wormsmollusksand vegetation. However being aggressive fish they also eat other fish eggs and small fishes.
Primary Consumers:
In the Caspian Sea, the primary consumers of the Round Goby food chain are Crustaceans, worms, mollusks and larval insects. Their producers are plankton.
Threat to the environment:
They were not known to posses any threat to the species living in the Caspian Sea due to having co-evolved with the native species for a long time and perhaps of the sea's huge area.
They are being extirpated in the Caspian Sea while they are overpopulated in the Great Lake.

Food Web of the Round Goby in the Caspian Sea

Kostel, Ken “ Introduced Species Summary Project Round Goby (Neogobius melanostomus)” Last updated on 24th October,2001. Project of Colombia University. Viewed on the 11th January,2008.
Downs, Warren, Wiland, Laurence, White, Elizabeth a. and Wittman, Stephen “Round Goby Neogobius melanostomus” Last updated on 5th February,2002. Copyright the University of Wisconsin Sea Grant Institute. Viewed on the 11th January,2008.<http://www.seagrant.wisc.edu/greatlakesfish/roundgoby.html>
Myriam Fillion, “The Round Goby Neogobius Melanostomus” Last updated December, 2000. Viewed on the 11th January,2008. <http://biology.mcgill.ca/undergra/c465a/biodiver/2000/round-goby/round-goby.htm>
Compiled by Stepanova T.G., CaspNIRKh, Astrakhan, Russia, Ragimov D.B., Institute of Zoology Azerbaijani AS, Baku, Mitrofanov I.V., Kazakhstan AS Institute of Zoology, Alma-Aty. “Neogobius melanostomus (Pallas, 1814)” <http://www.caspianenvironment.org/biodb/eng/fishes/Neogobius%20melanostomus/main.htm>

Images Reference

- Edited by Shaya Mulcahy
Food Web in Current Environment

Top Carnivore
In the Round Gobies current habitat, the top carnivores include Humans and Birds of prey such as Seagulls. Humans and Birds of Prey both feed on Game Fish (such as small mouth and rock bass) which primarily feed on Round Gobies and other smaller fish. Humans, or Anglers, usually fish for sport fish for either commercial or recreational purposes. Birds of Prey thrive off of sport fish to consume energy which is crucial to any living thing.

Seagulls <http://web.ticino.com/multilingual/seagulls.jpg>.
Seagulls <http://web.ticino.com/multilingual/seagulls.jpg>.

The primary predators of the Round Goby are Game fish/Sports fish (such as small mouth, rock bass, walleyes, yellow perch, Lake Trout and brown trout). A sport fish’s diet, however, may also include small fish and other aquatic organisms (crayfish etc.).

Walleye <http://recycledfish.org/home/images/WalleyeUnderwaterSmaller.jpg>.
Walleye <http://recycledfish.org/home/images/WalleyeUnderwaterSmaller.jpg>.

Ecological Niche (Competitors)
Round Gobies, which mainly feed on zebra mussels, small fish and the eggs of other game fish (particularly Lake Trout), must compete with other bottom-dweller fish (such as sculpins) for their prey. In areas which have been invaded by Round Gobies, the Sculpins population has declined drastically. This can lead one to believe that Round Gobies have been consuming the prey of Sculpins, leaving none to be consumed by them, thus decreasing their population.

Sculpin <http://dwrcdc.nr.utah.gov/rsgis2/images/Photos/cottbair.jpg>.
Sculpin <http://dwrcdc.nr.utah.gov/rsgis2/images/Photos/cottbair.jpg>.

Round Gobies primarily feed on Zebra mussels and are able to eat up to 78 Zebra mussels a day. Round Gobies also prey on Darters (a bottom-dweller fish), small fish, the eggs and fry of Lake Trout and Quagga mussels. Round Gobies share the same prey as the Sculpins. With the Gobies high population they have been a major factor of the declining population of the native Sculpins.

Zebra mussels <http://www.watershedcouncil.org/zebra%20mussel%20cluster%20-%20small.jpg>.
Zebra mussels <http://www.watershedcouncil.org/zebra%20mussel%20cluster%20-%20small.jpg>.

Primary Consumers
In the Round Gobies current habitat, Zebra mussels and Quagga mussels, who feed on plankton, are the primary consumers. Other primary consumers include crustaceans and other plant-eating fish which feed on green plants and algae.

Crayfish <http://www.lbap.org.uk/images/species/crayfish.JPG>.
Crayfish <http://www.lbap.org.uk/images/species/crayfish.JPG>.

Producers found in the Great Lakes include plankton, green plants, algae (phytoplankton). All receive their energy from the sun and with the energy taken from the rays, transform solar energy into organic matter which can be used as food on which they thrive.

Algae <http://www.serc.si.edu/labs/phytoplankton/primer/water_qual_graphics/phyto_malassid.jpg>.
Algae <http://www.serc.si.edu/labs/phytoplankton/primer/water_qual_graphics/phyto_malassid.jpg>.

"Harmful Aquatic Hitchhikers." June 29, 2007. US Fish and Wildlife Service. January 11th 2008.

“State of the Lakes Ecosystem Conference (SOLEC)” January 9, 2008.U.S. Environmental Protection Agency. January 16th 2008.

“Walleye Fish Description.” March 8, 2006. Fishing Online. January 16th 2008.

-- Lia

Food Web of the Round Goby in its Current Habitat

-- Shaya