How are Round Gobies Effecting Lake Michigan's Ecosystem?

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1.The Big Picture/The Problem
With many different types of invasive species effecting and threating our water and land here in America it is easy to see that one of largest species that is threating Lake Michigan is the Round Goby. This fish is threating the entire ecosystem of Lake Michigan. It was not originally in Lake Michigan, but it was introduced in the the lake in 1990. The goby entered the lake by ballast water stored in boats traveling throught the St. Clair River. After the fish had adapted to the new environment, it started to become more agressive and take over prime spawning grounds that the native fish uses. This invasive fish has been effecting the ecosystem for many years now and is not going to stop ruining the environment until we find a way to stop the spread and reproduction of this fish. Although many people think this fish couldn't do much damage because of its small size and soft structured body, it can actualy do a lot of damage by defending it spawning terrritory and eating food other native species would eat.


2.Location
The round goby came from the ballast water that boats were using in the St. Clair River. These invasive fish are located in all of the the Great Lakes. Among the Great Lakes, the fish have had the second greatest impact here in Lake Michigan after Lake Erie. As you can see the fish are mostly located in areas where there are harbors such as the Port Washington, Milwaukee, and Sheboygan because there are a lot of rocks and mud in the harbor. The goby likes this because they can hide in the rocks. Another benefit to them is they can get a lot of food in the harbor because the water is quite a bit more stagnant compared to the current of water outside the harbor. Along with the food and shelter the fish are provided with prime spawning grounds that native fish would regularly be using.
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3.Impact
Many people think that the Round Goby is the reason for the recent low numbers of yellow perch that are in Lake Michigan, but they are actually incorrect. It is often believed that the goby eats the perch's eggs, but the eggs of the yellow perch are poisoness to the goby for the time being. Right now the biggest impact is that these fish are taking over native fish spawning grounds and eating their source of food. Although the goby doesn't eat perch eggs, they do eat lake trout eggs. This is a huge problem because the lake trout are not reproducing naturally. Right now they are being stocked by organizations like the DNR.



4.Solutions
Here are a few ways to help with this invasive species. The first is to not use this fish as bait because it can spread into many different lakes. The smallmouth bass will eat them as a means of food. Also if a goby is caught in an area that is not marked in the map above it should be kept in alcohol or frozen and taken to a DNR office. From there it will given to a company that will research it further. Since these fish were introduced because of the ballast water in ships, boats are no longer allowed to empty their water into another body of water other than where it came from.



5.Future Outlook
The future outlook for this ecosystem is not good. Although we have had this invasive species here for about twenty years, it has still not fully affected the entire lake. We may be experiencing many problems that we just haven't noticed yet. Another problem is our native fish reproduction. The goby is eating the Lake Trout's eggs which harms its ability to naturally reproduce. 




References
DNR, . (n.d.). Round goby. Retrieved from http://dnr.wi.gov/invasives/fact/goby.htm

Jude, D. (2011, January 27). Round gobies invade north america. Retrieved from http://www.seagrant.umn.edu/ais/gobies_invade

Lamberti, G. (2003, February 28). Aquatic invasive species. Retrieved from http://www.iisgcp.org/research/ais/lamberti.html

Manninen, C. (2003, January 30). Goby in the great lakes region. Retrieved from http://www.great-lakes.net/envt/flora-fauna/invasive/goby.html#top

 
round goby. (2008, January 28). Retrieved from http://www.glsc.usgs.gov/main.php?content=research_invasive_goby&title=Invasive%20Fish0&menu=research_invasive_fish




Pictures

Confirmed round goby sightings. (2006). [Web]. Retrieved from http://nas.er.usgs.gov/taxgroup/fish/maps/round%20goby%20points.jpg

Engbretson, E. (Photographer). Round goby. [Web]. Retrieved from http://www.google.com/imgres?imgurl=http://c.photoshelter.com/img-get/I0000mIvqjCAgS58/s/650/650/Round-Goby-Y-077.jpg&imgrefurl=http://fish.photoshelter.com/image/I0000mIvqjCAgS58&usg=__HcE9VYWk1BC38-0VO7Ife3hgU2w=&h=427&w=650&sz=98&hl=en&start=0&zoom=1&tbnid=_-Fb_H4hTJuXpM:&tbnh=101&tbnw=153&ei=f9zbTbKVBMbs0gHN24XRDw&prev=/search%3Fq%3Dround%2Bgoby%2Beating%26hl%3Den%26safe%3Dactive%26biw%3D1436%26bih%3D713%26gbv%3D2%26tbm%3Disch&itbs=1&iact=hc&vpx=818&vpy=231&dur=453&hovh=182&hovw=277&tx=175&ty=125&sqi=2&page=1&ndsp=28&ved=1t:429,r:11,s:0&biw=1420&bih=713