Invasive species - Marschner 1 Travis Marschner Mustafa...

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Marschner 1 Travis Marschner Mustafa Mazher ISB 208L-034 11/21/09 The Round Goby – A Notorious Assassin BACKGROUND : The round goby depletes the food of most sport fish in the Great Lakes. The sport fish that are affected by this fish are bass, trout, perch, walleye and other gaming fish. The Neogobius melanostomus, or round goby, is native to the Caspian and Black Sea regions, including other tributaries (U.S. Army). There are three reasons the natural niche of the species prevented them from being a problem in their original environment: Reason One: Habitat is defined as the environment an organism lives in along with the factors that accompany the environment. The first reason why the Goby was not a problem is their habitat in the Ponto-Caspian Seas is the constant changes in salinity in the seas. There was an ever increasing salinity in the water which did not prevent the species to exist all the time (Sapota). During different parts of the year there is a high salinity, which prevents the some fish species from thriving. When the salinity is low that occurs from high river discharge and low intensity of salt water intrusions into the Baltic Sea (Ojaveer). The goby is very resilient to the salinity of water, so they can thrive in any condition because they outlive their predators. Reason Two: The second reason is the climate factors of the environment that the goby lived in. The climate is a hot climate which creates the higher temperature of water. The Ponto-Caspian seas are heated by the warm climate of the area. The round goby can
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Marschner 2 survive in water up to 31° C (Hayes). The Round Goby is able to overcome many adverse conditions that help them thrive in their native habitat. These fish are able to outlive the swarms of predatory fish that eat the Neogobius Melanostomus. Reason Three: Predators are the last reason they were not a problem is because when the predators were always controlling the population of the Goby. The goby was looked at as a constant food source because they were prevalent during the whole range of environmental conditions. Predatory fish knew this extraordinary fact, so they knew that there was always food readily available. In 1990, the Neogobius Melanostomus was first discovered in the St. Clair River near Detroit, Michigan (Great Lakes). Based on the research conducted from the article, “Great Lakes Grated by Round Goby,” this fish migrated from the Ponto-Caspian seas by the unregulated ballast water from trans-Atlantic shipping vessels. The goby can survive in water temperatures of 0-30° C and they are able to survive in areas with low water quality. With the resistance to these conditions the goby was able to survive in the ballast water tanks. Ballast tanks were an integral part for not only the ships of the mid 20 th century, but for the boats of present day 21 st century. Ballast tanks serve as a stability wing for ships that are carrying large amounts of cargo especially across an ocean. For example, a cargo vessel in the 1950s
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Invasive species - Marschner 1 Travis Marschner Mustafa...

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