70 clearing waterways which also promotes biodiversity.2 Rusty Crayfish are frequently used as bait for fishing and can be eaten, both of which make them economically valuable in their native ranges. The Round Goby is also native to the Caspian and Black Seas and is important for controlling the population of other native species. Notably, they eat Zebra Mussels and other crustaceans.3 They are aggressive in nature and easily outcompete other fish in both their native and invasive habitats.4 The introduction of Zebra Mussels in North America was accidental and likely unavoidable given the economic importance of the Great Lakes system for the transportation of goods. The first record of the muscles in the Great Lakes system was in 1988 and the generally accepted consensus is that they likely came from ballast water that was discharged by cargo ships into the lakes.5 Interestingly, the presence of these mussels in the Fox can be almost entirely attributed to Soviet-US trade agreements. After a series of failed crops in the 1980’s the Soviet Union was in desperate need of grain to sustain their agricultural industry, so President Ronald Reagan struck a trade deal that allowed for millions of dollars of Midwest grain to be shipped to Russia. Importantly, there were few goods that the US wanted in return for this grain, so ships were sent almost entirely empty from the Soviet Union to the Great Lakes system.6 An empty cargo ship must fill its tanks with ballast water, and thus millions of tons of Eurasian water was emptied into the Great Lakes throughout the 1980s, likely resulting in the introduction of Zebra Mussels.7 Not only was this introduction influenced by global political conditions, large scale environmental factors were also at play. This deal was 2 Julian D. Olden, M. Jake Vander Zanden, and Pieter T. Johnson, “Assessing Ecosystem Vulnerability to Invasive Rusty Crayfish (Orconectes Rusticus),” Ecological Applications 21, no. 7 (October 2011): pp. 2587-2599, https://doi.org/10.1890/10-2051.1, 2588. 3 Dave Bosanko, “Goby Family,” in Fish of Minnesota Field Guide (Cambridge, MN: Adventure Publications, 2019), pp. 56-58. 4 Ibid. 5 “Ballast Water and Nonindigenous Species,” in Stemming the Tide Controlling Introductions of Nonindigenous Species by Ships' Ballast Water (Washington, D.C.: National Academy Press, 1996), 11-14. 6 Science, W., & Board, T, Great Lakes Shipping, Trade, and Aquatic Invasive Species Special Report 291. (Washington D.C., District of Columbia), p. 43-62 7 Jonathan M. Bossenbroek et al., “Forecasting the Expansion of Zebra Mussels in the United States,” Conservation Biology 21, no. 3 (December 2007): pp. 800-810, https://doi.org/10.1111/j.1523-1739.2006.00614.x.
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