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Grade 9 Applied Science – Biology Round Goby Fish Sources - Federation of Anglers and Hunters. Viewed 2012. Round Goby. Ontario Invasive Species Awareness Program. (Online) Available: http://www.invadingspecies.com/invaders/fish/round-goby/ The round goby (Neogobius melanostomus) is a small, bottom-dwelling fish. It is commonly found in the Black and Caspian Seas in Eastern Europe. In North America, the round goby is an invasive species. Brought in the ballast of ocean-going ships, the round goby was found in 1990 in the St. Clair River. In less than a decade, the round goby had spread through all five Great Lakes and into inland waters. In some areas the fish has reached densities of more than 100 fish per square metre. Round goby prefer waters with rocky and sandy bottoms. They feed aggressively on insects and other small organisms. As well, adult round goby eat large quantities of zebra and quagga mussels, and occasionally, small fish and fish eggs. Their aggressive eating habits PLUS ability to spawn several times each season AND survive in poor water quality have helped the round goby outcompete native fish species, occupy prime habitats and spread quickly. Invasive Range The round goby has been found in all five Great Lakes and many of their tributaries, including the Illinois River. Round goby are also found in some inland waters in southern Ontario such as Lake Simcoe, Trent River, Rice Lake and parts of the Otonabee River. Impacts of Round Goby The round goby has negatively impacted the natural ecosystem of the Great Lakes ecosystem. The fish compete with and prey on native bottom-dwelling fish such as mottled sculpin (Cottus bairdii) and logperch (Percina caprodes). Round goby also threaten several species at risk in the Great Lakes Basin including the northern madtom (Noturus stigmosus), the eastern sand darter (Ammocrypta pellucida), and several species of freshwater mussels. Round goby have reduced populations of sport fish by (1) eating the sport fish eggs and young and (2) competing for food sources. Round goby may be linked to outbreaks of botulism type E in Great Lakes fish and fish-eating birds. The disease is caused by a toxin that may be passed from zebra mussels via goby to birds, resulting in large dieoffs of fish and birds. To prevent the spread of this invasive species, the Ontario government has banned the possession of live round goby and the use of round goby as a baitfish. Identifying Round Goby Adult round goby are small (6-16 cm long) with a cylindrical body, a rounded to blunt snout and fish-like eyes. The round goby looks similar to several species of fish found in the Great Lakes including the invasive tubenose goby (Proterorhinus semilunaris) and native sculpins (Myoxocephalus thompsoni and Cottus sp.). Round Goby (Invasive) Tubenose Goby (Invasive) Sculpin (Native) Prominent black spot Fused scallop-shaped pelvic fin AND full-scaled body Body is brownish or olive in color, with dark brown spots. Except in reproducing males, the body and fins are almost completely black Nostril tubes do not reach the upper lip No black spot. Fused scallop-shaped fin AND full-scaled body Body is grey, light brown, olive or tan with black or reddish-brown mottling on the back Small nostril tubes extend over the upper lip No black spot on dorsal fin Two separate pelvic fins Body has a mottled-colour pattern with a cream coloured belly Nostril tubes do not reach upper lip No scales Source – US Geological Survey. 2012. Round Goby - Nonindigenous Aquatic Species. (Online). Available: http://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=713 Impact of Introduction The round goby typically occupy inshore habitats with cover, especially plants or rocky rubble; yet, they can migrate to deeper water (50-60 m) in winter (Jude et al., 1992). The numbers of native fish species have declined in areas where the round goby has become abundant (Crossman et al., 1992). Round goby prey on darters, other small fish and lake trout eggs and fry, plus they may feed on eggs and fry of sculpins, darters, and logperch (Marsden and Jude, 1995). They also compete with rainbow darters (Etheostoma caeruleum), logperch (Percina caprodes), and northern madtoms (Noturus stigmosus) for small macroinvertebrates (French and Jude, 2001). Mottled sculpins (Cottus bairdi) have been particularly effected due to competition for spawning sites, space and food, as well as interference during nesting (e.g., egg consumption) (Janssen and Jude 2001). Adults aggressively defend spawning sites and occupy prime spawning areas, keeping natives out (Marsden and Jude 1995; Dubs and Corkum 1996). In Calumet Harbor, there has been an absence of mottled sculpin nests and fish aged 0 since 1994, coinciding with N. melanostomus establishment (Janssen and Jude 2001). Neogobius melanostomus and C. bairdi both take daytime refuge from predators under rocks, emerging to feed nocturnally (Dubs and Corkum 1996). This space competition could displace C. bairdi into deeper and unprotected spaces where they can easily be predated. The diet of adult round gobies consists mainly of zebra mussels, which no other fish species of the Great Lakes consumes. This allows round gobies to uniquely exploit a resource that could fuel a population explosion (Vanderploeg et al. 2002). The invasion of round gobies into Lake Erie has had very real environmental and economic impacts. Ohio has shut down the smallmouth bass fishery in Lake Erie during the months of May and June. Under normal circumstances, male smallmouth bass guard nests and are effective in keeping round gobies away. When males are removed, round gobies immediately invade and eat nearly 4,000 eggs within 15 minutes. The months of May and June normally account for 50 percent of the total smallmouth catch in Lake Erie. Thus. there is a considerable loss (National Invasive Species Council 2004). Round goby introductions may also be a vector for the spread of avian botulism. The change in behavior of infected gobies make them preferred prey items to piscivorous birds (Yule et al. 2006). At Lake Erie, botulism infected birds had been feeding more on round goby compared to uninfected birds (Corkum et al. 2004). Not all impacts of the introduced round goby are negative. Round gobies comprise the majority of the diet for Lake Erie water snakes (Nerodia sipedon insularum), and the abundance of gobies has been credited for the increase in population size, increased growth rates, and larger body size of the snakes (King et al. 2006). Due to their increase in abundance, the Lake Erie water snake was removed from the USA Endangered Species List in 2011. In addition, round gobies provide an abundant food source for several sportfishes including walleye, yellow perch and largemouth/smallmouth bass (Taraborelli et al. 2010). Sources Corkum, L.D., M.R. Sapota and K.E. Skora. 2004. The round goby, Neogobius melanostomus, a fish invader on both sides of the Atlantic Ocean. Biological Invasions 6: 173-181. Crossman, E.J., E. Holm, R. Cholmondeley and K. Tuininga. 1992. First record for Canada of the rudd, Scardinius erythrophthalmus, and notes on the introduced round goby, Neogobius melanostomus. Canadian Field-Naturalist 106(2):206-209. Dubs, D.O.L. and L.D. Corkum. 1996. Behavioral interactions between round gobies (Neogobius melanostomus) and mottled sculpins (Cottus bairdi). Journal of Great Lakes Research 22:838-845 French, J.R.P, III and D.J. Jude. 2001. Diets and diet overlap of nonindigenous gobies and small benthic native fishes coinhabiting the St. Clair River, Michigan. Journal of Great Lakes Research 27(3):300-311. Janssen, J. and D.J. Jude. 2001. Recruitment failure of mottled sculpin Cottus bairdi in the Calumet Harbor, southern Lake Michigan, induced by the newly introduced round goby Neogobius melanostomus. Journal of Great Lakes Research 27(2):319-328. Jude, D.J., R.H. Reider and G.R. Smith. 1992. Establishment of Gobiidae in the Great Lakes Basin. Canadian Journal of Fisheries and Aquatic Sciences 49:416-421. King, R.B., J.M. Ray, and K.M. Stanford. 2006. Gorging on gobies: beneficial effects of alien prey on a threatened vertebrate. Canadian Journal of Zoology 84:108-115. Marsden, J.E. and D.J. Jude. 1995. Round gobies invade North America. Fact sheet produced by Sea Grant at Ohio State University, Columbus, OH. National Invasive Species Council. 2004. Weekly Notice May 27, 2004-June 3, 2004. Taraborelli, A.C., M.G. Fox, T.B. Johnson and T. Schaner. 2010. Round goby (Neogobius melanostomus) population structure, biomass, prey consumption, and mortality from predation in the Bay of Quinte, Lake Ontario. Journal of Great Lakes Research 36:625-632. Vanderploeg, H.A., T.F. Nalepa, D.J. Jude, E.L. Mills, K.T. Holeck, J.R. Leibig, I.A, Grigorovich and H. Ojaveer. 2002. Dispersal and emerging ecological impacts of Ponto-Caspian species in the Laurentian Great Lakes. Canadian Journal of Fisheries and Aquatic Sciences 59:1209-1228. Yule, A.M., I.K. Barker, J.W. Austin and R.D. Moccia. 2006. Toxicity of Clostridium botulinum Type E neurotoxin to Great Lakes fish: implications for avian botulism. Journal of Wildlife Diseases 42(3):479-493.