Download Grade 9 Applied Science – Biology

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)
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Tubenose Goby (Invasive)
Sculpin (Native)
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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
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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
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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
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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.
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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.
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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
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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.
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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.
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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.
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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.
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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.
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National Invasive Species Council. 2004. Weekly Notice May 27, 2004-June 3, 2004.
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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.
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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.
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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.