Apollonia melanostoma (Pallas, 1814), Apollonia melanostomus (Pallas, 1814); see Stepien and Tumeo (2006) for name change, and Stepien and Neilson (2013) for clarification on taxonomy and nomenclature.

Female round gobies mature at 1-2 years with clutch (100-4000 eggs) related to body size.  They can spawn every 20 days from April to September and have a maximum lifespan of about 4 years.  Round goby has been shown to exhibit phenotypic plasticity in some life history characteristics, such as reproductive traits like number and size of mature oocytes, and this plasticity has been suggested to enhance establishment success at invasion fronts (Hôrková and Kovác 2015). Phenotypic plasticity has also been shown in Round goby to maintain or regain homeostasis after rapid temperature changes, thus increasing its invasion success (Wellband and Heath 2017).

The Round goby has a well-developed sensory system that enhances its ability to detect water movement. This allows it to feed in complete darkness, giving it an advantage over other fish in the same habitat (Wisconsin Sea Grant 2008). Round goby also forage efficiently in structured habitats that might otherwise serve as prey refugia (Gebauer et al 2019).

Round goby are dietary generalists feeding on both invertebrates – Dreissenid mussels, fingernail clams, small native mussels and snails, soft-shelled crayfish, Ephemeroptera, Plecoptera, Trichoptera, Chironomidae, Ceratapogonidae, Diptera, Odonata, Oligochaeta, Ostracoda, Isopoda, Amphipoda,  Mysidae, and large Cladocerans (Jude et al 1992, Jude et al 1995, Ray and Corkum 1997, French and Jude 2001, Ricciardi 2001, Phillips et al 2003, Barton et al 2005, Hogan et al 2007, Walsh et al 2007, Krakowiak and Pennuto 2008, Polacik et al 2009, Kipp et al 2012) – as well as on small fishes and fish eggs (Crossman et al 1992, Jude et al 1995, Marsden and Jude 1995, Ray and Corkum 1997, Chotkowski and Marsden 1999, French and Jude 2001, Jude 2001, Ricciardi 2001, Hensler and Jude 2007, Gebauer et al 2018, Gebauer et al 2019, LeBlanc et al 2019).  The zebra mussel (Dreissena polymorpha) may have facilitated the invasion of the Round goby by providing an abundant food source (Ricciardi and MacIsaac 2000). 

Round gobies, particularly young gobies, are eaten by many native Great Lakes fishes including Lake Trout (Salvelinus namaycush), Smallmouth Bass (Micropterus dolomieu), Mottled Sculpin (Cottus bairdii), Northern Madtom (Noturus stigmosus), Burbot (Lota lota) and Lake Sturgeon (Acipenser fulvescens)  (French and Jude 2001, Steinhart et al 2004, Dietrich et al 2006, Brey 2006, Hogan et al 2007, Taraborelli et al 2010, Madenjian et al 2011, Crane and Einhouse 2016, Jacobs et al 2017).

Round goby is one of the most frequently found prey items in the diet of the Double-Crested Cormorant (Phalacrocorax auritus) (Van Guilder and Seefelt 2013, Madura and Jones 2016). Round Gobies now 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).

Established outside of the Great Lakes basin in 1994 (Dennison, personal communication), and in 2010 spread into the lower Illinois River (K. Irons, Illinois Natural History Survey, Champaign, IL, personal communication).

Summary of species impacts derived from literature review. Click on an icon to find out more...

Environmental	Socioeconomic	Beneficial

Together with dreissenid mussels, Round gobies have shifted the Great Lakes food web from a pelagic-base to a benthic-base (Hogan et al 2007).

The numbers of native fish species have declined in areas where the Round goby has become abundant (Crossman et al. 1992). Invasion of the Round goby appears to have been primarily responsible for local extirpations of the greenside darter (Etheostoma blennoides), Johnny darter (Etheostoma nigrum), fantail darter (Etheostoma flabellare), rainbow darter (Etheostoma caeruleum) and mottled sculpin (Cottus bairdii) (Baltz and Moyle 1993, Jude et al 1995, Marsden and Jude 1995, Janssen and Jude 2001. French and Jude 2001, Lauer et al 2004, Jude et al 2018).  Several native benthic-feeding fish such as perch (Perca spp.), sculpin (Cottus spp.), darter (Etheostoma spp.), and logperch (Percina spp.) have shown a decline in numbers since the invasion of the Round goby (Jude et al 1995, Thompson and Simon 2014, Zuerwink et al 2019). These declines are likely due to a combination of competition with Round goby for food and/or space along with Round goby consumption of eggs and young fish (Jude et al 1992, Jude et al 1995, Marsden and Jude 1995, Dubs and Corkum 1996, Jansson and Jude 2001, Balshine et al. 2005).

Round goby has been demonstrated to compete with rainbow darter (Etheostoma caeruleum), logperch (Percina caprodes), the endangered northern madtom (Noturus stigmosus), and the threatened Eastern Sand Darter (Ammocrypta pellucida) for small macroinvertebrates (French and Jude 2001, Poos et al 2010, Burkett and Jude 2015). Slimy sculpins (Cottus cognatus) were able to maintain their weight in the presence of the Round goby; however, spoonhead sculpins (Cottus ricei) and logperch (Percina caprodes) lost a significant amount of weight during the trials (Bergstrom and Mensinger 2009).

Round goby may compete with and have the potential to affect other benthic fishes throughout the Great Lakes including darters (Etheostoma spp., Percina spp.), sculpins (Cottus cognatus, Myoxocephalus thompsoni, Cottus ricei), and madtoms (Noturus spp.) (Jude et al 1995, MacInnis and Corkum 2000, French and Jude 2001).  Round goby predation on Mysis relicta may result in competition with the three most common offshore fishes of Lake Ontario – alewife (Alosa pseudoharengus), rainbow smelt (Osmerus mordax) and slimy sculpin (Cottus cognatus)- as well as juvenile lake trout (Salvelinus namaycush) which all rely on Mysis (Walsh et al 2007)

Round gobies can seriously impact benthic invertebrate populations as well as fish.  Decreases in benthic invertebrate biomass of all or some taxa as well as shifts in community composition have been observed in both the lakes and tributaries (Kuhns and Berg 1999, Lederer et al 2006, Krakowiak and Pennuto 2008, Kipp et al 2012). In LeBoeuf and French creeks, Pennsylvania, native juvenile unionid mussels comprised a significant portion of Round goby diets.(Bradshaw-Wilson 2019).  In addition to potential predation on unionids, gobies may further impact rare and endangered freshwater mussels by altering populations of host fishes that the mussels need to complete their lifecycle, during which they are required to attach to host fish as glochidia and grow (Poos et al. 2010, Bradshaw-Wilson et al 2019).

Impacts may vary with habitat.  Gebauer et al (2019) found significant differences in Round goby attack rate and handling time as well as feeding rates with varied habitats with foraging efficiencies clearly higher in structured habitats on hard substrates (gravel).  Impacts seen in the Great Lakes also may not be reflected in tributaries.  Kornis et al 2013 found no changes in abundance of Johnny darter (Etheostoma nigrum), Logperch (Percina caprodes) or Blackside darter (Percina maculata)(despite diet overlap) following Round goby invasion and increase in abundance because they preferred separate stream habitats.  They also found round gobies, mottled sculpin, and yellow perch share habitat preferences in the Great Lakes but not in tributaries. In tributaries species negatively associated with round gobies are unlikely to co-occur due to preference for habitat characteristics sub-optimal for Round goby, including tolerance of low oxygen conditions (Central mudminnow – Umbra limi), watersheds with higher slope and faster flow (Rainbow trout – Oncorhynchus mykiss, Brook stickleback – Culaea inconstans), and cooler temperature (Mottled sculpin – Cottus bairdii).

Round goby, via predation on zebra and quagga mussels, likely has the ability to facilitate the bioaccumulation of contaminants up the food chain to benthic-oriented piscivores that feed on Round goby, although experimental results with various contaminants vary (Jude et al 1995, Hogan et al. 2007, Morrison et al. 2000, Brey 2006, Ng et al. 2008, Almqvist et al 2010, Macksasitorn et al 2015, Sun et al 2016).  Despite a decline in sediment mercury concentrations in Lake Erie, smallmouth bass continued to accumulate mercury at historical rates, possibly because of their high consumption rate of the benthivorous Round goby. As smallmouth bass continue to consume round gobies and their growth rates continue to increase, their mercury concentrations also may continue to increase, potentially increasing mercury contamination to humans consuming this important sport fish (Hogan et al 2007). In contrast, round gobies may have lower lead concentrations than traditional prey due to their consumption of zebra mussels which efficiently excrete metals; therefore round gobies in smallmouth bass diets may contribute to further diminution and lower concentrations of lead in smallmouth bass (Hogan et al 2007).

Neogobius melanostomus introductions may also be a vector for the spread of avian botulism. In Lake Erie, botulism infected birds had been feeding more on Round goby compared to uninfected birds (Corkum et al. 2004).The change in behavior of infected N. melanostomus may make it a preferred prey item for piscivorous birds (Yule et al. 2006, Kornis et al 2012). Sturgeon and other large piscivorous fish have also been affected (Jude 2021, Pers. Comm.)

Neogobius melanostomus has a high socio-economic impact in the Great Lakes.

The State of Ohio has shut down the Smallmouth Bass (Micropterus dolomieu) fishery in Lake Erie during the months of May and June because high predation rates on nests are affecting smallmouth recruitment. Under normal circumstances, male Smallmouth Bass guard nests and are effective in keeping Round goby away. When males are removed, the Round goby immediately invades and has been shown to eat up to 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, so there will be a considerable loss in funds generated by recreational fishers (National Invasive Species Council 2004).

In a survey-based study Dunning et al (2006) found that Round goby catches led to a perception of poor fishing quality and frustration among anglers.  Anecdotal information from throughout the Great Lakes basin reflects this frustration (Marsden and Jude 1995, Jude and DeBoe 1996). 

Round goby, via predation on zebra and quagga mussels, has the ability to facilitate the bioaccumulation of contaminants (PCBs, Mercury, botulism) up the food chain to benthic-oriented piscivores that feed on Round goby eventually increasing contamination to humans consuming sport fish (Jude et al 1995, Hogan et al. 2007, Morrison et al. 2000, Brey 2006, Ng et al. 2008, Almqvist et al 2010, Macksasitorn et al 2015, Sun et al 2016).

Neogobius melanostomus has moderate beneficial effects in the Great Lakes.

Round goby consume zebra and quagga mussels; a substantial gap in the invasive-impacted food web is thus lessened (Vanderploeg 2002, Johnson et al. 2005).    Round goby appeared to make up approximately 75% of Burbot (Lota lota) and Smallmouth Bass (Micropterus dolomieu) diet in Lake Erie and 36% of Lake Trout (Salvelinus namaycush) diet in Lake Ontario, indicating that a new energy source may be travelling up the food chain (Dietrich et al. 2006, Johnson et al. 2005). Round Gobies comprise the majority of the diet for endangered 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).  Round goby was also the most important Lake Sturgeon (Acipenser fulvescens) prey item (86% by weight) in 2014 (Jacobs et al 2017). Round goby also supplements the diet of Yellow Perch (Perca flavescens) (Weber et al. 2011) and is preyed on at least occasionally by a host of other Great Lakes fishes.  Brey (2006) speculates switch from alewife (Alosa psuedoharengus) to Round goby may be beneficial as round gobies do not cause thiamine deficiencies (as alewife do).

Consumption of dreissenids by Round goby likely has little impact in controlling dreissenid populations; one study estimates that predation affected only 1% of the dreissenid population of Lake Erie (Johnson et al 2005).  Competition from (or predation by) Round goby may be partially responsible for keeping invasive Great Lakes tubenose goby (Proterorhinus semilunaris) population in check (Ricciardi 2001, Nagelkerke et al 2018, Cartwright et al 2019, Gebauer et al 2019).

Note: Check federal, state/provincial, and local regulations for the most up-to-date information.
 

Control
Biological
Although many other species consume Round Goby, no effective and species-specific biocontrol has been identified. Among other species, native Burbot are being investigated for their potential to control goby populations (Madenjian et al. 2011).

Physical

Chemical
The IJC (2011) recommends rotenone for control of Round Goby in rapid response scenarios. Of the four chemical piscicides registered for use in the United States, antimycin A and rotenone are considered “general” piscicides, but no studies have been found of their effects on Neogobius melanostomus (GLMRIS 2012).

Increasing CO₂ concentrations, either by bubbling pressurized gas directly into water or by the addition of sodium bicarbonate (NaHCO₃) has been used to sedate fish with minimal residual toxicity, and is a potential method of harvesting fish for removal, though maintaining adequate CO₂ concentrations may be difficult in large/natural water bodies (Clearwater et al. 2008). CO₂ is approved only for use as an anesthetic for cold, cool, and warm water fishes the US, not for use as euthanasia, and exposure to NaHCO₃ concentration of 142-642 mg/L for 5 min. is sufficient to anaesthetize most fish (Clearwater et al. 2008).

It should be noted that chemical treatment will often lead to non-target kills, and so all options for management of a species should be adequately studied before a decision is made to use piscicides or other chemicals. Potential effects on non-target plants and organisms, including macroinvertebrates and other fishes, should always be deliberately evaluated and analyzed. The effects of combinations of management chemicals and other toxicants, whether intentional or unintentional, should be understood prior to chemical treatment. Other non-selective alterations of water quality, such as reducing dissolved oxygen levels or altering pH, could also have a deleterious impact on native fish, invertebrates, and other fauna or flora, and their potential harmful effects should therefore be evaluated thoroughly.

Other
Electrical barriers may be successful at limiting the movement of Round Gobies. In tank studies, Round Gobies did not move through such a barrier (Savino et al. 2001).

Rollo et al. (2007) reported Round Gobies will approach a speaker emitting conspecific male calls in the field, and female Round Gobies showed significant attractions to speakers emitting conspecific male calls in the laboratory. Therefore Round Goby phonotaxis could be used to lure gravid females to traps. As Round Gobies will spawn multiple times throughout late spring and summer, they should remain receptive to male calls and bioacoustic capture for the entire breeding season.

Ochs et al. (2013) found no response to putative Round Goby pheromones by several syntopic Great Lakes native centrarchids and percids, indicating the potential for pheromone trapping as a viable control method.

Note: Check state/provincial and local regulations for the most up-to-date information regarding permits for control methods. Follow all label instructions.

Adrian-Kalchhauser et al. (2017) suggest that there is no direct evidence for the direct attachment of egg clutches by Round goby to aquatic vessels, a commonly suggested introduction vector for Ponto-Caspian gobiids, and that this concept should be treated as an untested hypothesis.

Pettitt-Wade et al. (2015) examined trophic niche breadth, plasticity, and overlap between Round and Tubenose gobies in Lakes Superior and St. Clair using stable isotope analysis. They found a higher isotopic trophic position and generally higher isotopic nichc breadth and plasticity in Round Goby, with little overlap between size-matched Round and Tubenose gobies, and suggested that this increased isotopic niche breadth and plasticity has assisted in the establishement success of Round Goby in the Great Lakes (widely abundant and distributed vs. low abundance and localized distribution of tubenose goby).

Introduced populations of Round Goby in the Great Lakes show reduced diversity and numbers of parasites compared to populations from its native range as well as to native Great Lakes fishes, providing some support for the 'enemy release hypothesis' for invasion success (Kvach and Stepien 2008; Gendron et al. 2012). However, Gendron et al. (2012) found that gobies from Lake St. Clair (one of the earliest introduced populations) showed an increase in parasite diversity and density over time. Similar results are apparent in Lake Erie (Kvach and Stepien 2008) and Lake Michigan (Camp et al 1999). Additional studies of introduced and native populations in Europe (Kvach et al 2014, Ondrackova et al 2015, Kvach et al 2017, Ovcharenko et al 2017, Mineeva 2019) also indicate that that enemy release is a transient effect seen only in early stages of invasion.

Round Goby has been shown to exhibit phenotypic plasticity in some life history characteristics, such as reproductive traits like number and size of mature oocytes, and this plasticity has been suggested to enhance establishment success at invasion fronts (Hôrková and Kovác 2015). Phenotypic plasticity has also been shown in Round Goby to maintain or regain homeostasis after rapid temperature changes, thus increasing its invasion success (Wellband and Heath 2017).

Voucher specimens: Ohio (OSM, UF 98888); Michigan (UMMZ); Illinois (INHS). Indiana (INHS, UMMZ 224874). Voucher specimens from the Canadian side of the St. Clair River (UMMZ 217682, 218279; ROM 60675); Lake Ontario (Ontario Federation of Anglers and Hunters, Peterborough, Ontario).