Short description of Neogobius melanostomus, Round Goby

Small, soft-bodied, brownish-grey, dark brown lateral spots. Fused pelvic fin forms a ventral suction disc. Mature males black during spawning and nest-guarding, with yellowish spots. Large, oblong black spot usually at the end of first dorsal fin. Juveniles with light edge to the black spot.

Impact summary: Neogobius melanostomus, Round Goby

Direct impacts on native species by predation (young and eggs of other fishes, plus aquatic invertebrates, especially benthic species). Indirect impacts via competition for food and spawning habitat. Damage to fisheries. Vector for bioaccumulation of contaminants with potential human health impacts.

Habitat summary: Neogobius melanostomus, Round Goby

Bottom-dwelling in nearshore regions of lakes and in rivers, preferring rocky habitats that offer hiding opportunities, although also found with fine gravel and sandy substrates in which they can burrow.

Overview table

Environment	Freshwater
Species status	Non-Native
Native range	Black Sea coastline, Caspian Sea coast
Functional type	Predator
Status in England
Status in Scotland
Status in Wales
Location of first record
Date of first record	Unknown

Origin

Eastern Europe, Sea of Azov, Black Sea and Caspian basins. Central Asia (Kazakhstan, Uzbekistan, Turkmenistan) though some areas such as the Aral Sea may be considered outside the native range.

First Record

Not yet recorded in GB (9th Nov 2010), but identified as a possible new arrival through horizon-scanning.  In December 2004 two specimens were caught in the River Lek near Schoonhoven (The Netherlands), the first record of this fish in the North Sea basin (van Beek 2006). Since then, numerous individuals have been caught in different locations in the western part of the country. 

Pathway and Method

Not yet recorded in GB (9th Nov 2010).  Elsewhere, some spread is by diffusion (e.g. to Austria), or accidental via shipping in ballast water (e.g. to North America); in some cases the method of introduction is unknown.

Species Status

Invasive in North America (e.g. the Great Lakes), Austria, Sweden, Baltic Sea basin, Netherlands. Some adverse ecological effects reported i.e.  reduced abundance of native fish and benthic organisms directly through predation as well as indirectly via competition for food and spawning habitat (Fuller et al. 2009).

Dispersal Mechanisms

Some natural dispersal via river systems. Most dispersal leading to introductions is likely to be via shipping (e.g. in ballast water), with subsequent natural dispersal enhanced by local shipping. In the Great Lakes, MacInnis and Corkum (2000) note that the relatively high fecundity (compared with native species), rapid maturation, aggressive behaviour, and extended spawning season may also favour the  expansion of round gobies.

Reproduction

Males migrate from deeper waters to spawning areas in the spring, establishing territories prior to the arrival of females, then defending a nest site to which females are attracted, and caring for one or more batches of eggs (Murphy et al. 2001). As with other male gobiids, males use visual displays (colouration changes and posturing) and acoustic signals when courting females (Protasov et al. 1965, Moiseyeva & Rudenko 1976). Hayes (2008) states that females spawn repeatedly (approximately every 20 days with 500-3000 eggs being  deposited on a hard substrate) from April until September while males guard the eggs and young. Pheromone signalling is crucial to mating behaviour in N. melanostomus (Corkum 2004) with males releasing an attractant to which gravid females respond (Belanger et al. 2004).

Females mature by 1-2 years of age and males at 3-4 years (Hayes 2008). Newly colonised round gobies in brackish waters and lakes are smaller, mature earlier, have a male-biased sex ratio and are shorter-lived compared with round gobies from marine (native) habitats (Corkum et al. 2004).

Known Predators/Herbivores

General piscivory, especially by larger fish species.

Resistant Stages

None known.

Habitat Occupied in GB

No GB records (9th Nov 2010), but in other countries it is bottom-dwelling in the nearshore regions of lakes and in rivers, preferring rocky habitats that offer hiding opportunities. Although juveniles and adults both prefer rocky substrates, the fish also is found with fine gravel and sandy substrates in which they can burrow (Ray & Corkum 2001).

No GB records (9th Nov 2010).

Environmental Impact

N. melanostomus feeds on the young and eggs of other fishes, as well as aquatic invertebrates including crustaceans, molluscs, worms and insects, especially benthic species (Charlesbois et al. 1997). In the Sea of Azov, it was the primary consumer of the benthos, consuming up to 13% of annual production. Its diet during the primary feeding period (spring-autumn) was 90% molluscs, and during winter was 11-42% fish (Skazkina & Kostyuchenko 1968). Thus, this species can have adverse impacts on native fish and benthos directly through predation as well as indirectly via competition for food and spawning habitat. Fuller et al. (2009) state that the abundance of native fish species have declined in areas where N. melanostomus has become abundant.

Adults aggressively defend spawning sites and may prevent their use by native species out. ANSRP (2003) states that the ability of N. melanostomus to feed in darkness (due to its complete lateral line sensory system) may allow it to out-compete native fish for food. This effect may be enhanced by the suctorial disc formed by their pelvic fin which allows them to attach to substrates and remain fixed in faster currents. The authors also state that the species causes interference with habitat restoration projects.

Health and Social Impact

Hayes (2008) states that N. melanostomus eats bivalves that filter the water, and is a vector for bioaccumulation of contaminants. These are passed on to larger game fish that prey on this species and then possibly on to humans.

A nuisance fish to anglers because it is known to take bait.

Possible loss of amenity value due to its ecosystem effects.

Economic Impact

In the US, there have been significant impacts on commercial fisheries. For example, the state of Ohio has had to close its smallmouth bass fishery in Lake Erie during the months of May and June. This is due to high predation rates of nests by N. melanostomus which had adversely affected smallmouth bass recruitment.  Usually, male smallmouth bass guard nests and are effective in keeping round gobies away, but where  males have been removed (e.g. by predation), round gobies immediately invade and have been shown to eat up to 4,000 eggs within 15 minutes. With May and June normally accounting for half of the total smallmouth catch in Lake Erie, there has been a "considerable loss in funds generated by recreational fishers" (National Invasive Species Council 2004).

As well as adverse economic impacts associated with damage to native fisheries, there may be costs associated with tackling ecosystem damage and monitoring the species if it is introduced into Britain. Any subsequent eradication attempts would incur further costs as does current research into control of round goby e.g. the project detailed by Mensinger (2010) is costed at around $175,000.

The State of Ohio has shut down the smallmouth bass fishery in Lake Erie during the months of May and June.  The reason is that high predation rates on nests are affecting smallmouth recruitment.  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 have 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).

Identification

Miller, P.J. & Loates, M.J. (1997) Fish of Britain & Europe. HarperCollins, London.

Biology, ecology, spread, vectors

Belanger, A.J., Arbuckle, W.J., Corkum, L.D., Gammon, D.B., Li, W., Scott, A.P. & Zielinski, B. (2004) Behavioural and electrophsiological responses by reproductive female Neogobius melanostomus to odours released by conspecific males. Journal of Fish Biology, 65: 1-14.

Corkum, L.D. (2004) Pheromone signaling in conservation. Aquatic Conservation Marine & Freshwater Ecosystems, 14: 327-331.

Hayes, R. (2008) Neogobius melanostomus (online), Animal Diversity Web. [accessed 09/11/2010].

ISSG database (2006) Neogobius melanostomus: Ecology. [accessed 09/11/2010].

MacInnis, A. J. & Corkum, L.D. (2000) Age and growth of round goby Neogobius melanostomus in the upper Detroit River. Transactions of the American Fisheries Society, 129(3), 852-858.

Moiseyeva, Y. B. & Rudenko, V. I. (1976) The spawning of the round goby, Gobius melanostomus, under aquarium conditions in winter. Journal of Ichthyology, 8, 690–692.

Murphy, C.A., Stacey, N.E., & Corkum, L.D. (2001) Putative steroidal pheromones in the round goby, Neogobius melanostomus: olfactory and behavioural responses. Journal of Chemical Ecology, 27, 443-470.

Protasov, V. P., Tzvetkov, V. I., & Rashcheperin, V. K. (1965) Acoustical signals in the Azov round goby Neogobius melanostomus (Pallas). Zh. Obshch. Biol., 26, 151–159.

Ray, W.J. & Corkum, L.D. (2001) Habitat and site affinity of the round goby. Journal of Great Lakes Research, 27(3), 329-334.

van Beek, G.C.W. (2006) The round goby Neogobius melanostomus first recorded in the Netherlands. Aquatic Invasions, 1, 42-43.

Management and impact

ANSRP (Aquatic Nuisance Species Research Program) (2003) Neogobius melanostomus - Round Goby. US Army Corps of Engineers: Engineer Research and Development Center. [accessed 09/11/2010].

Charlebois, P.M., Marsden, J.E., Goettel, R.G., Wolfe, R.K., Jude, D.J., & Rudnika, S. (1997) The Round Goby (Neogobius melanostomus Pallas). A Review of European and North American Literature. Illinois-Indiana Sea Grant Program and Illinois Natural History Survey. INHS Special Publication, No. 20.

Chotkowski, M. & Marsden, J.E. (1995) Round goby predation on native lake trout eggs, p. 82 In: Proceedings of the 38th Conference of the International Association of Great Lakes Research. Ann Arbor, MI 48109-2099 USA.

Corkum, L. D. & Belanger, R. M. (2007) Use of chemical communication in the management of freshwater aquatic species that are vectors of human diseases or are invasive. Gen. Comp. Endocrinol., 153, 401-417.

Fuller. P., Benson, A. & Maynard, E. (2009) Neogobius melanostomus. USGS Nonindigenous Aquatic Species Database. [accessed 09/11/2010].

Hayes, R. (2008) Neogobius melanostomus (online), Animal Diversity Web. [accessed 09/11/2010].

Mensinger, A.F. (2010). Bioacoustic traps for the management of the round goby. [accessed 09/11/2010].

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

Natural England (2009) Horizon scanning for new invasive non-native animal species in England. [accessed 10/11/2010].

Schreier, T.M., Dawson, V.K. & Larson, W. (2008) Effectiveness of Piscicides for Controlling Round Gobies (Neogobius melanostomus). Journal of Great Lakes Research, 34(2), 253-264.

Skazkina, E. P. & Kostyuchenko, V.A. (1968) Food of N. melanostomus in the Azov Sea. Vopr. Ikhtiol., 8, 303-311.

Sorensen, P. W. & Stacey, N. E. (2004) Brief review of fish pheromones and discussion of their possible uses in the control of non-indigenous teleost fishes. New Zealand Journal of Marine and Freshwater Research, 38, 399-417.

World Fishing & Aquaculture (2010). Governments urged to finalise ballast water's invasive species rules. [accessed 09/11/2010].

General

Fishbase. Neogobius melanostomus. [accessed 09/11/2010].

https://www.cabi.org/isc/datasheet/73163