Information Last Reviewed Spring 2007
An amphipod native to the Ponto-Caspian region, Dikerogammarus villosus has recently invaded and spread throughout western Europe. Its populations have caused significant ecological disruption, including reduced biodiversity and local species extinction. Although not yet known from North America, there is major concern about the potential environmental impact of this amphipod, should it be introduced.
Kills its prey by biting and shredding them
Much more deadly predator than native amphipods (partially due to its much larger and more powerful mouthparts)
Attacks and eliminates other gammarid species
Colonizes a wide variety of substrates, is capable of adapting to a wide range of habitats, and is able to survive fluctuations in temperature, salinity, and oxygen levels
Total body length of up to 30 mm (relatively large for a freshwater amphipod)
May appear striped or uniform in coloration pattern (Fig. 2)
Mandibles are relatively large
Behavior is particularly vicious and destructive, killing and maiming unselectively
Newly released young resembling adults, but microscopic in size
As with other arthropods, develop an exoskeleton, molting several times as they increase in size
Sexual maturity reached at 6 mm in length
Populations are predominantly female
Exceptionally high growth rates (e.g., 1.3-2.9 mm per month during the winter and 2.0-2.6 mm over a two-week period in spring)
Reproduce sexually, high fecundity
Reproduction occurs year round
During mating, male carries smaller female on his back (i.e., amplexus)
Female can carry approximately 50 fertilized eggs and releases them into the ventral brood chamber, where they are incubated and develop
Fresh and brackish waters
Lakes, rivers, and canals
Able to colonize all types of fastened banks, sheet-pile walls, and especially mats of algae near or on the water surface
Following invasion of the River Rhine, D. villosus became the dominant species on stone substrates where it out-competed other species including Gammarus tigrinus (a strongly competitive species native to North American waters)
Eurythermic (i.e., tolerant to wide range of temperature changes)
Optimal metabolic temperatures are between 20 and 23 deg C
Upper thermal limits between 30 and 35 deg C
Tolerant of low dissolved oxygen
Highest oxygen consumption occurred at 20 deg C
Prefers fresh and brackish waters (0‰-10‰ salinities)
Able to adapt to salinities of 20‰
Intolerant of salinities >24‰
Danube and its tributaries in central-eastern Europe
North American Distribution
Has never been recorded
Probable Means of Introduction
Invasion predicted via ballast tanks from European ships
Voracious predator of macroinvertebrates, including other gammarids
Interactions between D. villosus and native gammarid species can result in displacement or local extinction of native species, thereby reducing biodiversity
D. villosus has been observed attacking small fish, which raises concern over whether vulnerable life stages (eggs, larvae, and juveniles) of vertebrates may also be at risk
May be an intermediate host of acanthocephalan worms (a parasite of birds and fish)
Mandatory ballast control
Shoreside treatment plants, where ship ballast water could be unloaded, treated, and safely released, are being considered, but this could be an expensive option
Filtration systems and chemical use for ship ballast are also options being considered
Bij de Vaate, A. and Klink, A. G. 1995. Dikerogammarus villosus Sowinsky (Crustacea: Gammaridae), a new immigrant in the Dutch part of the Lower Rhine. Lauterbornia 20:51-54.
Bruijs, M. C. M., Kelleher, B., van der Velde, G., and bij de Vaate, A. 2001. Oxygen consumption, temperature and salinity tolerance of the invasive amphipod Dikerogammarus villosus: Indicators of further dispersal via ballast water transport. Archiv für Hydrobiologie 152:633-646.
Devin, S., Beisel, J. N., Bachmann, V. and Moreteau, J. C. 2001. Dikerogammarus villosus (Amphipoda:Gammaridae): Another invasive species newly established in the Moselle River and French hydrosystems. Annales de Limnologie - International Journal of Limnology 37:21-27
Devin, S., Piscart, C., Beisel, J. N. and Moreteau, J. C. 2003. Life history traits of the invader Dikerogammarus villosus (Crustacea: Amphipoda) in the Moselle River, France. International Review of Hydrobiologie (In press.)
Dick, J. T. A., and Platvoet, D. 2000. Invading predatory crustacean Dikerogammarus villosus eliminates both native and exotic species. Proceedings of the Royal Society of London Biological Sciences 267(1447):977-983.
Dick, J. T. A., and Platvoet, D. 2001. Predicting future aquatic invaders; the case of Dikerogammarus villosus. Aquatic Nuisance Species Digest 4(3):25-27.
Musko, I. B. 1989. Amphipoda (Crustacea) in the littoral zone of Lake Balaton (Hungary). Qualitative and quantitative studies. Internationale Revue der gesamten Hydrobiologie 74(2):195-205.
Musko, I. B. 1994. Occurrence of Amphipoda in Hungary since 1853. Crustaceana 66(2):144-152.
Sporka, F. 1999. First record of Dikerogammarus villosus (Amphipoda, Gammaridae) and Jaera istri (Isopoda, Asselota) from the Slovak-Hungarian part of the Danube river. Biologia (Bratislava) 54(5):538.
Van den Brink, F. W. B., Van der Velde, G. and Bij de Vaate, A. 1991 Amphipod invasion on the Rhine. Nature 352:576
Van der Velde, G., Rajagopal, S., Kelleher, B., Muskó, I. B. and Bij de Vaate, A. 2000. Ecological impact of crustacean invaders: General considerations and examples from the Rhine River. Crustacean Issues 12:3-33.
Selective Pollination - Donald Forsha Jones (1928) Chapter 7
Guardian Unlimited - Pink Peril threatens native species in Britain’s rivers
NOAA, Great Lakes Environmental Research Laboratory
This report was prepared by Danielle M. Crosier and Daniel P. Molloy (New York State Museum) with assistance from Abraham bij de Vaate (Institute for Inland Water Management & Waste Water Treatment - The Netherlands) and Simon Devin (Université de Metz - France).