No study has yet quantified the impacts of Rhithropanopeus harrisii, but anecdotal reports in the scientific literature indicate that it can alter food webs, compete with and potentially displace native crabs, crayfish, as well as benthophagous fishes (reviewed in Roche and Torchin 2007). In the Caspian Sea, where it has reached very high densities, the crab is responsible for fouling water intake pipes and causes economic loss to fishermen by spoiling fishes in gill nets (Zaitsev and Öztürk 2001). In Texas, the crab has become very abundant in almost freshwater reservoirs and is reported to foul PVC intakes in lakeside homes and clog the cooling system of a nuclear powerplant in Glenrose (Keith, 2006; Hildebrand, pers. comm..). Payen and Bonami (1979) also identified R. harrisii as a carrier of the white spot baculovirus, which causes disease in penaeid prawn species and the blue crab (Callinectes sapidus).
Location Specific Impacts:
Aral Sea (Asia)
Competition: Rhithropanopeus harrisii is thought to compete with endemic benthic fishes and invertebrates (Aladin & Potts, 1992).
Competition: Rhithropanopeus harrisii larvae were reported to dominate local zoobenthos in the Dead Vistula, Poland (Grabowski et al., 2005).
Texas (United States (USA))
Competition: There is some evidence that Rhithropanopeus harrisii may have displaced a native crayfish in Texan lakes (Keith, 2006).
Fouling: Rhithropanopeus harrisii has caused fouling problems by clogging the PVC intakes in lake homes in Texas. It has also been found blocking intakes pipes at a nuclear power plant in Glen Rose (Perry, 2007; Keith, 2006).