Invasion
Invasion Description
1st Record: VA/James River (1963, Pfitzenmeyer and Drobeck 1964)
Rangia cuneata was first collected in 1963 (found by Jon Shidler); in 'an excellent oyster settling area from which seed oysters have been transplanted to other regions of the Chesapeake Bay and upper tributaries of the Potomac River'. 'Great quantities about three-quarters of an inch in length are being caught in the mesh of haul seine nets' (Pfitzenmeyer and Drobeck 1964).
Geographic Extent
Havre de Grace/MD/Susquehanna Flats (Posey et al. 1993); Cecil County/MD/Sassafras River (Lippson 1979); Cecil County/MD/Northeast River (1967, Gallagher and Wells 1969); Thackeray Point/MD/Elk River (1968, Gallagher and Wells 1969); Kent County/MD/northernmost edge of mouth of Chester River (Lippson 1979); Crane Power Plant (Baltimore County)/MD/Seneca and Saltpeter Creeks (1978, Jordan and Sutton 1984); Smithsonian Environmental Research Center, Edgewater/MD/Rhode River (Lisppson 1973, Hines, Ruiz, Fofonoff, personal observations - scarce, prone to winter die-offs); Stafford County/VA/Potomac Creek, Potomac River tributary (1964, Pfitzenmeyer and Drobeck 1964); Riverside to Swan Point/MD/Potomac River (1964, Pfitzenmeyer and Drobeck 1964); Charles County/MD/Nanajemoy Creek (1964, Pfitzenmeyer and Drobeck 1964); Charles County/MD/Port Tobacco River (1964, Pfitzenmeyer and Drobeck 1964); VA/Rappahannock River (1964, Wass 1972, abundant by 1966-69 in the lower tidal-fresh oligohaline zone, between 30 and 40 mi. from the river mouth Davies 1972); VA/York River (established in the 1960s; Its range expanded downriver from river mile 20 to 10 and 15 after tropical storm 'Agnes', Boesch et al. 1976); VA/James River (1963, Pfitzenmeyer and Drobeck 1964); Point of Shoals-Horsehead Shoal/James River (1971, Larsen 1985); Hog Island/VA/James River (1972, Jordan and sutton 1984)
Vectors
| Level | Vector |
|---|---|
| Alternate | Ballast Water |
| Alternate | Oyster Accidental |
| Alternate | Canal |
Regional Impacts
| Ecological Impact | Food/Prey | |
| Rangia cuneata is important as a food resource for commercially important species [Callinectes sapidus (Blue Crab); Leiostomus xanthurus (Spot); Micropogonias undulatus (Atlantic Croaker); Pogonias cromis (Black Drum)] and for waterfowl (Cain 1972; Ebersole and Kennedy 1994). | ||
| Ecological Impact | Herbivory | |
| The invasion of Rangia cuneata into oligohaline parts of the Bay has resulted in large biomasses of suspension feeding bivalves where previously they were scarce. This has probably affected phytoplankton distribution and planktonic and benthic foodwebs in these regions, possibly in ways similar to those discussed by Phelps (1994) for Corbicula fluminea (Asian Freshwater Clam) in tidal fresh regions. However, the effects of R. cuneata, such as filtration, pseudofeces deposition, and other possible effects have not been well documented (R. Everett personal communication). Cerco and Noel (2010) estimated filtering rates for bivalves (Corbicula + Rangia in the oligohaline waters of Chesapeake Bay and its tributaries. Rangia comprised ~40-100% of the filter-feeding biomass in the major tributaries, being most abundant in the Potomac, but outweighed by Corbicula there. In the Rappahannock and Patuxent, it was the only significant bivalve filter-feeder, in biomass terms.The two species together removed 14% to 40% of the carbon load, 11% to 23% of the nitrogen load, and 37% to 84% of the phosphorus load from the water column (Cerco and Noel 2010). | ||