Invasion

Invasion Description

1st definite introduced record: New Haven/CT/New Haven Harbor (1969, 'occurs in abundance on southern oysters which are planted here; whether it is naturalized is doubtful' Perkins 1871). Introduced from Barnegat Bay northwards with transplanted oysters, native in Chesapeake Bay and probably in Delaware Bay. Smith and Prime (1870) reported it from New York Harbor, as 'Alive, attached to oysters recently brought from the South, in all likelihood recently'. There are United States National Museum of Natural History specimens from Long Island Sound dated 1911 and 1934. But it apparently was not common later and not included in Jacobson and Emerson's (1961) book for the New York City area. In New Haven, it 'occurs in abundance on southern oysters which are planted here; whether it is naturalized is doubtful' (Perkins 1871). It was reported from Narragansett Bay (Dall 1889; Johnson 1915) and Cape Cod (Abbott 1974), probably also on or near transplanted oysters. Ischadium recurvum has few recent reports from the Northeast, but is locally common in brackish tributaries of Narragansett Bay (Sheldon Pratt 1997, 2000, personal communications).

Native records: 
Chesapeake Bay- It was not reported in early Maryland collections by Say (before 1822) or Conrad (before 1831) in MD and VA (Conrad 1831; Say 1858), and was not listed by Dall (1889) for VA. The oldest dated United States National Museum of Natural History specimen from Chesapeake Bay is 1886 from MD (United States National Museum of Natural History collections). However, it is widespread in mesohaline tributaries, and has been found in pre-Columbian archaeological excavations (Rick Torben, personal communication). A specimen from Delaware Bay (1934) is in United States National Museum of Natural History collections. It was described as 'at one time (1889) frequently collected above the Cohansy River; but is now very rare' (Maurer et al. 1974).

Geographic Extent

Ischadium recurvum is native in Chesapeake and probably Delaware Bays, and definitely introduced from Barnegat Bay to Cape Cod, with transplanted oysters.

Introduced Records: RI/Narragansett Bay (Dall 1889); Warren/RI/Kickamuit River, Narragansett Bay (Sheldon Pratt 1997, personal communication, established); South Kingstown-Narragansett/RI/Pettaquamscutt River (Sheldon Pratt 2000, personal communication, established); New Haven/CT/New Haven Harbor (Perkins 1871); Norwalk Point/CT/Long Island Sound (1911, USNM 225304); CT-NY/Long Island Sound (1934, USNM 407179); NY/New York Harbor (Smith and Prime 1870); Richmond (Staten Island)/NY/Princes Bay, New York Harbor (undated, ANSP 55683, Academy of Natural Sciences of Philadelphia 2007); Point Pleasant/NJ/Manasquan Inlet (1900, ANSP 78959, Academy of Natural Sciences of Philadelphia 2007); Seaside Park/NJ/Barnegat Bay (1903, ANSP 84747, Academy of Natural Sciences of Philadelphia 2007); NJ/Barnegat Bay (Richards 1938). Barnegat Bay - Richards (1938) described I. recurvum as  'abundant from Chesapeake Bay southward; local in NJ and southern New England; probably introduced into Barnegat Bay with seed oysters from the Chesapeake'. However, it is not included on more recent faunal lists (Loveland and Shafto 1986; Loveland and Vaughlitois 1986).

Native range- DE-NJ/'above Cohansey River', Delaware Bay (1889, Maurer et al. 1974); DE-NJ/Delaware Bay (1934, USNM 407182); Hacketts Bar/MD/Annapolis Harbor, Severn River (1950, Allen 1960); Kent County/MD/mouth of Chester River (1995, Ruiz et al. unpublished data); Queen Anne County/MD/Chester River (1930, Academy of Natural Sciences of Philadelphia 2002); Cambridge/MD/Choptank River (Humphries et al. 1985); Calvert Cliffs/MD/Chesapeake Bay (Abbe 1987); Eagle Bridge-Solomons/MD/Patuxent River (Cory 1967); MD/Smiths Creek, Potomac River (1883, ANSP 110458, Academy of Natural Sciences of Philadelphia 2002); Point Lookout/MD/Potomac River-Chesapeake Bay (1886, USNM collections); 16-60 km from mouth/Rappahannock river (Davies 1972); Norfolk/VA/Hampton Roads (Calder 1966); Accokeek County/VA/Chincoteague Bay (1916, 1934, USNM collections, undated); MD-VA/Chincoteague Bay (1988, Counts and Bashore 1991); Northampton County/VA/probably Hog Island Bay (USNM collections, undated)