Monocorophium acherusicum

History of Spread

Monocorophium acherusicum, an epifaunal tube-building amphipod, has been so widely dispersed by shipping that its original range is unknown. 'However, the eastern North Atlantic, from which it was originally described, seems the most probable source region' (Bousfield and Hoover 1997). However, Chapman (2000) considers M. acherusicum to be native to the Northwest Atlantic, and introduced to the coast of Europe. This amphipod was originally described from Italy by Costa in 1851 and was subsequently collected from southern Europe, the Atlantic coasts of France and Holland, and West Africa (Senegal) (Crawford 1937). [It may have been described from the Atlantic Coast of the U.S. by Say in 1818 (Say 1818), but the identity of his 'Podocerus cylindricus' is uncertain (Shoemaker 1934; Bousfield and Hoover 1997)]. By 1937, Monocorophium acherusicum had also been collected from the Suez Canal, East Africa, the Falkland Islands, Hong Kong, and New Zealand (Crawford 1937; Shoemaker 1934), and later from Australia (Fearn-Wannan 1968); Hawaii (Shoemaker 1947) and Japan (Onbe 1966). 'It is noteworthy that its present known distribution traces out some of the major shipping routes ...' (Hurley 1954). This species has been collected from ship fouling in England (Crawford 1937) and Hong Kong (Shoemaker 1947), and is abundantly found on wharves, pilings, buoys, etc. (Crawford 1937; Lincoln 1979). In the eastern Pacific, M. acherusicum was collected as early as 1905 in Yaquina Bay Oregon and now ranges from British Columbia to Baja California (Cohen and Carlton 1995).

In the western Atlantic, the date of first record is uncertain because of taxonomic confusion. If Say's (1818) 'Podocerus cylindricus' was identical with Smith and Verrill's 'Corophium cylindricum' (Smith and Verrill 1873), and most or all of these specimens were M. acherusicum, as asserted by Shoemaker (1934), then M. acherusicum may have been present on the Atlantic coast of North America (Little Egg Harbor, NJ) before 1818. Smith and Verrill's 'C. cylindricum' may have been either M. acherusicum (Shoemaker 1934) or M. insidiosum (Bousfield and Hoover 1997). We've chosen 1873 as the date of first record, since specimens of 'C. cylindricum' from Smith and Verrill's (1873) Martha's Vineyard survey probably were deposited in the National Museum and identified by Shoemaker (1934) as C. acherusicum. However, some of these specimens may have been M. insidiosum, described by Crawford in 1937 (Shoemaker 1947). Most of the specimens of M. acherusicum examined by Shoemaker are no longer in the catalogs of the United States National Museum of Natural History, and so cannot be checked.

We regard the Monocorphium acherusicum in the western Atlantic as cryptogenic. Its widespread introduction by shipping elsewhere in the world suggests that it could have been transported from the coast of Europe. If so, it became widely established long before it could be accurately identified and its movements tracked. By 1934 it ranged from at least as far north as New England to Brazil (Shoemaker 1934). [Shoemaker gives the northern limit as 'Baffins Bay', but Bousfield (1973) reported it as found north only to central ME.]

Shoemaker identified 'Corophium cylindricum' from one cruise in lower Chesapeake Bay (May, 1920), collected between Cape Charles City and New Point Comfort (Cowles 1930). These were probably C. acherusicum, which was found in that area by Feeley and Wass (1971). However, no specific mention of Chesapeake specimens was made in Shoemaker's later papers (1934; 1947). The oldest definitely identified specimen in the United States National Museum of Natural History catalog is dated 1958 from Norfolk VA.

Chesapeake Bay records are summarized below:

Adjacent Coastal Waters - Monocorophium acherusicum was abundant in Indian River and Rehoboth Bays, just north of our study area (Maurer 1977; Watling and Maurer 1972), and was reported as common in Atlantic coastal bays [from Rehoboth Bay DE to northern Chincoteague Bay (MD)], north of the mouth of the Chesapeake, but was absent in dead-end canals in areas developed for housing (Maxted et al. 1997). It was collected on pilings at Wachapreague Inlet VA (Feeley and Wass 1991).

Lower Chesapeake Bay - Monocorphium acherusicum was probably collected as 'Corophium cylindricum' in 1920 (see above). It was reported as common by Wass (1963), but Feeley and Wass (1971) found it scarce in the Bay proper, with only two collections, one from Middle Ground in the lower James and one from the pilings of the Chesapeake Bay bridge-tunnel. However, it was apparently common at some sites in Hampton Roads (Boesch, cited by Feeley and Wass 1971) and the lower York River (Marsh 1973). This amphipod was collected from fouling plates in summer of 1995 in Lynnhaven Bay, Gloucester Point, Norfolk, Mobjack Bay (Ruiz et al. unpublished data).

History References - Bousfield 1973; Bousfield and Hoover 1997; Cohen and Carlton 1995; Chapman 2000; Cowles 1930; Crawford 1937; Fearn-Wannan 1968; Feeley and Wass 1971; Hurley 1954; Lincoln 1979; Marsh 1973; Maurer 1977; Maxted et al. 1997; Onbe 1966; Ruiz et al. unpublished data; Say 1818; Shoemaker 1934; Shoemaker 1947;Verrill and Smith 1873; United States National Museum of Natural History collections; Wass 1963; Watling and Maurer 1972

Invasion Comments