Invasion
Invasion Description
1st Record: Richmond/VA/James River (Cope 1869, Jenkins and Burkhead 1993(
Geographic Extent
Susquehanna River - Micropterus salmoides was probably introduced to the Susquehanna before 1893: 'widely introduced in Pennsylvania' (Bean 1893). Official USFC stocking began there in 1893 (Worth 1895). However, this fish was not listed for Susquehanna in PA by Fowler (1919; 1948). It is now common throughout the Susquehanna (Bielo 1963; McKeown 1984). Upper Bay- Micropterus salmoides was planted at Principio Creek in 1893, (Worth 1895) and the Severn, Gunpowder, Sassafras, Patapsco Rivers by United States Fish Commisionin 1901-1910 (Ravenel 1902; Bowers 1912). The first verified captures from the Upper Bay were in Elk and Bohemia Rivers (Fowler 1917; Radcliffe and Welsh 1917). It occurs regularly in the Rhode River (Hines et al.. unpublished data) and is widespread in upper Bay tributaries (Bush, Gunpowder, Northeast, Elk, Bohemia) (Fewlass 1980). In 1971-72, after heavy rains, including Hurricane 'Agnes', it was caught at Calvert Cliffs (Academy of Sciences of Philadelphia 1973), but was not collected there in subsequent (9) annual fish surveys (Horwitz 1987). Eastern Shore Tributaries - 'Black Bass' were introduced to the Tred Avon River, Easton MD (1901) and the Pocomoke River, Snow Hill MD in 1901-1907 (Ravenel 1902; Bowers 1911). Micropterus salmoides are now widespread in fresh and tidal fresh waters on the Eastern Shore in MD and VA (Lee et al. 1981; Jenkins and Burkhead 1993). Patuxent River- Micropterus salmoides was stocked by the USFC in 1897-1905 (Ravenel 1898; Bowers 1907), and is now common in fresh-oligohaline waters of the estuary (Jug Bay Wetlands Sactuary 1996; Mansueti 1950). Potomac River- The earliest Potomac specimen of M. salmoides was collected in 1876 (Bean and Weed 1911), and probably originated from unofficial stocking. It was introduced in Shenandoah River in 1889 and was later planted in the lower Potomac by the USFC . 'By 1896 the fish had become remarkably abundant in the vicinity of Washington' (Smith and Bean 1898). It is found from Chain Bridge to the Wicomico River and St. Clements Bay, but is more abundant in the tributaries (Lippson et al. 1979). Abundance of M. salmoides has greatly increased since the invasion of Hydrilla verticillata (Hydrilla) in the 1980s (Killgore et al. 1989; Phelps 1994; Kraus et al. 2012; de Mutsert et al. 2017). It is abundant above Chain Bridge to Great Falls, in the nontidal river (Starnes et al. 2011). Rappahannock River- M. salmoideswas probably introduced by unofficial stocking before 1876 (Jenkins and Burkhead 1993) or by United States Fish Commission (USFC) stocking in 1894 and 1897 (Bean 1896; Ravenel 1898), but the first verified record was in 1951 (Jenkins and Burkhead 1993). It was widespread in the upper, middle and lower (tidal fresh) river by 1983 (Maurakis et al. 1987). James River- Micropterus salmoides was considered to be possibly native, but probably introduced, to the James River (Jenkins and Burkhead 1993). The first verified record (with voucher specimens) was Cope's (1869) in Tuckahoe Creek, near Richmond VA. He mentions an earlier museum specimen, caught downriver in the James. Virginia Fish Commission reports from 1876 suggest it was introduced to James from SC around 1800, but no evidence was cited. (Jenkins and Burkhead 1993). It was not found in pre-European or 17th century archeaological sites in VA (Miller 1986).
Vectors
| Level | Vector |
|---|---|
| Probable | Fisheries Intentional |
Regional Impacts
| Ecological Impact | Predation | |
| Prey of Largemouth Bass in upper Chesapeake Bay included Gizzard Shad (Dorosoma cepedianum), Cyprinidae and Cyprinodontidae ('minnows'), Inland Silverside (Menidia beryllina), White Perch (Morone americana), Yellow Perch (Perca flavescens), and darters (Etheostoma) spp. (Fewlass 1980). 'The contents of 22 stomachs taken in brackish water consisted exclusively of fish remains. This fish is highly predatory; and where it is common, the destruction of minnows and smaller fish is great' (Hildebrand and Schroeder 1928). | ||
| Economic Impact | Fisheries | |
| Fisheries - Largemouth Bass (Micropterus salmoides) is a major sportfish in upper Chesapeake Bay and in all fresh-oligohaline tributaries of the Bay. Largemouth Bass were harvested commercially from Maryland tidal fresh and brackish waters of Chesapeake Bay until 1945, when it was designated a sportfish. Sportfishing pressure was initially low but intensified in the 1960's and 70's, resulting in lower abundances in MD tidewaters (Fewlass 1980). In the tidal Potomac, especially since the resurgence of submerged aquatic vegetation (SAV), and in other low-salinity regions, this fish attracts many fishers who make substantial investments in boats, tackle, and fishing tournaments. In 1998, 4 tournaments were held on tidal waters of the Bay (American Bass Association 1998). Similar bass tournaments on one location of the Hudson River generated $2.5 million/year (Mills et al. 1996a), so it is likely that Largemouth Bass contributes millions of dollars annually to local economies. | ||
| Ecological Impact | Competition | |
| Competition is possible between Largemouth Bass and Smallmouth Bass (M. dolomieu) which was probably introduced first to the Potomac. Smallmouth Bass rapidly colonized the Potomac down to Mount Vernon but soon became rare in tidal waters below Washington D.C. (Smith 1907). This range contraction coincides with the introduction of Largemouth Bass which rapidly became abundant in tidal waters (Smith and Bean 1898). Both species are largely piscivorous as adults, but M. salmoides appears to have a much greater preference still water, vegetation, and for estuarine conditions (Hildebrand and Schroeder 1928; Jenkins and Burkhead 1993; Page and Burr 1991). | ||