Ictalurus furcatus

History of Spread

Ictalurus furcatus (Blue Catfish) is native to Mississippi and Gulf of Mexico drainages north to PA and SD, south to the Gulf Coast (AL to Rio Grande TX-NM) (Page and Burr 1991). There have been more recent stockings on Atlantic Slope (VA, NC) and western states including CA, AZ (Lee et al. 1980; Page and Burr 1991; Fuller et al. 1999). It was introduced to the San Francisco Bay Delta by 1979 (Cohen and Carlton 1995).

Ictalurus furcatus was reported to have been introduced to the Potomac at the turn of the century by the United States Fish Commission (Smith 1907), as an accidental contaminant of stocks of I. punctatus (Channel Catfish). However, preserved voucher specimens, labelled as I. furctatus were actually I. punctatus (Burkhead et al. 1980), so these early reports are unverified.

In 1975, the Virginia Division of Inland Fish and Game (VDIFG) began a stocking program for I. furctatus in the James and Rappahannock estuaries (Jenkins and Burkhead 1993). VA populations are well-established, ahd sizes of record fishes increased through the 80's. Catches of large fish in the James and Rappahannock estuaries were mentioned in fishing columns of the Washington Post in the summers of 1995 and 1996. Since 1990, abundace of I. furctatus has fluctuated in VA rivers, but peak abundances have become successively larger (Greenlee and Lim 2011; Schloesser et al. 2011).

James River - I. furcatus was stocked in the estuary in 1975 (64, 100 fish), and has been rapidly increasing in abundance to the present (Jenkins and Burkhead 1995; Greenlee and Lim 2011; Schloesser et al. 2011).

VA/York-Pamunkey-Mattaponi Rivers- I. furcatus was first stocked in the Mattaponi River in 198r, and now occurs in the Pamunkey and York Rivers as well (1985, Greenlee and Lim 2011; Schloesser et al. 2011)

. Piankatank River- I. furcatus was first caught in the Piankatank River in 2000 (Schloesser et al. 2011)

Rappahannock River - I. furcatus was stocked in the estuary in 1974, 1975, 1977 (97,800 fish), and has been rapidly increasing in abundance to the present. In an extensive fish survey, in the 1980s, it was found in the tidal river; but not in nontidal sections (Maurakis et al. 1987).

Potomac River- Burke and Brittle Lakes in the drainage were stocked in 1981, 1983, and 1985. One adult fish was caught in 1987 in the Potomac at the mouth of the Anacostia, possibly a reservoir escape or a stray from the Rappahannock (Nammick and Fulton 1987). By 2002, I. furcatus was widespread, and increasing in abundance in the tidal freshwater Potomac (Starnes 2002). The catch of this fish has increased greatly, now about 30X 2002 levels (Maryland Department of Natural Resources 2010; Schloesser et al. 2011).

Other Chesapeake Tributaries- By 2008-2010, I. furcatus was reportedly caught, and apparently established in the fresh-oligohaline tidal regions of the Patuxent, Nanticoke, Sassafras, and Susquehanna Rivers (Maryland Department of Natural Resources 2010; Schloesser et al. 2011). . On August 3, 2011, a specimen was caught at Conowingo Dam (USGS Nonindigenous Aquatic Species Program 2011). Presumably, these range extensions resulted from a mixture of releases by fishermen and natural dispersal. The brackish waters of the bay have been less of a barrier than biologists had expected. Blue catfish have been caught at salinities as high as 15 ppt (Schloesser et al. 2011)

Invasion Comments