Non-indigenous Range Expansion of the Blue Catfish (Ictalurus
furcatus) in the Satilla River, Georgia
Timothy F. Bonvechio, Bryant R. Bowen, Jason S. Mitchell, and Justin Bythwood
Southeastern Naturalist, Volume 11, Issue 2 (2012): 355–358
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Non-indigenous Range Expansion of the Blue Catfish (Ictalurus
furcatus) in the Satilla River, Georgia
Timothy F. Bonvechio1,*, Bryant R. Bowen1, Jason S. Mitchell1, and Justin Bythwood1
Abstract - Here we present evidence of the first field observation of the nonnative Ictalurus furcatus
(Blue Catfish) occurring on the Satilla River, GA, in May 2011, and additional collections since
then. This is the second large, non-native riverine catfish to be found in the Satilla River basin.
Pylodictis olivaris (Flathead catfish) was first collected from the Satilla River in May 1996. The
ecological effects of Blue Catfish on native mussel and fish species in the Satilla River are currently
unknown, but competition with native catfishes is likely.
Ictalurus furcatus Lesueur (Blue Catfish) inhabit large rivers and major tributaries
associated with swift chutes and flowing waters around deep pools, as well as oxbow
lakes and reservoirs (Boschung and Mayden 2004, Jenkins and Burkhead 1994, Ross
2001). Although Blue Catfish are considered a freshwater species, they inhabit brackish
waters (Greenlee and Lim 2011, Schloesser et al. 2011) and can tolerate salinities up to
15 ppt (Christmas and Waller 1973, Dennison et al. 1993, Perry 1968, Ross 2001). Blue
Catfish are members of the North American bullhead catfish family, Ictaluridae, which is
the largest family of freshwater fishes endemic to North America (Nelson 1976, Page and
Burr 1991). I. furcatus and I. balsanus Jordan and Snyder (Balsas Catfish) comprise the
I. furcatus species group, which is the sister group to the I. punctatus Rafinesque (Channel
Catfish) clade (Lundberg 1992, Ross 2001). Distinguishing characteristics of the Blue
Catfish include the unique two-vessel swim bladder and a straight anal fin-ray margin,
with an anal fin-ray count ranging from 30 to 36 (Boschung and Mayden 2004, Etnier and
Starnes 1993, Jenkins and Burkhead 1994, Page and Burr 1991, Smith 1979).
The native range of the Blue Catfish in the United States includes the Mississippi,
Missouri, and Ohio river basins along coastal drainages of the Gulf of Mexico from the
Alabama River to the Rio Grande (Ross 2001). As a result of the Blue Catfish growing to
exceptionally large sizes, they have been widely introduced as a food and sport fish and
now occur in twenty-nine states throughout the Mississippi basin as well as the Atlantic,
Pacific, and Gulf coastal slopes (Fuller et al. 1999, Graham 1999). Other reasons for nonindigenous
occurrences include intentional stocking or unintentional flooding of private
waterbodies (Guier et al. 1984, Metee et al. 1996). In Georgia, Blue Catfish are native to
the Coosa River, but have been widely translocated to other river drainages (see http://
including the Altamaha, Chattahoochee, Flint, and Savannah (Bonvechio et al. 2011a,
Dahlberg and Scott 1971, Glodeck 1980, Homer and Jennings 2011, Straight et al. 2009).
Currently, the only river drainages in Georgia where the Blue Catfish has not been documented
include the Ochlockonee, St. Mary’s, and Suwannee.
A Blue Catfish (368 mm total length, 448 g) was captured on the Satilla River in
southeast Georgia, on 25 May 2011 (Fig. 1). The male Blue Catfish was captured as
part of the current Pylodictis olivaris Rafinesque (Flathead Catfish) removal program by
the Georgia Department of Natural Resources (GADNR; Bonvechio et al. 2011b). The
capture location (30°53.290'N, 81°50.696'W) was 22.5 km upstream of the US Highway
1Georgia Department of Natural Resources, PO Box 2089, Waycross, GA 31502-2089. *Corresponding
author - Tim.Bonvechio@dnr.state.ga.us.
Notes of the Southeastern Nat u ral ist, Issue 11/2, 2012
356 Southeastern Naturalist Vol. 11, No. 2
17 bridge near the town of Bullhead Bluff, GA. This is the first documented report of a
Blue Catfish existing in the Satilla River.
Unlike the Flathead, for which illegal angler introduction is highly likely (Bonvechio
et al. 2011b), it is believed that Blue Catfish migrated to the Satilla River down the intercoastal
waterway, roughly 35 km from the Altamaha River sound, during the most recent
high water period occurring in April 2009. Salinity measurements taken in the lower
Satilla River in 2009 ranged between 0.1–8.6 ppt, within tolerance limits (T. Bonvechio,
unpubl. data). The parental source of the Blue Catfish in the Altamaha River migrated
downstream through hydrological releases from Lakes Oconee and Sinclair (Homer and
Jennings 2011). The source of these original populations is unknown, but illegal stockings
by the public are suspected (Bonvechio et al. 2011a). Additionally, a total of seven
Blue Catfish were recovered from the Satilla River from May to October 2011, ranging
between 360–492 mm total length and 337–1044 g. Two anecdotal sightings of Blue
Catfish by GADNR staff were noted while electrofishing in June and August 2010, but
no samples were collected at that time.
Potential impacts by Blue Catfish on native fish and mussel species are unknown.
Omnivorous feeding habits have been described in the introduced Blue Catfish
population of the Altamaha River (Bonvechio et al. 2011a). Large Blue Catfish can
be piscivorous, similar to large Flathead Catfish; thus, there is some concern over
potential effects of Blue Catfish foraging on native fish species in the Satilla River
(Bonvechio et al. 2009, 2011a). Nonnative taxa may affect native taxa through direct
and indirect biotic interactions, including competition, predation, habitat alteration,
and hybridization (Fuller et al. 1999, Sakai et al. 2001, US Fish and Wildlife Service
1994). Homer and Jennings (2011) found shifts in the gillnet catch of Ameiurus
catus (L.) (White Catfish) to Blue Catfish in Lake Oconee, GA, and suggested that
competition by introduced Blue Catfish and Flathead Catfish could drive declines in
the abundance of native White Catfish. Similarly, White Catfish declines have also
been noted in Virginia tidal rivers after Blue Catfish introduction (Schloesser et al.
Figure 1. Picture of the first Ictalurus furcatus (Blue Catfish) (368 mm TL, 448 g) captured on the
Satilla River, GA. It was caught on 25 May 2011.
2012 Southeastern Naturalist Notes 357
2011). White catfish are found in high numbers in the tidal areas of the Satilla River.
Similar to other recently introduced Blue Catfish populations (Bonvechio et al. 2011a),
increased detections suggest establishment in the Satilla River. While Blue Catfish
numbers remain low, impacts would be difficult to detect or minimal. However, previous
works suggest that displacement and or declines of native species, particularly
other native catfishes such as the White Catfish, may be expected.
Acknowledgments. This project was funded by the Georgia Department of Natural
Resources Wildlife Resources Division and State Wildlife Grant T-49-R.
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