Description
Potentially Misidentified Species- Ictalurus furcatus is easily confused with grey unspotted specimens of I. punctatus, but can be distinguished by the anal fin shape (Jenkins and Burkhead 1993).
Taxonomy
Kingdom | Phylum | Class | Order | Family | Genus |
---|---|---|---|---|---|
Animalia | Chordata | Osteichthyes | Siluriformes | Ictaluridae | Ictalurus |
Synonyms
Invasion History
Chesapeake Bay Status
First Record | Population | Range | Introduction | Residency | Source Region | Native Region | Vectors |
---|---|---|---|---|---|---|---|
1974 | Established | Expanding | Introduced | Regular Resident | North America | North America | Fisheries(Fisheries Intentional) |
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
Ecology
Environmental Tolerances
For Survival | For Reproduction | |||
---|---|---|---|---|
Minimum | Maximum | Minimum | Maximum | |
Temperature (ºC) | 21.0 | |||
Salinity (‰) | 0.0 | 12.0 | 0.0 | 2.0 |
Oxygen | hypoxic | |||
pH | ||||
Salinity Range | fresh-meso |
Age and Growth
Male | Female | |
---|---|---|
Minimum Adult Size (mm) | 400.0 | 400.0 |
Typical Adult Size (mm) | 700.0 | 700.0 |
Maximum Adult Size (mm) | 1397.0 | 1397.0 |
Maximum Longevity (yrs) | 22.0 | 22.0 |
Typical Longevity (yrs | 9.0 | 9.0 |
Reproduction
Start | Peak | End | |
---|---|---|---|
Reproductive Season | |||
Typical Number of Young Per Reproductive Event |
|||
Sexuality Mode(s) | |||
Mode(s) of Asexual Reproduction |
|||
Fertilization Type(s) | |||
More than One Reproduction Event per Year |
|||
Reproductive Startegy | |||
Egg/Seed Form |
Impacts
Economic Impacts in Chesapeake Bay
Ictalurus furcatus (Blue Catfish) is a popular new sport and commercial species, as one of VA's largest fishes (Jenkins and Burkhead 1993). In the spring and summer of 1995, and 1996, catches of large fish in the James and Rappahannock were frequently mentioned in the Washington Post. As populations increased in the Potomac, captures of record fish captured attention among local fishermen. There was uncertainty in the Maryland Department of Natural Resources as to whether recognizing record catched woukd encourage illegal intorductions of this invasive fish (Thomsen 2010). As a new top predator, it may be reducing abundance of other fishes, particularly shads, migratory herrings (Alosa spp.), and menhaden (MacAvoy et al. 2000; Schloesser et al. 2011). Potentially, I. furcatus and the other introduced giant, Pylodictis olivaris (Flathead Catfish), may be interfering with attempts to restore American Shad (Alosa sapidissima) (Garman et al. 2010; Groves and Love 2010). Management of Blue Catfish is complicated by need to balance the recreational fishery with the need to protect native fish stocks. Commericial fishery has limited potential to control I. furcatus populations, because of high levels of chemical contamination in adult dish (Schloesser et al. 2011).
References- Jenkins and Burkhead 1993; MacAvoy et al. 2000
Economic Impacts Outside of Chesapeake Bay
Ictalurus furcatus (Blue Catfish) is a highly valued food and sport fish. It has been stocked in recent decades on the Atlantic Slope (VA, NC) and western states including CA, NV (Lee et al. 1980; Page and Burr 1991). It has been introduced to at least 16 states outside its native range (Fuller et al. 1999).
The introduction of I. furcatus to the Cape Fear River NC, apparently had little effect on fish community structure or fisheries (Guier et al. 1981) despite its size and predatory habits. From a purely economic and sports point of view,I. furcatus could be regarded as a beneficial introduction, but its effects on native fish communities have not been well studied.
References - Fuller et al. 1999; Guier et al. 1981; Jenkins and Burkhead 1993; Lee et al. 1980; Page and Burr 1991; Thomas 1993
Ecological Impacts on Chesapeake Native Species
Impacts of the introduction of Ictalurus furcatus (Blue Catfish) in the James and Rappahannock Rivers are substantial and increasing (Schloesser et al. 2011).
Competition - Competition with native Ameiurus catus (White Catifsh), I. nebulosus (Brown Bullhead), and I. natalis (Yellow Bullhead)(especially involving juvenileI. furcatus) is likely, but hasn't been documented to our knowledge However, Maryland fisheries surveys in the Potomac suggest a decrease in abundance of A. catus (Groves and Love 2010), probably resulting from both competition and predation.
Predation - Ictalurus furcatus (Blue Catfish) are likely to be important predators, given their size and piscivorous food habits (Carlander 1969; Jenkins and Burkhead 1993). Statistical analyses indicate that I. furcatus has adversely affected clupeid (herring- family fishes) populations in the James and Rappahannock Rivers (Austin 1998, personal communication). Gut and isotope analyses indicate that anadromous Alosa spp. (Shad, Alewives, Blueback Herring) form a substantial fraction of I. furcatus' diet, resulting in a strong marine signature in the isotope composition of the freshwater predator (MacAvoy et al. 2000). Feeding studies indicate that younger fish in the James, York, and Rappahannock Rivers (smaller than 300 mm) feed mostly on benthic invertebrates, but that larger fishes (300-600mm) feed mostly on fishes. Menhaden (Brevoortia tyrannus) was the most frequent prey species (Schloesser et al. 2011).
References- Austin 1998, personal communication; Carlander 1969; Jenkins and Burkhead 1993; MacAvoy et al. 2000
Ecological Impacts on Other Chesapeake Non-Native Species
Impacts of the introduction of Ictalurus furcatus (Blue Catfish) in the James and Rappahannock Rivers are being studied (Austin 1998 personal communication; Garman 1998 personal communication). The large size, predatory habits, and rapid increase in abundance of this fish (Jenkins and Burkhead 1993) mean that it could have significant impacts on introduced biota.
Competition - Competition with introduced Ictalurus punctatus (Channel Catfish) and Pylodictus olivaris (Flathead Catfish) is possible but has not been documented to our knowledge. However, Maryland fisheries surveys in the Potomac suggest a decerease in abundance of I punctatus (Maryland Department of Natural Resources 2010), probably resulting from both competition and predation.
Predation - Ictalurus furcatus is reported to feed on Corbicula fluminea (Asian Freshwater Clam) (Jenkins and Burkhead 1993), which motivated its introduction to CA. However, this catfish had no noticeable effect on clam abundance (Cohen and Carlton 1995). Ictalurus furcatus is probably an important predator on introduced centrarchids (Sunfishes).
References - Austin 1998 personal communication; Cohen and Carlton 1995; Garman 1998 personal communication; Jenkins and Burkhead 1993
References
Allen, Kenneth O.; Avault, James W. (1971) Notes on the relative salinity tolerance of channel and blue catfish, Progressive Fish-Culturist 33: 135-137Burkhead, Noel M.; Jenkins, Robert E.; Maurakis, Eugene G. (1980) New records, distribution, and diagnostic characters of Virginia ictalurid catfishes with an adnexed adipose fin, Brimleyana 4: 75-91
Carlander, Kenneth D. (1969) Handbook of freshwater fishery biology. Vol. 1., In: (Eds.) . , Ames. Pp.
Cohen, Andrew N.; Carlton, James T. (1995) Nonindigenous aquatic species in a United States estuary: a case study of the biological invasions of the San Francisco Bay and Delta, , Washington DC, Silver Spring MD.. Pp.
Fuller, Pam. L.; Nico, Leo; Williams, J. D. (1999) Nonindigenous fishes introduced into inland waters of the United States, , Bethesda MD. Pp.
2010 Status of Flathead Catfish in Chesapeake Bay rivers. PowerPoint presentation, archive.chesapeakebay.net/.../49012_12-01-10_Presentation_4_11059.pdf
Greenlee, Bob (2011) Tidal river Blue Catfish, None , Richmond VA. Pp. 1-6
2010 Tidal Blue Catfish in Maryland waters. Powerpoint Presentation archive.chesapeakebay.net/.../49012_120110_Presentation_5_11059.pdf
Guier, C. R.; Nichols, L. E.; Rachels, R. T. (1981) Biological investigation of flathead catfish in the Cape Fear River, Proceedings of the Annual Conference of the Southeast Association of Fish and Wildlife Agencies 35: 607-621
Jenkins, Robert E.; Burkhead, Noel M. (1993) Freshwater fishes of Virginia., , Bethesda, MD. Pp.
Lee, David S.; Gilbert, Carter R.; Hocutt, Charles H.; Jenkins, Robert E.; McAllister, Don E.; Stauffer, Jay R. (1980) Atlas of North American Freshwater Fishes, , Raleigh. Pp.
MacAvoy, S. E.; Macko, S. A.; McIninch, S. P. (2000) Marine nutrient contributions to freshwater apex predators., Oecologia 122: 568-573
Maurakis, Eugene; Woolcott, William S.; Jenkins, Robert E. (1987) Physiographic analyses of the longitudinal distribution of fishes in the Rappahannock River, Virginia, ASB Bulletin 34: 1-14
Nammick, Marta F.; Fulton, Jean M. (1987) A blue catfish, Ictalurus furcatus, from the Potomac River, The Maryland Naturalist 31: 58
Page, Lawrence M.; Burr, Brooks M. (1991) Freshwater Fishes., , Boston. Pp.
Perry, W. G. (1973) Notes on the spawning of blue and channel catfish in brackish water ponds, Progressive Fish-Culturist 35: 164-166
Schloesser, Ryan W. and 6 authors (2011) Ecological role of Blue Catfish in Chesapeake Bay communities and implications for management, American Fisheries Society Symposium 77: 369-382
Smith, Hugh M. (1907) Our fish immigrants, National Geographic 18: 385-400
Starnes, Wayne C. (2002) Current diversity, historical analysis, and biotic integrity of fishes in the lower Potomac basin in the vicinity of Plummers Island, MD, Proceedings of the Biological Society of Washington 115: 273-320
Thomas, Matthew E. (1993) Monitoring the effects of introduced flathead catfish on sportfish populations in the Altmaha River, Georgia, Proceedings of the Annual Conference of the Southeast Association of Fish and Wildlife Agencies 47: 531-538
Thomson, Candus (8/15/2010) Blue catfish unvelcome in Md.- except in contests, Baltimore Sun None: Sports-4
Thomson, Candus (9/27/2010) Blue cafish given a reprieve, Baltimore Sun None: None