Blue Catfish, Ictalurus furcatus

Blue Catfish, Ictalurus punctatus. Fish caught in the Cooper River, South Carolina, March 2011. Length: 28 cm (11 inches). Catch, photograph and identification courtesy of Eli (obsessiveangling.wordpress.com).

Blue Catfish, Ictalurus punctatus. Fish caught in the Pearl River, Jackson, Mississippi, July 2019. Length: 30 cm (12 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.

Blue Catfish, Ictalurus punctatus. Fish caught from the banks of the Potomac River, Arlington, Virginia, March 2013. Length: 56 cm (22 inches). Weight: 1.8 kg (4 lbs 0 oz). Catch, photograph, and identification courtesy of Kenneth Tse, Toronto, Ontario, Canada.

Blue Catfish, Ictalurus punctatus. Fish caught in the Cooper River, South Carolina, March 2011. Length: 96 cm (3 feet 2 inches). Catch, photograph, and identification courtesy of Josh Leisen (joshadventures.com), Gaylord, Michigan.

The Blue Catfish, Ictalurus furcatus, is a member of the North American Catfish or Ictaluridae Family, and is known in Mexico as bagre azul. Globally, there are fifty-one species in the Ictaluridae Family, which have been placed in seven genera and include blue catfish, bullheads, channel catfish, and madtoms. The Ictaluridae Family is the largest freshwater family endemic to North America. There are ten species in the genus Ictalurus, all of which are found in the freshwater systems of Mexico.

The Blue Catfish has an elongated thick body that is compressed posteriorly. They have a dorsal hump near the center of their back which has earned them the nickname “humpback blue.” They are slate blue-gray in color and transition to white ventrally. Their head is wide when viewed from above and has small eyes and an inferior mouth that is equipped with small teeth in villiform bands with a protruding lower jaw with 4 pairs of black sensory barbels, 4 on the chin, 2 on the snout, and 1 on each corner of the mouth. Their anal fin has 30 to 36 rays with a long base and a flat margin; their caudal fin is deeply forked; they have a single dorsal fin which has 6 rays followed by an adipose fin; their pectoral fins have 8 to 10 rays; their pelvic fins have 8 rays. They have 14 to 21 gill rakers. They have smooth skin and no scales. Unlike the Channel Catfish they are not sexually dimorphic.

The Blue Catfish are generally found as solitary individuals in the deep areas of main channels and backwaters of medium to large rivers and large lakes at depths up to 15 m (49 feet), residing on the bottom during daylight hours and moving to swifter waters at night to feed. They have the ability to tolerate low levels of saline and wide ranges of climates. They are migratory and travel to warmer water temperature during the winter and cooler waters during the summer and to find ideal reproduction sites. The Blue Catfish is the largest North American Catfish, measuring a maximum of 1.65 m (5 feet 5 inches) in length and 68 kg (150 lbs) in weight. As of January 1, 2023, the International Game Fish Association world record stood at 64.9 kg (143 lbs 0 oz) with the fish caught in a lake in Virginia in June 2011. The Blue Catfish are opportunistic bottom predators possessing a keen sense of smell, sight and touch and that consume a wide variety of fish, crayfish, frogs, freshwater mussels and underwater vegetation, and they do practice cannibalism. The juveniles feed only at night and consume zooplankton and small aquatic insects. In turn they are preyed upon by various larger fish, otters, and a variety of sea birds. They rely heavily on a spinal toxin-containing barb located on both their dorsal and pectoral fins for defense. Reproduction is oviparous and monogamous with each female depositing up to 4,000 to 8,000 eggs per kg of body weight under logs and riverbanks; these eggs are then fertilized and guarded by the males until they hatch in six to ten days and for another two weeks until they disperse. Males exclude females to avoid cannibalization of their eggs. They grow rapidly in the first year. Blue catfish have a well-developed system for communication based on the release of chemical pheromones and sensory organs. They have life spans of twenty-five years.

The Blue Catfish can be easily confused with the Channel Catfish, Ictalurus punctatus (25 to 29 anal fin rays; spotting on the sides).

The Blue Catfish is a resident of Mexico’s freshwater systems being found in all rivers of the Atlantic Slope that drain into the Gulf of Mexico and the Caribbean.

From a conservation perspective the Blue Catfish is currently considered to be of Least Concern with stable, widely distributed populations. Their populations have been significantly negatively impacted by the construction of dams on some rivers. In other areas they have become a highly invasive pest. The Blue Catfish is heavily pursued throughout their range by recreation anglers. They are considered to be an excellent food fish.