The Beautiful Blue Catfish
Blue catfish (Ictalurus furcatus) are members of the bullhead catfish family, native to the drainages of the Mississippi, Missouri, and Ohio river basins and the Gulf of Mexico. Because of their popularity as game fish, this species has also been introduced to freshwater systems throughout North and South America, and is considered invasive in these areas.
Like many catfish, I. furcatus is a bottom dweller. They can often be found near complex structures such as rocky outcroppings, fallen trees, or sunken structures that provide both food and shelter. The blue catfish is an opportunistic predator, consuming any fish or aquatic invertebrates it can find, as well as eggs, small amphibians, and injured or recently deceased animals. Adult I. furcatus are seldom prey for other species due to their size, but hatchlings and juveniles are often food for cormorants, willets, osprey, pelicans, and bald eagles. To deter predators, this species has serrated barbs along their dorsal and pectoral fins, each laced with a particularly painful toxin.
Though they can be difficult prey for other animals, the blue catfish is a popular target for fishermen, and for good reason; they're the largest species of catfish in North America. Adults can easily reach a length of 65 in (170 cm) and a weight of 165 lb (75 kg). As indicated by their name, most individuals are grey or blue, with a lighter underbelly. This species also lacks scales, a common characteristic of catfish, and the face is framed by long whisker-like barbels that help it detect nearby food.
While generally solitary, blue catfish aren't territorial, and tend to ignore each other until the mating season. Reproduction begins in April and continues until June, during which time males attract a female by building a nest and releasing attractive pheromones. Once a female has selected a male, she lays between 4,000-8,000 eggs per kilogram of bodyweight in his nest (i.e. if the female weighs 2 kg, she may lay between 8,000-16,000 eggs). The male then disperses sperm over the eggs. Following fertilization, the male chases away the female and guards the nest for about a week, at which time the eggs hatch. The hatchlings, also known as fry, stay close together in schools for several weeks before growing large enough to disperse. It will take them a further 5 years for them to reach maturity; on average individuals live about 10 years, but can live as long as 25.
Conservation status: The blue catfish is considered Least Concern by the IUCN. Within its native range, populations face minor threats from dams and droughts. Where it has been introduced, the species is considered invasive due to its voracious appetite.
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Photos
Missouri Department of Conservation
NOAA
Earl Nottingham
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