SRAC Publication No. 180 Southern Regional Aquaculture Center December, 1988 . Channel Catfish Life History and Biology Thomas L. Wellborn* Channel cattish, Ictalurus punctatus Rocky Mountains. Since then chan- is located on the back between the (Rafinesque), is the most important nel catfish have been widely intro- dorsal and caudal fins (Fig. 1). One species of aquatic animal commer- duced throughout the United States conspicuous characteristic of all cially cultured in the United States. and the world. catfish is the presence of barbels It belongs to the family Ictaluridae, around the mouth. The barbels are order Siluriformes. Members of the Physical characteristics arranged in a definite pattern with order Siluriformes are found in fresh Like all native North American cat- four under the jaw and one on each and salt water worldwide. There are fishes, a channel catfish has a body tip of the maxilla (upper jaw). at least 39 species of catfish in North that is cylindrical in cross-section, America, but only six have been cul- and lacks scales. Fins are soft-rayed The channel catfish is the only tured or have potential for commer- except for the dorsal and pectoral spotted North American catfish with cial production. They are the blue fins which have sharp, hard spines a deeply forked tail. There are 24-29 catfish, Ictalurus furcatus (LeSueur); that can inflict a nasty, painful rays in the anal fin. They are general- the white catfish, Ictalurus catus wound if a catfish is handled care- ly olivaceous to blue on the back, (Linnaeus); the black bullhead, Ic- lessly. An adipose fin (lacking rays) shading to the off-white ventrally. talurus melas (Rafinesque); the brown bullhead, Ictalurus nebulosus (LeSueur); the yellow bullhead, Ic- talurus natalis (LeSueur); and the flathead catfish, Pylodictis olivaris (Rafinesque). Distribution Channel catfish were originally found only in the Gulf States and the Mississippi Valley north to the prairie provinces of Canada and Mexico, but were not found in the Atlantic coastal plain or west of the * University of Florida. Fig. 1. External parts of the Channel Catfish. Texas Agricultural Extension Service ● Zerle L. Carpenter, Director ● The Texas A&M University System ● College Station, Texas Their color, to a large extent, is dic- for channel catfish larger than 18 in- In production ponds the mouth rate tated by the color of the water they ches total length, and in natural of channel catfish is determined by inhabit. In clear water they may ap- waters fish may constitute as much water temperature; length of time pear almost black, while in muddy as 75 percent of their diet. held at different water temperatures; water they may be a light yellow. quantity and quality of food fed; Young channel catfish are irregular- Channel catfish primarily detect palatability, or taste of food; frequen- ly spotted on their sides, but the food with their sense of taste. Taste cy of feeding; water quality, etc. spots tend to disappear in the adults. buds are found over the entire exter- Most farm-raised catfish are har- nal surface of catfish as well as in- vested at a weight of 11/4 pounds at Habitat side the mouth, pharynx and gill an age of about 18 months. In natural waters channel catfish live arches. They are most numerous on in moderate to swiftly flowing the barbels and gill arches. In clear Water quality streams, but they are also abundant water, eyesight can be an important Water quality preferences and limita- in large reservoirs, lakes, ponds and means of finding food. However, in tions for wild channel catfish are not some sluggish streams. They are turbid water, taste is the primary way any different from those of farm- usually found where bottoms are catfish locate food. The organ of raised channel catfish. The lethal sand, gravel or rubble, in preference smell (olfactory organs) may play oxygen level for both wild and farm- to mud bottoms. They are seldom some role, but this has not been well raised catfish is about 1.0 ppm, and found in dense aquatic weeds. Chan- established. The olfactory organs are reduced growth occurs at oxygen found in the nostrils (nares) which nel catfish are freshwater fish but concentrations of less than 4 ppm. they can thrive in brackish water. are located on top of the head just in Channel catfish, in natural waters, front of the eyes. are no more tolerant of high levels of Channel catfish generally prefer ammonia and nitrites than are farm- clear water streams, but are common Age and growth raised catfish, but are seldom ex- and do well in muddy water. During Channel catfish grow best in warm posed to lethal concentrations of the day they are usually found in water with optimum growth occur- either ammonia or nitrite. deep holes wherever the protection ring at temperatures of about 85° F of logs and rocks can be found. Most (29.4° C). With each 18° F (10° C) Respiration movement and feeding activity oc- change in temperature there is a Like other animals, channel catfish curs at night just after sunset and doubling or halving of their metabo- need oxygen to live. They use oxygen just before sunrise. Young channel lic rate. This means that within for energy production and to help catfish frequently feed in shallow rif- limits, their appetite increases with build all the various parts of the fle areas while the adults seem to increasing water temperatures or body. However, oxygen is at most feed in deeper water immediately decreases with decreasing water only about 25 percent as abundant in downstream from sand bars. Adults temperatures. water as in the air. To get oxygen, rarely move much from one area to fish must expend more energy than another and are rather sedentary, In natural waters, the average size air-breathers. Fortunately, fish have while young fish tend to move about channel catfish caught by fishermen well developed breathing organs, the much more extensively, particularly is probably less than 2 to 3 pounds, gills. Although catfish live in the at night when feeding. but the world record of 58 pounds water, gills serve essentially the same was caught in Santee Cooper Reser- functions as our lungs--to take Feeding voir, South Carolina, in 1964. The oxygen from the external environ- Feeding can occur during day or size and age that channel catfish ment and to rid the body of toxic night, and they will eat a wide variety reach in natural waters depends on gaseous waste, carbon dioxide many factors. Age and growth of both plant and animal material. (CO2). Water passes over the gill Channel catfish usually feed near the studies have shown that in many surface where oxygen diffuses into bottom in natural waters but will natural waters channel catfish do not the blood and carbon dioxide dif- take some food from the surface. reach 1 pound in size until they are 2 fuses out. Based on stomach analysis, young to 4 years old. One study in the Lake catfish feed primarily on aquatic in- of the Ozarks, Missouri, found that The gills of channel catfish are sects. The adults have a much more channel catfish did not reach a size located on each side of the head varied diet which includes insects, of 13 inches total length until they (Fig. 2) and they are covered by a snails, crawfish, green algae, aquatic were 8 years old. The maximum age protective movable flap of skin plants, seeds and small fish. When ever recorded for channel catfish is called the gill flap or operculum. available, they will feed avidly on ter- 40 years, whereas most commercially There are four gills on both sides of restrial insects, and there are even raised catfish are harvested before the head, each consisting of a double records of birds being eaten. Fish be- they are 2 years old. row of slender gill filaments. come an important part of the diet A fish breathes by sucking water in Similarly, if the oxygen concentra- through the mouth where it flows tion in the water is low, a fish has to directly over the gill filaments and breathe faster if it is to meet all of its across the lamellae. Blood chan- oxygen requirements. During normal neled through the heart has a low respiration only about 60 percent of oxygen concentration, but at the gi1l the gill surface is used for gas ex- lamellae surface it passes near water change. During increased respir- high in oxygen. By simple diffusion, atory demands, up to 100 percent of oxygen crosses the gill surface and the gill surface may be used. enters the blood where it is carried throughout the fish. Respiration of It is easy to see that any alteration in this type is called counter-current Fig. 2. Schematic drawing of fish gill structure or function can be exchange. Simple diffusion of oxygen dangerous to catfish. Any increase in gills. through the gill lamellae and into the the thickness of the gill lamellae will These filaments are supported by a blood occurs because the gill lamel- decrease the efficiency of gas dif- flexible white gill arch. Each side of lae are extremely thin. fusion. If the gills become swollen or the filament has many thin, small puffy oxygen and carbon dioxide cross plates called lamellae. It is Carbon dioxide is released from fish transfer are decreased. Gills can be- across the gill lamellae that the im- in much the same way oxygen is come thickened following exposure portant respiratory gases are ex- taken in--by counter-current ex- to ammonia, certain vitamin deficien- changed (Fig.