The flathead catfish (Pylodictis olivaris), also called the motley, yellow cat, opelousas, bashaw, or shovelhead cat, is a large species of North American freshwater catfish. It is the only species of the genus Pylodictis. Ranging from the lower Great Lakes region to northernMexico, they have been widely introduced and are an invasive species in some areas. The closest living relative of the flathead is the widemouth blindcat, Satan eurystomus.
Their native range includes a broad area west of the Appalachian Mountains encompassing large rivers of the Mississippi, Missouri, and Ohio basins. The range extends as far north as Canada, as far west as Arizona, and south to the Gulf of Mexico including northeastern Mexico. Flatheads cannot live in full strength seawater (which is about 35 parts per thousand or about 35 grams of salt per liter of water), but they can survive 10 parts per thousand for a while and thrive up to about 5 ppt.
Flatheads grow to a length of 155 cm (61 in) and may weigh up to 56 kg (123 lb), making it the second largest North American catfish (after the blue catfish, Ictalurus furcatus). The average length is about 25-46 inches (64-117 cm). Their maximum recorded lifespan is 24 years. Males are mature from 16 cm (6.3 in) and 4 years of age while females mature from 18 cm (7.1 in) and 5 years of age, but may mature as late as 10 years. The world angling record flathead catfish was caught May 14, 1998, from Elk City Reservoir, Kansas, and weighed 123 lb 9 oz (56.0 kg).
Spawning occurs in late June and early July, the nests made in areas with submerged logs and other debris. The males, who also build the nests, fiercely and tirelessly defend and fan the clutch. The size of the clutch varies proportionately to the size of the female; an average of 2,640 eggs per kilogram of fish are laid.
The fry frequent shallow areas with rocky and sandy substrates where they feed on insects and worms such as annelids and polychaetes. Young flatheads are also cannibalistic, a fact which has largely precluded their presence in aquaculture.
Relationship with humans
Inhabiting deep pools, lakes, and large slow-moving rivers, flathead catfish are popular among anglers; their flesh is widely regarded as the tastiest of the catfishes. Their size also make the flatheads effective subjects of public aquaria.
Sport fishing for flathead catfish using either rod and reel, limb lines, or bare hands (noodling) and can be an exciting pastime. Anglers target this species in a variety of waterways including small rivers (barely large enough for a canoe), large rivers (such as the Missouri, Mississippi, Ohio, and Colorado Rivers), and reservoirs. A common element of flathead catfish location is submerged wood cover such as logs and rootwads which often collect at bends in rivers. A good flathead spot usually also includes relatively deep water compared to the rest of a particular section of river, a moderate amount of current, and access to plentiful baitfish such as river herring, shad, carp, drum, panfish, or suckers. Anglers targeting large flathead catfish usually use stout tackle such as medium-heavy or heavy action rods from 6–10 feet (1.8–3.0 m) in length with large line-capacity reels and line ranging from 20–80 pounds-force (89–356 N) test breaking strength. Generally large live baits are preferred such as river herring, shad, sunfish (such as bluegill), suckers, carp, goldfish, drum, and bullheads ranging from 5–12 inches (13–30 cm) in length. Sometimes nearly as much time and effort is spent catching baitfish ahead of time as is spent fishing for flatheads. While not as numerous as other catfish species, catching a large flathead catfish (over 20 pounds) usually makes the effort worthwhile to an avid catfisher. Flathead catfishing often takes place at night either from a boat or from shore once a catfisher has identified a likely looking flathead spot.
The blue catfish, Ictalurus furcatus, is the largest species of North American catfish, reaching a length of 165 cm (65 in) and a weight of 68 kg (150 lb). The average length is about 25-46 inches (64-117 cm). Blue catfish are distributed primarily in the Mississippi River drainage, including the Missouri, Ohio, Tennessee, and Arkansas Rivers. These large catfish have also been introduced in a number of reservoirs and rivers, notably the Santee Cooper lakes of Lake Marion and Lake Moultrie in South Carolina, the James River in Virginia, Powerton Lake in Pekin, Illinois, and Springfield Lake in Springfield, Illinois.
On June 18, 2011, Nick Anderson of Greenville, NC reeled in a 143-pound blue catfish. The fish was caught in John Kerr Reservoir, more commonly known as Buggs Island Lake, on the Virginia-North Carolina border. On June 22, 2011, the Virginia Dept of Game and Inland Fisheries certified the blue catfish as the state’s largest, setting a new state record. The fish had a length of 57 inches (145 cm) and a massive girth of 47 inches (120 cm).
On February 7, 2012, a 136-lb blue catfish was caught on a commercial fishing trot line in Lake Moultrie, more commonly known as Santee Cooper Lake, near Cross, South Carolina. It was 56 inches long. The fish is the largest blue catfish ever weighed on a certified scale in South Carolina, but it is not eligible for state record certification because it was not caught on a rod and reel.
On July 20, 2010, a yet to be certified new world record blue catfish was caught by Greg Bernal of Florissant, MO, on the Missouri River. Greg’s girlfriend, Janet Momphard, a nurse from St. Charles, helped land the world-record fish. The record catfish weighed in at 130 lbs. It was 57 inches long and 45 inches in girth. The previous angling world record, 124 lb, was caught by Tim Pruitt on May 22, 2005, in the Mississippi River. This record broke the previous blue catfish record of 121.5 Lbs caught from Lake Texoma, Texas.
The Indiana and Kentucky Record for a blue catfish was set in 1999 by Bruce Midkiff of Owensboro, Ky. The fish was caught in the tailwaters of the Cannelton dam in the Ohio River and weighed in at 104 pounds.
Blue catfish are opportunistic predators and will eat any species of fish they can catch, along with crawfish, freshwater mussels, frogs, and other readily available aquatic food sources; some blue catfish have reportedly attacked scuba divers in the Mississippi River. Catching their prey becomes all the more easy if it is already wounded or dead, and blue cats are noted for feeding beneath marauding schools of striped bass in open water in reservoirs or feeding on wounded baitfish that have been washed through dam spillways or power generation turbines.
Due to their opportunistic nature, blue catfish will usually take advantage of readily accessible food in a variety of situations, which from the angler’s perspective makes cut-up or dead baits, and even stink baits an excellent choice to target these fish. Blue cats will also respond well to live baits, with live river herring and shad usually a top choice, followed by large shiner minnows,sunfish, suckers, mullet], dead shrimp and carp. All of the above baits can be used as fresh cut baits with good success and freshwater drum also work well. Generally, a fairly large piece of cut bait (4-12 inches long) on a fairly large hook (3/0 to 9/0) is a good choice in rivers or reservoirs where large blue cats (50 lb and up) are a possibility. Depending on currents, sinkers ranging from 1/2 to 8 oz may be required, with 1-2 oz a good choice for many situations. To catch large blue catfish in rivers, the more current, the better usually, although fishing along current edges and breaks is often a good option. Blue catfish tend to favor deeper water in larger rivers and reservoirs, but will make feeding and spawning forays into relatively shallow water. Blue catfish can be frequently caught in warmer climates in water as shallow as 12 in. For the largest of specimens, fishing for them requires incredibly strong tackle; often fishermen targeting them will choose saltwater tackle such as a large, heavy-action pole with 100-lb-test line, and 10/0 circle hooks, with a 2-lb chunk of cut skipjack herring. Blue catfish are incredible fighters, and are often considered game fish due to their reputation for attacking anything from panfish baits to artificial bass lures.
Channel catfish, Ictalurus punctatus, is North America‘s most numerous catfish species. It is the official fish of Missouri, Iowa, Nebraska,Kansas, and Tennessee, and is informally referred to as a “channel cat”. In the United States, they are the most fished catfish species with approximately 8 million anglers targeting them per year. The popularity of channel catfish for food has contributed to the rapid growth ofaquaculture of this species in the United States.
Distribution and habitat
Channel catfish are native to the Nearctic, being well distributed in lower Canada and the eastern and northern United States, as well as parts of northern Mexico. They have also been introduced into some waters of landlocked Europe and parts of Malaysia and almost as many parts of Indonesia. They thrive in small and large rivers, reservoirs, natural lakes, and ponds. Channel “cats” are cavity nesters, meaning they lay their eggs in crevices, hollows, or debris, to protect them from swift currents. In Canada, the species is largely, though not exclusively, limited to the Great Lakes watershed from Lake Nipigon southward.
Channel catfish possess very keen senses of smell and taste.At the pits of their nostrils (nares) are very sensitive odor sensing organs with a very high concentration of olfactory receptors.In channel catfish, these organs are sensitive enough to detect several amino acids at about one part per 100 million in water. In addition, the channel catfish has taste buds distributed over the surface of its entire body.These buds are especially concentrated on the fish’s four pair of barbels(whiskers) surrounding the mouth — about 25 buds per square millimeter.This combination of exceptional senses of taste and smell allows the channel catfish to find food in dark, stained, or muddy water with relative ease.
Length and weight
A member of the Ictalurus genus of American catfishes, channel catfish have a top-end size of about 40–50 pounds (18–23 kg). The world record channel catfish weighed 58 pounds, and was taken from the Santee-Cooper Reservoir in South Carolina, on July 7, 1964. Realistically, a channel catfish over 20 lb (9 kg) is a spectacular specimen, and most catfish anglers view a 10-lb (4.5-kg) fish as a very admirable catch. Furthermore, the average size channel catfish an angler could expect to find in most waterways would be between two and four pounds.
Channel catfish will often coexist in the same waterways with its close relative, the blue catfish, which is somewhat less common, but tends to grow much larger (with several specimens confirmed to weigh above 100 lb).
As channel catfish grow longer, they increase in weight. The relationship between length and weight is not linear. The relationship between length (L, in cm) and weight (W, in kg) for nearly all species of fish can be expressed by an equation of the form:
Invariably, b is close to 3.0 for all species, is the length of a typical fish weighing 1 kg. For channel catfish, b = 3.2293, somewhat higher than for many common species, and cm.
Catfish have enhanced capabilities of taste perception, hence called the “swimming tongue”, due to the presence of taste buds all over the external body surface and inside the oropharyngeal cavity. Specifically, they have high sensitivity to amino acids, which explains their unique communication methods as explained below.The catfish has a facial taste system that is extremely responsive to L-alanine and L-arginine. More specifically, their facial taste system senses heightened levels of L-amino acids in freshwater. Feeding behavior to food is due to amino acids released by food. It is reported that this causes maxillary and mandibular barbell movements, which orient the catfish’s posture and food search. When the food stimulates the taste receptors, it causes more excitation which see as exaggerated biting, turning, or mastication.
The channel catfish is adapted to limited light conditions. Members of the genus Ictalurus, which inhabit muddy waters, do not depend solely on visual cues. Instead, they are known to rely heavily on chemotaxic cues. Sound production may be another important means of communication among channel catfish and other species living in turbid habitats.
The North American channel catfish is an ostariophysan, or a bony fish occupying a freshwater habitat. These fishes are known to produce club cells and alarm substances for communication purposes. Both the fish’s habitat and the presence of chemosensory cells covering the body are presumably the results of favored selection for this method of communication. Catfishes are capable of producing and recognizing individual specific pheromones. Through these pheromones, a catfish can identify not only the species and sex of aconspecific, but also its age, size, reproductive state, or hierarchical social status.
Territoriality in channel catfish is identifiable by a change in body odor, which is recognizable by other members of the same species. This chemical change in the amino acid composition of the skin mucus can be noted by chromatographic methods, and are not long-lasting; rather, they last only long enough to communicate to other fish in the vicinity. Changes may be the result of the release of the contents of the club cells. These cells do not open directly to the surface of the skin, but injury caused by fighting and other agonistic behaviors may release the cells’ contents. Since catfish have a dominance hierarchy system, information relative to the change of status of any fish is important in recognition of the social strata.
Distinction between a communication signal and an information signal
In the channel catfish, while a communication signal is directed toward the receiver and contains a specific message, an information signal is a part of the general existence of the individual or the group.For example, release of an alarm signal will communicate danger, but the individual’s recognition odor is only an information signal identifying one fish from another. With regards to the function and contents of the club cells, it is reasonable to suggest that the club cells serve different functions throughout the fish’s life cycle. Variation in the contents of the club cells’ information signals therefore may change with the species’ needs at different stages of life.
All species of catfishes can generate sound through stridulation, and many produce sounds through drumming. Stridulation consists of the clicking or grinding of bony parts on the fish’s pectoral fins and pectoral girdle, and drumming consists of the contraction of specialized sonic muscles with subsequent reverberation through the swimbladder. Variability in the sound signals created by the channel catfish depends on the mechanism by which the sound is produced, the function of the resultant sound, and physical factors such as sex, age, and temperature. This variation may result in increased complexity of the outgoing signal and may allow for increased usefulness of the signal in interspecies communication. In the channel catfish, sounds are produced only by pectoral stridulation, as this species does not express sonic muscles. However, the swimbladder may still be used to help with audition.
Due to the high density of water, sound travels 4.8 times faster and over longer distances underwater than in air. Consequently, sound production via stridulation is an excellent means of underwater communication for channel catfish. The pectoral spine of the channel catfish is an enlarged fin ray with a slightly modified base that forms a complex articulation with several bones of the pectoral girdle.Unlike the other pectoral fin rays, the individual fin segments of the spine are hypertrophied and fused, except for at the distal tip. The surface of the spine is often ornamented with a serrated edge and venomous tissues, designed to deter predators. Sounds produced during fin abduction result from the movement of the base of the pectoral spine across the pectoral girdle channel. Each sweep of sound consists of a number of discrete pulses created by the ridges lining the base of the pectoral spine as they pass over the rough surface of the girdle’s channel. The stridulation sounds are extremely variable due to the range and flexibility of motion in fin use. Different sounds may be used for different functions in communication, such as in behavior towards predators and in asserting dominance.
In many channel catfish, as in humans, individuals favor one fin or another for stridulatory sound production (in the same way as humans are right-handed or left-handed). The first ray of the channel catfish pectoral fin is a bilaterally symmetrical spinous structure that is minimally important for movement; however, it can be locked as a defensive adaptation or used as a means for sound production. According to one scholar, most fish tend to produce sound with their right fin, although sound production with the left fin has also been observed.
The inferior division of the inner ear, most prominently the utricle, is considered the primary area of hearing in most fishes. The hearing ability of the channel catfish is enhanced by the presence of the swimbladder.It is the main structure that reverberates the echo from other individuals’ sounds, as well as from sonar devices. The volume of the swimbladder changes if fish move vertically, and thus is also considered to be the site of pressure sensitivity. The latency of swimbladder adaptation after a change in pressure affects hearing and other possible swimbladder functions, presumably making audition more difficult. Nevertheless, the presence of the swimbladder and a relatively complex auditory apparatus allows the channel catfish to discern different sounds and tell from which directions sounds have come.
Communication to predators
Pectoral stridulation has been considered to be the main means of agonistic communication towards predators in channel catfish.Sudden, relatively loud sounds are used to startle predators in a manner analogous to the well-documented, visual flash display of various lepidopterans. In most catfish, a drumming sound can be produced for this use, and the incidences of the drumming sounds can reach up to 300 or 400 per second. However, the channel catfish must resort instead to stridulation sounds and pectoral spine display for predator avoidance. In addition to communication towards predators, stridulation can be seen as a possible alarm signal to other catfish, in the sense of warning nearby individuals that a predator is near.
Channel catfish are omnivores, and can be caught using a variety of natural and prepared baits, including crickets, nightcrawlers, minnows, shad, crawfish, frogs, bullheads, sunfish, andsuckers. Catfish have even been known to take Ivory soap as bait .
Juglines, trotlines, limb lines, and bank lines are popular methods of fishing for channel catfish in addition to traditional rod-and-reel fishing. Another method uses traps, either “slat traps” — long wooden traps with an angled entrance — and wire hoop traps. Typical bait for these traps include rotten cheese and dog food. Catches of as many as 100 fish a day are common in catfish traps. An unusual method practiced in the Southeastern United States is noodling – catching catfish by hand.
When removing the hook from a catfish, anglers should be mindful of the sharp spines on the pectoral and dorsal fins.
Catfishes (order Siluriformes) are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat‘s whiskers, catfish range in size and behavior from the heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores (species that eat dead material on the bottom), and even to a tiny parasitic species commonly called the candiru, Vandellia cirrhosa. There are armour-plated types and there are also naked types, neither having scales. Despite their name, not all catfish have prominent barbel. Members of the Siluriformes order are defined by features of the skull and swimbladder. Catfish are of considerable commercial importance; many of the larger species are farmed or fished for food. Many of the smaller species, particularly the genus Corydoras, are important in theaquarium hobby. Many catfish are nocturnal,but others (many Auchenipteridae) are crepuscular or diurnal (most Loricariidae or Callichthyidaefor example).