Gafftopsail Catfish, Bagre marinus
The Gafftopsail Catfish, Bagre marinus, whose common Spanish name is bagre bandera, is a member of the Sea Catfish or Ariidae Family, known collectively as bagres marinos in Mexico. Its common name stems from the fact that its extended first dorsal fin appears like a sail. Globally, there are four species in the genus Bagre, of which three are found in Mexican waters, one in the Atlantic and two in the Pacific.
The Gafftopsail Catfish have elongated and easily recognizable “catfish” bodies. Their color is steel-blue dorsally and transitions to silvery then to white ventrally. Their adipose fin is dark and their other fins are pale or dusky. Their head is arched and slightly flattened with a rounded snout and two pairs of closely set nostrils with the upper jaw forming a broad arc. Their teeth are on the roof of the mouth and found in four patches that from a narrow transverse arch. They have two pairs of barbels: one pair is elongated with long flat filaments at the corner of the mouth that reach the pelvic fins on the top jaw and the other pair is under the chin. They also have a longitudinal groove in a depression on the midline of the head. Their anal fin has a short base with 22 to 28 rays and a V-shaped indentation on the posterior margin; their caudal fin is deeply forked; their dorsal fin has a single serrated spine and seven rays, the first having extended white filaments that are equal to or greater than the length of the spine; their pectoral fins have a single serrated spine and 11 to 14 rays, the first having extended white filaments that are equal to or greater than the length of the spine; and their pelvic fins have six rays and are set well behind the dorsal fin. Their dorsal and pectoral fins each have a very sharp, toxic, slime-covered, barbed, and serrated spine. Females have larger pelvic fins than males. They have wide gill openings. Their lateral line is complete. They have no scales and their skin is smooth to the touch.
The Gafftopsail Catfish are found in shallow inshore waters, in brackish waters (including estuaries), and within mangrove-lined lagoons over sandy and muddy bottoms at depths up to 165 feet. They prefer water temperatures close to 25oC (77oF) but can be found in waters between 16oC (61oF) and 30oC (86oF). They migrate during the winter to deeper warmer waters and return to bays and estuaries for spawning during the early summer. They reach a maximum length of 1.0 meters (3 feet 3 inches) and weight of 4.5 kg (10 pounds). Unlike most catfish, which are primarily bottom feeders, they are opportunistic feeders and consume crustaceans (crabs, prawn, shrimp) and small fish throughout the water column. In turn they are preyed upon by bull sharks and tiger sharks. Reproduction is oviparous and involves the formation of dense spawning aggregations, which makes them sitting ducks for commercial fishermen. Females have low fecundity levels producing only 25 to 65 eggs annually, each measuring one-inch in diameter. Following fertilization, eggs are mouthbrooded by males for 60 to 80 days until hatching and for an additional two-week period in the larval stage until they reach four inches in length; males do not eat during the mouthbrooding period.
In Mexican waters the Gafftopsail Catfish are found in all waters of the Atlantic.
The Gafftopsail Catfish can be easily confused with the Hardhead Catfish, Ariopsis felis (lacks distinctive extensions of dorsal and pectoral fins).
The Gafftopsail Catfish are a common recreational catch throughout their range and are taken from bridges, piers, jetties, and surf utilizing a wide variety of natural and artificial baits. They are known for their strong fighting abilities and for their overabundant production of white slime. Most anglers consider them a nuisance trash fish. They are an important commercial fish in Mexican coastal communities along the Gulf of Mexico. They are a major component of the Tabasco, Tamaulipas, and Veracruz fisheries and economies where they are heavily fished and caught by small-scale artisanal fishermen utilizing gill nets, handlines, and traps and by illegal purse seine fishermen focusing on males during the breeding season. They are also taken in abundance as a by-catch of trawl fisheries in the states of Quintana Roo, Tamaulipas, and Yucatan. Catch levels from Mexican waters are on the order of 1,300 tons per year and they are marketed fresh. In other areas they are not pursued as they are considered trash fish. They are difficult to handle due to their venomous serrated dorsal and pectoral spines and require care in preparation, including the removal of their red lateral line to eliminate their “muddy” taste and make them palatable for human consumption. From a conservation perspective they are considered of Least Concern being widely distributed, common, and abundant with stable populations. They are unregulated throughout their range. In coastal Mexican waters of the Gulf of Mexico they are significantly overfished and have diminishing populations, thus should be considered Vulnerable.
Gafftopsail Catfish, Bagre marinus. Fish caught off the Sanibel Pier, Sanibel Island, Florida, April 2011. Length: 41 cm (16 inches). Catch, photo, and identification courtesy of Kenneth Tse, Toronto, Canada.