Channa marulius (Hamilton, 1822)
Bullseye Snakehead

After Munro, 1955

After Hamilton, 1822; juvenile

Original description: Ophiocephalus marulius Hamilton, 1822:65, 367, pl. 17, fig. 19. An account of the fishes found in the river Ganges and its branches. Edinburgh and London, i-vii + 1-405, pls. 1-39. Type locality: “Gangetic provinces,” India. No types known.

Synonyms: Ophicephalus sowara Cuvier, 1831:426.
                   Ophicephalus grandinosus Cuvier, 1831:434.
                   Ophiocephalus leucopunctatus Sykes, 1839:158.
                   Ophiocephalus theophrasti Valenciennes, 1840:pl. 13, figs. 1-1a.
                   Ophicephalus pseudomarulius Gunther, 1861:478.
                   Ophiocephalus aurolineatus Day, 1870:99.
                   Channa marulius ara Deraniyagala, 1945:24, pl. 24.

Common names: bullseye snakehead; giant snakehead; great snakehead; cobra snakehead; Indian snakehead; soal (Pakistan); haal (Assam, India); sal, gajal (West Bengal, India); pumurl, bhor (Bijar, India); kubrah, sawal, dowlah (Punjab, India); saal (Orissa, India); poomeenu, phoola-chapa, phool-mural (Andra Pradesh, India); aviri, puveral (Tamil Nadu, India); chaeru-veraal, curuva, bral (Kerala, India); hoovina-murl, madinji, aviu (Karnataka, India); ara, gangara, kalumaha (Sinhalese, Sri Lanka); iru viral (Tamil, Sri Lanka); ara (Sri Lanka); trey raws (Cambodia).

         Smith (1945) noted that near Bankok, Thailand, the common name pla chon ngu hao is used for this species; ngu hao means cobra. Talwar and Jhingran (1992) listed a common name of kubrah, used in Punjab, India. This perhaps explains the use of “cobra snakehead” for this species in the U.S. aquarium fish trade.

         Native range: Pakistan (Kabul and Indus Rivers; Mirza, 1999); many drainages of India, Sri Lanka, Bangladesh, southern Nepal (Gandaki, Koshi, and Karnali River basins), Myanmar, Thailand, Mekong basin of Laos and Cambodia, and southern China (Day, 1877, Nichols, 1943; Mendis and Fernando, 1962; Qureshi, 1965; Fernando and Indrassna, 1969; Pethiyagoda, 1991; Talwar and Jhingran, 1992; Rainboth, 1996; Kottelat, 2001a). Smith (1945) cited this species as “one of the rarest of the serpent-heads found in Thailand.” It is not reported from Malaysia or Indonesia where it appears to be replaced by a somewhat lookalike species, Channa marulioides. Nichols (1943) recorded the species from the Yangtze drainage, China. Maurice Kottelat and Tyson Roberts (personal commun. to J.D. Williams, 2001) indicated that C. marulius, as currently recognized, is possibly a species complex.

         Introduced range: Introduced into residential lakes and adjoining canals in Tamarac, Broward County, Florida, and established as a reproducing population (Florida Fish and Wildlife Conservation Commission, 2001; Howells and others, 2002; Paul L. Shafland, personal commun., 2002).

Adult Channa marulius guarding young. Photographed April 23, 2003, in Tamarac, Broward County, Florida, by Ianar T. Sevi.

Channa marulius, from Khao Laem Reservoir, Kanchanaburi Province, Thailand, June 2002. Photo courtesy of Jean-Francois Helias, Fishing Adventures Thailand.

         Size: This species is reported to be the largest of the family Channidae, reaching a length of 120-122 cm (Bardach and others, 1972; Talwar and Jhingran, 1992). Talwar and Jhingran (1992) reported that it grows to 180 cm and a weight of 30 kg in Maharashtra State, western India, noting that a length of 30 cm can be attained in 1 year. Rohan Pethiyagoda and Prachya Musikasinthorn (personal commun., 2002) stated they doubted that any snakehead would reach such a length and were unaware of any specimens of that size. Murugesan (1978) reported a maximum size of 52.8 cm at 8 months from fish stocked at an average length of 37 mm in a tank in Karnataka State, southwestern India, with lengths of 38.6 to 48 cm typical in 1 year. He recorded growth of 2.5 to 4 mm/day for the first 3 months and 0.8 to 1.3 mm/day thereafter, with an average growth rate of 7 cm/month. Johal and others (1983) reported that bullseye snakeheads grow faster than Channa argus, C. punctata, or C. striata, but also noted that growth decreases with increasing age, with the greatest increase in weight occurring during the second year. Their specimens were obtained from River Ghagger, Rajasthan State, northwestern India. Ahmad and others (1990) also reported decreasing growth rate with increasing age in specimens from River Kali in northern India. Wee (1982) cited C. marulius and C. micropeltes as the two fastest growing snakeheads.

         Habitat preference: Lakes and rivers; deep, clear water with sand or rocky substrate (Talwar and Jhingran, 1992); “rivers usually in the vicinity of mud or fine sands” (Sen, 1985); “deep pools in rivers and occasionally in lakes” (Pethiyagoda, 1991). Jhingran (1984) noted presence of this species in swamps, tanks (=small reservoirs), and ponds, but that it also “prefers deep, clear stretches of water with sandy or rocky bottom.” Rainboth (1996) listed preferred habitat as “sluggish or standing water in canals, lakes, and swamps from India to China, south to Thailand and Cambodia.” He added that it is often found with submerged aquatic vegetation.

         Temperature range: No specific information in literature. Native range of the species is from about 34^o N to 7^o N, indicating a species that can exist in temperate to tropical conditions. Preliminary temperature testing on individuals from the established southeastern Florida population indicated the lower range to be about 10 ^oC (Paul L. Shafland, personal commun., 2002), suggesting that this population did not originate from northern reaches of the native range of this species.

         Reproductive habits: Breder and Rosen (1966) summarized brood size from Chacko and Kuriyan (1947) as being about 500 young with parents guarding them until they reached about 10 cm in length. Eggs are pale red-yellow and 2 mm in diameter, hatch in 54 hrs at 16-26 ^oC and 30 hrs at 28-33 ^oC. Parameswaran and Murugesan (1976a) reported brood sizes of 357 to over 3,600 in swamps in Karnataka State, India. Talwar and Jhingran (1992) remarked that this species lays eggs in a nest and guards them, and that breeding occurs through most of the year. Day (1875) supported this guarding habit by stating, “Colonel Puckle observes that they are very savage, protecting their young with great boldness.” Pethiyagoda (1991) noted that males are territorial. In river basins of southern Nepal, it is said to spawn from June until August (Shrestha, 1990). Parameswaran and Murugesan (1976a) indicated spawning occurs in all but the months of December and January in Karnataka State, India, peaking during the rainy season. Jhingran (1984) stated that fecundity of this species is “2,000-40,000 ova.” Mirza and Bhatti (1993) indicated a spawning period in Pakistan of April to June with parental protection of eggs and larvae for 6 weeks. Sriramlu (1979) reported two spawning periods (May-June and November-December) for Channa marulius in Andhra Pradesh, southeastern India, at altitudes ranging from 548 to 670 m above sea level. Srivastava (1980) also reported two spawning peaks (May and January) for this species from a lake at Gorakhpur, in Uttar Pradesh, northern India. This species is one of three snakeheads known to spawn in the absence of vascular aquatic plants (Parameswaran and Murugesan, 1976b).

A Mozambique tilapia (Oreochromis mossambicus), an introduced species in Thailand, bitten in half by a giant snakehead (Channa micropeltes). Photo courtesy of Jean-Francois Helias, Fishing Adventures Thailand.

         Food preferences: Regarded as predacious (Jhingran, 1984; Talwar and Jhingran, 1992), especially on other fishes (Schmidt, 2001). The few aquaristoriented websites that list this species warn that it cannot coexist in aquaria with other fishes once a length of 25 cm is reached. Schmidt (2001) goes further to recommend that two individuals of the same species or mixed with others should not remain in the same aquarium after they reach 25 cm, concluding that "at that stage ... they will establish a species aquarium in their own way." He described the species as a "thrust predator", noting that it is rarely found in the aquarium trade and, if found, individuals are juveniles.

         Dasgupta (2000) reported stomach contents of Channa marulius collected from several localities in West Bengal, India, as consisting primarily of fishes (40 percent), followed by crustaceans (30 percent), “macrophyte tissue” (15 percent), larval insects (10 percent), and algae (5 percent). Ahmad and others (1990) stated the diet of C. marulius in the River Kali, northern India, was more than 60 percent fishes and the remainder crustaceans, gastropods, insects, and larval chironomids.

         Characters: No patch of scales on gular region of head. Dorsal fin rays 45-55; anal fin rays 28-36; pectoral rays 16-18; pelvic fin rays 6. Lateral line scales 60-70; predorsal scales 16. Lateral line scales drop two rows between the 16^th and 18^th perforated scale. Scale rows between posterior margin of orbit and preopercular angle 10. Scales on top of head moderatesized with a rosette of head scales between the orbits, with the frontal head scale in the center of the rosette; two scales between rosette and the basal head scale; 10 scale rows between preopercular angle and posterior border of orbit. Pectoral fin length about half head length. Mouth large, lower jaw with 7 to 18 canines behind a single row of villiform teeth that widen to 5-6 rows at jaw symphysis. Teeth present on prevomer but absent on palatines (Talwar and Jhingran, 1992), and Smith (1945) indicated that canine teeth were absent from both prevomer and palatines.

         Talwar and Jhingran (1992) provided information on life colors for both young and adults, commenting that there is a “pale-edged ocellus” toward the upperside of the caudal fin base that “fades with growth,” but provided no information as to size when that happens. Kottelat (2001a), however, stated that the ocellus occurs only in individuals less than 40 cm in standard length. Juveniles often with a series of dark blotches (usually five) bordered posteriorly and posterodorsally by a series of white scales forming a white margin to the blotches (Prachya Musikasinthorn, personal commun., 2002).

         The only other species of Channa having an ocellus on the upper lobe of the caudal fin near its base is C. marulioides. The geographic ranges of the two species do not overlap. In contrast to C. marulius, C. marulioides has 55-58 lateral line scales, 13-15 predorsal scales, and 5-7 preopercular scales. The lateral line drops abruptly between the 17^th and 20^th scale in C. marulioides, and there is a two row drop of the lateral line in C. marulius between the 16^th to 18^thscale. Juveniles of C. marulius may have a series of dark blotches along the sides, margined posteriorly and posterodorsally by a series of white scales; late juveniles and adults of C. marulioides also have a series of dark blotches on the sides, but the posterior and posterodorsal scales of these blotches are dark, usually black, and margined with white (Lee and Ng, 1991).

         Commercial importance in the United States: Other than occasional mention on aquarist-oriented websites and Schmidt's (2001) statement that "giant snakehead" are rare in the aquarium trade, we found that it was being marketed under the name cobra snakehead as an aquarium fish in the U.S. Aquarist-oriented chat rooms on the Internet suggest it may be second in popularity to Channa micropeltes. Its introduction into southeastern Florida may have resulted from an intentional release of aquarium fish by hobbyists. Nevertheless, we recently learned of its availability in live-food fish markets in New York City (Leo Smith, personal commun., 2002) and, therefore, cannot rule out the live-food fish trade as having been the source of this introduction. Nevertheless, its popularity as a game species in Thailand (http://www.fishingasia.com) may have prompted someone to illegally introduce this fish for sport purposes. Using a special permit from the FFWCC to import restricted and prohibited aquatic species, the USGS purchased a young bullseye snakehead from an aquarium fish dealer in Rhode Island in early 2002. In May 2002, law enforcement personnel of the California Department of Fish and Game confiscated a bullseye snakehead from an aquarium fish dealer in the Los Angeles area (Richard Feeney, personal commun. 2002).

         Commercial importance in native range: This species is considered an important food fish in India, and it is a significant component of the freshwater fishery in Andhra Pradesh State (Talwar and Jhingran, 1992). Rao and Durve (1989) reported this species as one of three snakeheads fished commercially in Lake Jaisamand, the oldest reservoir in India. Sriramlu (1979) listed this species and Channa striata as the most preferred fish in two regions of Andhra Pradesh, India. Bardach and others (1972) noted that it was under culture in India and Pakistan in ponds and ricefields, and irrigation wells that do not support other fishes. Wee (1982) listed the species as being reared in monoculture ponds in India where it is fed tilapia. Nevertheless, Mirza and Bhatti (1993) stated that this species is unsuitable for aquaculture in Pakistan because it is piscivorous. Rainboth (1996) noted that it is “marketed fresh and sometimes alive” in Cambodia. It is touted as an important sport species in Thailand (http://www.fishingasia.com).

         Environmental concerns: The native range of this species indicates a temperate to tropical species that, if introduced, has the potential to establish into southern states of the contiguous United States as well as Hawaii. This species is regarded as a predator, particularly on other fishes (Schmidt, 2001). That it has become established as a reproducing population in southeastern Florida indicates the likelihood that it could establish elsewhere if introduced into areas with a suitable temperature regime.

         Comments: The diploid number of chromosomes of Channa marulius is 44 (Donsakul and Magtoon, 1991).