Heterodontus francisci 


Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Chondrichthyes Heterodontiformes Heterodontidae

Scientific Name: Heterodontus francisci
Species Authority: (Girard, 1855)
Common Name(s):
English Horn Shark, Bullhead Shark, Horned Shark, California Horn Shark, Port Jackson Shark
French Requin Dormeur Cornu
Spanish Dormilón Cornudo
Heterodontus californicus Herald, 1961
Taxonomic Source(s): Eschmeyer, W.N. and Fricke, R. (eds). 2015. Catalog of Fishes: genera, species, references. Updated 1 October 2015. Available at: (Accessed: 1 October 2015).
Taxonomic Notes: The literature suggests that this species may also occur off the coasts of Ecuador and Peru, but these records are unconfirmed and may have been misidentifications of another species.

Assessment Information [top]

Red List Category & Criteria: Data Deficient ver 3.1
Year Published: 2015
Date Assessed: 2014-03-06
Assessor(s): Carlisle, A.B.
Reviewer(s): Jew, M.L. & Nehmens, M.C.
Contributor(s): Freedman, R.M. & Lowe, C.G
Facilitator/Compiler(s): Lawson, J., Walls, R.H.L., Dulvy, N.K. & Ebert, D.A.
Horn Shark (Heterodontus francisci) is a benthic shark, endemic to the warm temperate to subtropical waters on the Pacific continental shelf off Mexico and the United States. The species has also been reported off Ecuador and Peru, however, these reports are unconfirmed. This bullhead shark species occurs from the intertidal zone to a depth of 152 m, although it is most common at 2-11 m, moving offshore in the winter to waters >30 m. The species exhibits a high degree of segregation corresponding to its life history, with adults occurring shallower than juveniles. Horn sharks have a small home range and exhibit long term site fidelity. They are of no commercial value, although they are taken as bycatch primarily off Mexico. They are hardy and have low post-release mortality, however, catches should be monitored if the gillnet fishery in Mexico expands significantly in the future. Insufficient information is available at present to assess Horn Shark beyond Data Deficient. In the United States this species could well be Least Concern as it is commonly encountered by divers but is extremely rare in capture fisheries and has no apparent threats.
Previously published Red List assessments:
2006 Data Deficient (DD)
2000 Lower Risk/least concern (LR/lc)

Geographic Range [top]

Range Description: In the United States, Horn Shark is most common off the coast of southern California, but it ranges to Monterey Bay and may occasionally be found as far north as San Francisco Bay (where it is not resident) during influxes of warm water (Compagno 2001). In Mexico, it occurs off Baja California, in the Gulf of California and slightly further south.
Countries occurrence:
Mexico; United States (California)
FAO Marine Fishing Areas:
Present - origin uncertain:
Atlantic – southeast; Atlantic – eastern central
Lower depth limit (metres): 152
Upper depth limit (metres): 2
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: There is little to no information available on meta-population structure, population health and population status for this bullhead shark species. It is considered rare in central and northern California. Horn Shark occurs year-round in San Ignacio Lagoon, Mexico with lower abundance in summer and fall (Segura-Zarzosa et al. 1997). Differences in egg case morphology between the Channel Islands, California and the mainland suggest that there may be separate populations in southern California (Ebert 2003).
Current Population Trend: Unknown
Additional data:

Habitat and Ecology [top]

Habitat and Ecology: The Horn Shark is a common, small, warm temperate to subtropical benthic endemic shark. It is found on the continental shelf from the intertidal zone out, to a depth of 152 m, although it is most common at a depth of 2-11 m. During the winter, this species migrates into deeper waters, usually below 30 m. They exhibit a high degree of segregation corresponding to their life history. Adolescent sharks (between 35 to 48 cm) tend to remain in deeper water, usually between 40-150 m, and as they mature they migrate back into relatively shallow water. This segregation of habitat by size and stage of maturity reduces competition for food and habitat between younger and older sharks. Habitat also changes ontogenetically, with juveniles inhabiting sandy bottoms with little vertical relief and adults inhabiting rocky reefs with caves and crevices, or areas of thick algae cover. Juveniles use Bat Ray (Myliobatis californica) feeding pits in sandy areas as shelter and foraging areas. Adults that occur in the algal habitat have noticeably longer fin spines than those in the reef habitat. This is due to their spines being worn down by going in and out of caves. Horn Shark shows distinct diel patterns of activity, controlled by light intensity. Adults are relatively inactive diurnally, but are very active nocturnally. They are site-specific, returning to the same resting place at dawn and remaining there until the evening. They have a small home range, usually no larger than 1,000 m², and they exhibit long-term site fidelity as sharks have been recovered in their tagging locations after up to 11.25 years at liberty. The furthest distance a Horn Shark has been documented travelling is 16.3 km. Water temperature is an important factor controlling the relative abundance of Horn Shark, as they prefer water over 70°F (21°C) (Roedel and Ripley 1950, Nelson and Johnson 1970, Feder et al. 1974, Finstad and Nelson 1975, Strong 1989, Ebert 2003).

Horn Shark are oviparous, and females lay two eggs every 11-14 days usually between February and April, depositing up to 24 eggs in a single breeding season (Ebert 2003). Egg cases are usually laid in shallow water between 2 and 13 m deep. Development of embryos lasts 6-10 months, depending on water temperature (Dempster and Herald 1961, Ebert 2003). Size at birth is 15-17 cm total length (TL) (Compagno et al. 1995, Ebert 2003). Males mature at 56 to 61 cm TL (Strong 1989) and reach a maximum length of 83 cm TL (Roedel and Ripley 1950, Feder et al. 1974), while females over 58 cm TL are mature (Compagno et al. 1995), with a maximum length of 96 cm TL, but possibly up to 120 cm TL (Roedel and Ripley 1950, Feder et al. 1974). Growth rates are generally slow and very variable, and they do not correspond to size. The unconfirmed maximum age is 25 years (Eschmeyer et al. 1983, Michael 1993).
Systems: Marine

Use and Trade [top]

Use and Trade: Horn Sharks are captured as bycatch and large individuals are retained for human consumption. They have also been captured by divers for sport and for the large fin spines, which are made into jewellery. They are also used for display in public aquaria in the United States. In Mexico these sharks are probably used (or historically used) for fishmeal.

Threats [top]

Major Threat(s): In California, Horn Sharks are of no commercial value. They are taken as bycatch in traps and trawls and occasionally by recreational anglers. In Mexico they are caught as a bycatch of the shrimp fishery and other bottom-trawling operations. In the northern Gulf of Mexico and likely on the Pacific side of Baja California they are caught as bycatch in the demersal gillnet fishery during the winter and spring. This species should be closely monitored in Mexico if the gillnet fishery expands, as bycatch levels could impact the Mexican population (Wade Smith, pers comm). These sharks are kept in many public aquaria in the United States as they are hardy, attractive, readily maintained, and will breed in captivity (Compagno 2001, Ebert 2003).

Conservation Actions [top]

Conservation Actions: Like other bullhead sharks, Horn Shark is a hardy species that has high post-release mortality in drift and trawl nets. Individuals should be returned to the water if alive after capture (Walker 2005). Further information on distribution, population structure and biology is required.

Citation: Carlisle, A.B. 2015. Heterodontus francisci. The IUCN Red List of Threatened Species 2015: e.T39333A80671300. . Downloaded on 29 November 2015.
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