The Mexican hornshark (''Heterodontus mexicanus'') is a

bullhead shark The bullhead sharks are members of the genus ''Heterodontus'', the only members of the family Heterodontidae and only living members of the order Heterodontiformes. All are relatively small, with the largest species reaching just in maximum le ...

of the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Heterodontidae. This shark is grey-brown in color, with black spots scattered on the fins and body. It has a cylindrical trunk, conical head, and small spiracles behind the eyes. The snout of the Mexican hornshark is very round and blunt. Like all members of the order Heterodontiformes, this shark has fin spines in front of both of its dorsal fins. The first dorsal fin originates before the pectoral fins, while the second dorsal fin originates behind the pelvic fins. The Mexican hornshark reaches a maximum length around 70 cm, but usually reaches between 50 and 60 cm on average. Young hornsharks hatch around 14 cm.

Habitat and range

Mexican hornsharks are distributed throughout the coast of the Eastern Pacific, mainly around southern Baja California, and possibly as far south as Peru. The rocky bottoms, coral reefs, and sandy areas of the

littoral zone The littoral zone, also called litoral or nearshore, is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely flood ...

create the habitat of this hornshark. The Mexican hornshark can be found at a maximum depth of 50 m, but is usually found down to 20 m.

Behavior

Like all members of the order Heterodontiformes, the Mexican hornshark is

oviparous Oviparous animals are animals that reproduce by depositing fertilized zygotes outside the body (i.e., by laying or spawning) in metabolically independent incubation organs known as eggs, which nurture the embryo into moving offsprings kno ...

. After an unknown gestation period, the female attaches an unknown number of spiral-shaped egg cases to rocks on the sea floor. The length of the incubation period of these egg cases is also unknown. Not much about the feeding habits of the Mexican hornshark is known, but it most likely feeds on shelled invertebrates. Because of its size, this shark poses no danger to humans.

Conservation

The Mexican hornshark is listed as least concern by the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...

. This shark is not considered to have commercial value, but it is at risk nonetheless because it is taken as bycatch by fishing operations that use bottom gillnets. Mexican hornsharks caught as bycatch are either discarded or used in

fishmeal Fish meal (sometimes spelled fishmeal) is a commercial product made from whole wild-caught fish, bycatch, and fish by-products to feed farm animals, such as pigs, poultry, and farmed fish.R. D. Miles and F. A. Chapman.FA122: The Benefits of Fish ...

. If released back into the water, these sharks are hardy enough to survive, but unfortunately many discarded hornsharks are left on beaches to die. Overall, the threat to Mexican hornsharks is considerable, as their range is restricted and they are frequently caught.

References

External links

{{DEFAULTSORT:Mexican Hornshark Heterodontidae Fish of Mexican Pacific coast Fish described in 1972