Author: Blainville, 1816
Field Marks:
These small sharks are easily recognizable, being the only living ones with dorsal fin spines and an anal fin. The piglike snout, small anterior mouth, enlarged molariform teeth in the back of the mouth, supraorbital ridges, rough skin, paddlelike paired fins, and enlarged first gill slits are characteristic of this genus.
Habitat, Distribution and Biology:
These are common, sluggish, warm-temperate and tropical bottom sharks of water above 21°C, mostly confined to the continental and insular shelves and uppermost slopes of the western and eastern Pacific and western Indian Ocean. They occur from the intertidal to 275 m depth, but most are in shallower water than 100 m. As far as is known, these are night-active sharks, slowly swimming and crawling on rocky, kelp-covered and sandy bottom. Some species at least favour rocky crevices and caves, where they spend the day resting. At least one species is migratory when adult, and returns to its breeding sites each year after long migrations.
These sharks are oviparous, producing eggs in unique, large, spiral-flanged egg cases. These are laid in specific 'nesting' sites in at least two species. Eggs may take over 5 months to hatch, and young hatch at a large size, over 14 cm.
Bullhead sharks primarily feed on benthic invertebrates. Sea urchins (echinoids) are a favorite food, but crabs, shrimps and other crustaceans, abalone, top shells and other marine gastropods, oysters, polychaetes and more rarely small fish are also eaten.
Several species of bullhead sharks have been kept in aquaria, where they have proved to be extremely hardy and can live for over a decade. Mating, egg-laying, hatching of eggs, and growth to maturity can occur in captivity.
Some bullhead sharks are often encountered by divers, who commonly harass them. Although regarded as harmless, these sharks can and do snap when provoked and occasionally pursue and bite their tormentors.
Interest to Fisheries:
These sharks are of minimal interest to fisheries, being caught as a byeatch of bottom trawl and line fisheries and utilized for human consumption and for fishmeal. They are commonly caught by divers and in sportsfisheries.