Horn Shark - Distribution and Habitat

Distribution and Habitat

The horn shark inhabits the continental shelf of the eastern Pacific Ocean, occurring off the coasts of California and Baja California from Monterey Bay southward, and in the Gulf of California. Uncommon influxes of warm water northward may bring it as far as San Francisco Bay. There are unconfirmed reports of this species off Ecuador and Peru, which may be misidentifications of other species.

For most of the year, horn sharks are most common at a depth of 2–11 m (6.6–36 ft). At the onset of winter, they migrate to water deeper than 30 m (98 ft). This species has been found in caves as deep as 200 m (660 ft). Juvenile horn sharks between 35–48 cm (1.15–1.57 ft) long prefer sandy flats with low vertical relief, in water 40–150 m (130–490 ft) deep. They often take advantage of large feeding pits excavated by the bat ray (Myliobatis californica) for shelter and food. As they mature, horn sharks shift into shallower water and their preferred habitat becomes structurally complex rocky reefs or algae beds. This strongly benthic species seldom ventures more than 2 m (6.6 ft) above the substrate.

The relative abundances of the horn shark and the swellshark (Centroscyllim ventriosum), which shares the same habitat, are negatively correlated, because horn sharks favor water over 20 °C (70°F) while swellsharks are more tolerant of cold. At Santa Catalina Island, a 20-year warming trend has resulted in an increase in the horn shark population and a decrease in the swellshark population. Horn sharks are less common than swellsharks in the northern Channel Islands, where the water is cooler.