Leopard Houndshark, Leopard Shark.
Easily recognizable by its striking dorsal markings; a series of large brown saddles (edged in darker brown) on a light brown background that run from head to tail. The saddles are usually separated by rows of dark brown dots. Occasionally, other patterns occur, such as irregular dark stripes running horizontally along the body (see leopard houndshark image #281) or irregular spots and blotches over the entire dorsum. Ventral surface pale.
Maximum length approximated 180cm. One individual reportedly 213cm. Size at birth 17-20cm.
A temperate water species inhabiting shallow muddy or sandy bays, estuaries, sloughs, rocky reefs, and kelp forests. Intertidal to 91m but usually 1-20m.
Pacific coast of North America. Found from Washington State to Mazatlan, Mexico, including the Gulf of California.
The leopard shark is one of the most common nearshore sharks in the temperate eastern Pacific. They appear to exhibit limited long distance movement, and as a result it is thought that the population consists of three regional population clusters in northern California, southern California and Mexico with limited genetic exchange.
In California, where nearly all of the U.S. harvest occurs, the Leopard Shark is taken primarily by recreational anglers, although it is also caught incidentally in commercial fisheries. The species has also been harvested for the cold-water aquarium trade and has been highly prized for its distinctive markings and hardiness. Due to its rather limited geographical range and limited exchange among regional stocks, resident stocks near large population centres may be particularly vulnerable to heavy localized fishing pressure. However, this species does not appear to be at risk judging by the combined landings in relation to previously calculated estimates of fishing mortality and exploitation rates. Additionally, current conservation and regulatory actions enacted by the California Department of Fish and Wildlife appear to have reduced these rates and have contributed significantly toward protecting this species from excessive harvesting in recent years and there is evidence that the leopard shark population has been increasing as a result of these management actions.
Little is known of the biology, historical population abundance and full extent of harvest of this species in Mexican waters, but it is estimated to be less than one percent of the Pacific Ocean catch off Baja California and rarely caught in the Gulf of California. As a result of the success of the conservation measures taken in the U.S. and the lack of a significant fishery in Mexican waters, this species is assessed as Least Concern. However, due to the fact that this species is endemic to this region, is subjected to recreational fishing and bycatch pressures (albeit regulated in the U.S.), is susceptible to overfishing due to its life history characteristics (slow growing, long lived, late maturing, low productivity), and is impacted by habitat loss and degradation, it is important to continue managing and monitoring the species to ensure the health of the species.
Citations and References
Carlisle, A.B., Smith, S.E., Launer, A.L. & White, C.F. 2015. Triakis semifasciata. The IUCN Red List of Threatened Species 2015: e.T39363A80672743. https://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T39363A80672743.en. Downloaded on 25 October 2020.
An aplacental viviparous species (without a yolk-sac placenta). Up to 36 pups per litter. Gestation is approximately 10-11 months. The reproductive cycle is annual.
An opportunistic benthic predator that feeds heavily on a wide variety of invertebrates and small fishes. Leopard sharks are known to gorge themselves on fish eggs when available.
Leopard houndsharks form large nomadic schools, generally segregated by size and sex. They are known to mix with other elasmobranch species such as gray and brown smoothhounds, bat rays, and shovelnose guitarfish. The schools move inshore with the rising tide to feed on intertidal invertebrates. Their migratory patterns (if any) are still unclear.
Reaction to divers
Fairly easy to approach to within 2-3m by snorkelers but difficult to approach on scuba. During baited snorkeling encounters, leopard sharks will make close passes but they are still wary of divers. From personal experience, even while using a rebreather they remained extremely skittish.
By far the most convenient and reliable place to encounter leopard houndsharks is at La Jolla Shores, north of San Diego, CA. During mid to late summer, scores of leopard sharks migrate into the shallows to feed. The best spot to see them is in front of The Marine Room; a restaurant at the south end of the main surfing beach.
The sharks hunt in the shallows between the shore and the surf line, so it is possible to see them simply by snorkeling right off the beach.