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Leopard shark (Triakis semifasciata) – Video

This video was filmed during my visit to the Sea World, California, USA.

Introduction: The leopard shark, Triakis semifasciata belongs to the hound shark, in the family Triakidae. The species is small and pretty animals. The species is harmless to humans if they are not disturbed and hence divers can safely come close enough to the leopard shark and photograph them especially when not agitated or frightened. In fact, only a single mild injury for a diver was reported in 1955.

The species have lived in aquariums for up to 20 years while their lifespan in the wild is up to 30 years.

Range and habitats: Leopard sharks are found in the Eastern North Pacific Ocean: from the coast of Oregon to the Gulf of California, Mexico. They occur in abundance in San Francisco Bay and other large estuaries. The leopard shark inhabits inshore and offshore cool and temperate waters.

In shallow waters, the species is most common on or near the bottom between zero to 4 meters. Inhabiting a depth of up to 90 meters has been reported. Leopard sharks prefer sand flats, muddy bays and rocky bottoms near reef sites and kelp beds.

Description: The leopard shark has been named for its for its distinctive bold dark saddles and spots on the fins and upper body. The species is characterized by their gray to bronze-gray upper bodies with light ventral side.

The species have relatively broadly-rounded and short snouts. Leopard shark teeth are arranged in overlapping rows.

The average size of adult leopard shark ranges between 1.2-1.5 m with a maximum reported total length of about 1.8 m with a maximum weight of about 19 kg.

Feeding habits: Leopard sharks are opportunistic feeder preying primarily on bottom-living invertebrates. While invertebrates dominate their diet, other preys have been found in their stomachs including worms, crabs, shrimp, clams, octopus, and other small sharks. Their feeding habits may change according their size as well as the seasons.

On the other hand, the small leopard sharks are preyed upon by large sharks such as the great white shark and the broadnose sevengill shark.

Reproduction: Leopard sharks are Ovoviviparous animal producing between about 4 to 30 pops per litter after a gestation period of about 10-12 months. Being an Ovoviviparous, the eggs produced by the female are maintained in a brood chamber until the embryos develop relying on nourishment from a yolk sac and hatch internally within the mother’s uterus. Upon birth, the pop size is about 20 cm.

Leopard sharks reach their sexual maturity at about 10 years whereas the size of mature female ranges from 1.1 to 1.3 m compared to 0.7 to 1.2 m for mature male.

Habits: The leopard sharks are nocturnal animals and normally sleep during the day. They can be found resting still on sandy bottoms.

With the exception of few specimens of leopard sharks found hundreds of miles away from their home, the species are known to remain in the same area for much of their lives (homebodies). Leopard sharks are strong swimmers and they are known to swim a strong undulating motion in large groups.

Adaptation to environmental conditions: Leopard shark was found to have numerous small red blood cells compared to related shark species. This adaptation enables the species to absorb oxygen more easily in low oxygen environments such as estuaries which is considered a competitive advantage over some of its close relatives of sharks.

Utilization: The leopard shark’s meat is used for human consumption, and it is usually commercially fished and by recreational anglers.

Threats and conservation

Threats: Because of their slow growth rate and their late maturity (about 10 years) as well as their few progeny,this species has been believed to be vulnerable to overfishing. However, according to the International Union for Conservation of Nature (IUCN) Red List of Threatened Species criteria, the species have been listed as Least Concern.Conservation initiatives: In order to protect the core population of leopard shark in the light of the increase of spearfishing, the state of California (USA) implemented fishery management regulations in 1992 to protect the core population of the species in California and Oregon waters from overfishing and reduce its harvesting to sustainable levels.

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