Species Fact Profile: Zebra Shark (Stegostoma fasciatum)

Zebra Shark

Stegostoma fasciatum (Hermann, 1783)

Range: Tropical Indo-Pacific Ocean (South Africa to Australia)

Habitat: Coral Reefs and Sandy-Bottom Ocean (down to 60 meters)

Diet: Mollusks (Gastropods and Bivalves), Crustaceans, Small Fish, Marin Worms

Social Grouping: Usually solitary, but sometimes in groups as large as 50, in rare cases congregations of several hundred, usually strong female bias

Reproduction:  Breed year-round.  Courtship consists of male following female, biting at her fins.  Copulations lasts 2-5 minutes.  Female releases eggs over several months, may be able to store sperm.  Incubation period about 6.5 months.  No parental care.  Juveniles are rarely seen, spend most time in deeper water.  Mature at 1.5-1.8 meters.  Parthenogensis has been documented

Lifespan: 25-30 Years

      Conservation Status: IUCN Endangered

• Adult body length 2.5-3.o meters, with maximum reported (but unconfirmed) size of 3.5 meters.  Males tend to be larger than females.  Body is cylindrical with later ridges.  Large, broad tail is about as long as the body.  Head is broad with large eyes, nostrils close to the front of the snout, small barbels
• Yellow/brown/gray background coloration is covered with dark stripes in juveniles, which turn into spots in adults.  The common name comes from the juvenile pattern, which has led to confusion by some parties, including the early belief that the juveniles and adults were separate species (juveniles also lack the body ridges seen in adults).
• Nocturnal, spending most of the day lying motionless on the seafloor (can pump water across the gills through the mouth, so can breathe while it is stationary).  At night, they actively feed by swimming in and out of crevices in the coral reef
• Predators include larger bony fish and sharks, as well as marine mammals
• Largely sedentary, genetic data shows little exchange of genes between neighboring populations
• Not of commercial importance to most fishermen, though sometimes fished for recreationally.  Most often taken incidentally as bycatch in nets, in which case the meat and fins are dried, sold.  Regularly seen in fish markets in South and Southeast Asia.  Strong site fidelity to particular reefs could make them vulnerable to future targeted fishing
• Considered relatively gentle and inoffensive, but have bitten divers who have harassed them, with a single reported case of a zebra shark attacking a human unprovoked (no injuries resulted)