• Shark Guardian

Zebra Sharks

Updated: Oct 16, 2020

Zebra sharks (Stegostoma fasciatum) are known in Thailand and around the Andaman Sea as Leopard sharks. This is confusing as there is another species of shark called the Leopard shark (Triakis semifasciata) found along the Pacific North American coast (See image below). It is an amazing experience as a diver to get close to these sharks whilst they move slowly across the sea bed. Unfortunately sightings of them are becoming more and more rare. Hopefully with your help through citizen science and investigation into why their population is decreasing, we can play a part in their spectacular come back.

Photo Credit: Zebra Shark by Ivan Hiver

Anatomy and Appearance

There is no size difference between males and females and they can grow to a length of 3.5 meters, with its tail, or lower caudal fin to give it its proper name, making up nearly half of that length! It has small barbels (slender, whisker-like sensory organs) on its snout, a small mouth, and small eyes. Their spiracle is located just behind the eye. Its teeth are pointed, with each tooth having two smaller, lateral, flanking points with prominent ridges. The name 'leopard' comes from its' adult appearance. Their juvenile appearance however is completely different with white and black stripe patterns. This is why they are called Zebra Sharks.

Juvenile Zebra Shark

https://creativecommons.org/licenses/by-sa/3.0), via Wikimedia Commons

A female albino zebra shark, measuring 2 meters, was found with no 'spots' at all but divers were able to identify her due to her five dorsal ridges, one along the dorsal midline and two either side which are quite prominent. The two pectoral fins are broad and they have been known to prop themselves up using these when resting on the sea floor. The dorsal fins are smaller and pelvic and anal fins are even smaller again.

Zebra sharks (Stegostoma fasciatum) - also known as Leopard Sharks in Asia

Photo Credit: Ivan Hiver

The "REAL" Leopard shark (Triakis semifasciata)

By Mfield, Matthew Field, www.photography.mattfield.com

Habitat and Migration

They are found throughout the tropical indo-pacific region on sandy flats and in and around coral reefs at depths of up to 62 meters. In Australia's summer and autumn period, Zebra sharks have been known to migrate to shallow coastal coral areas from deeper waters. Channels between the coral reefs are ideal for them to rest in the day, as it a provides faster, more oxygenated flow of water. In these channels they use their pectoral fins to prop themselves up whilst opening their mouths so that water can enter and respiration is possible with very little effort. In stronger currents they have also been observed 'surfing', using their pectoral fins, not to lean on, but to undulate, keeping themselves steady in the current.