Whitetip Reef Shark - Oceana

Sharks & Rays

Whitetip Reef Shark

Triaenodon obesus

Distribution

Indian and Pacific Oceans in tropical and subtropical waters

ecosystem/habitat

Coastal waters and coral reefs

Feeding Habits

Aggressive predator

Taxonomy

Class Chondrichthyes, Order Carcharhiniforms (ground sharks), Family Carcharhinidae (requiem sharks)

 

The whitetip reef shark is a slim, medium-sized shark characterized by its white-tipped dorsal and tail fins that give this species its name. Whitetip reef sharks are known for using their slender bodies to maneuver through caves and crevices throughout their coral reef habitats in the Indian and Pacific Oceans.1

The whitetip reef shark is a common and broadly distributed species. They are nocturnal, spending their nights hunting and their days resting in reef caves or sandy bottoms with large groups of fellow whitetips. In caves, whitetip reef sharks pile on top of each other like logs, lying motionless for hours because this species does not need to move to breathe. They often return to the same home cave for days or weeks at a time, sometimes longer.2

Whitetip reef sharks grow to an average length of 5.3 feet (1.6 m). The maximum weight ever recorded was 40.3 pounds (18.3 kg) and the maximum length ever recorded was 7 feet (2.1 m), but a length over 5.3 feet (1.6 m) is extremely rare. Whitetip reef sharks mate via internal fertilization and give birth to one to five pups per litter.3 They reach sexual maturity at the relatively late age2 of 8 years and live until the maximum age of at least 25 years.3

At night, whitetip reef sharks become active and hunt for bottom-dwelling prey hiding in coral reef holes and crevices. Whitetip reef sharks feed primarily on octopuses, crustaceans and reef fish, including eels, snappers, parrotfish and triggerfish. As a hunting method, whitetip reef sharks sometimes chase and trap their prey in crevices where they can easily jam their slim bodies and snouts to catch it.1 Like all sharks, whitetip reef sharks rely on electroreceptors in their snouts to detect the electrical charges of nearby prey.3 Although they are formidable predators, whitetip reef sharks are preyed upon by larger fish, such as tiger sharks and giant grouper.

Whitetip reef sharks are also vulnerable to predation from humans. They are fished commercially using line and trawl nets for tropical markets. Once abundant, whitetip reef shark numbers depleted noticeably from 1985 to 2005 due to overfishing in certain areas.2 Their shallow water habitats (33 to 131 feet/10 to 40 m) have made them susceptible to becoming bycatch in gillnet and longline fisheries, as well.3 Whitetip reef sharks are considered near threatened with extinction due to their small litter size, late age of maturity and coral reef habitat loss. Without proper, enforced fisheries management, this species may become threatened with extinction.2

Fun Facts About Whitetip Reef Sharks

1. Whitetip reef sharks grow to a maximum length of 7 feet (2.1 m) and weight of 40.3 pounds (18.3 kg).

2. Whitetip reef sharks can be found as deep as 1,083 feet (330 m).

3. Whitetip reef sharks live communally in small home ranges anywhere from 0.2 to 1.8 miles (0.3 to 3 km).

4. Whitetip reef sharks have been around for at least 42 million years.3

5. Whitetip reef sharks do not have to move to breathe and can be found lying motionless on the seafloor.

6. Whitetip reef sharks appear grumpy because of their down-turned mouth and protruding brow ridges.

7. Whitetip reef sharks are regarded as guardian spirits, or “aumakua,” in some Hawaiian traditions.1

Engage Youth with Sailors for the Sea

Oceana joined forces with Sailors for the Sea, an ocean conservation organization dedicated to educating and engaging the world’s boating community. Sailors for the Sea developed the KELP (Kids Environmental Lesson Plans) program to create the next generation of ocean stewards. Click here or below to download hands-on marine science activities for kids.

Kids Environmental Lesson Plans

References:

1 Florida Museum

2 IUCN Red List

3 Aquarium of the Pacific