Caribbean reef shark

3/6/2017

Although it’s summer in the Southern Hemisphere, TFUI Founder Melissa has been freezing her butt off and wishing more than anything to return to her birthplace in the Caribbean. She wouldn’t mind going diving with this week’s critter, the Caribbean reef shark (Carcharhinus perezi), either.

Despite it being one of the most common requiem shark to encounter in the Caribbean, it is also one of the least-studied. It is viviparous, and females give birth to 4-6 pups biannually. A member of the Carcharhinidae family (the requiem sharks), like most in this family they are robust and streamlined gray in colour. It's hard to tell this species apart from other members in this family, such as the dusky shark (C. obscurus) and silky shark (C. falciformis). However, Caribbean reef sharks have darker tipped fins and a free rear second dorsal fin. They are probably one of the largest sharks you would encounter on a reef, measuring up to 3 m (10 ft), but usually are around 2 - 2.5 m (6.5 - 8 ft) long. They scour the reef at night for their prey (e.g. teleost fish and cephalopods). Juvenile Caribbean reef sharks are known to even feast on shrimp!

They have been observed resting on the bottom of the sea or inside caves, if only for a minute or two. Odd, as many sharks do no exhibit this resting behaviour. In the 1970's, Eugenie Clark researched the "sleeping sharks" inside the caves at Isla Mujeres off the Yucatan Peninsula. These Caribbean reef sharks were not sleeping at all, as their eyes would follow divers! It was found that this area had low salinity and high oxygen. Dr. Clark hypothesized that the freshwater inside the caves might be loosening parasites on the sharks and produce a sort of "narcotic" effect. When threatened, these animals will perform a threat display of hunching their backs and lowering their pectoral fins. They are also known to have nictitating membranes (a protective "eyelid").

These sharks are caught for their meat (for consumption and for leather), fins, liver oil, and to use as fishmeal. They’re quite popular for ecotourism in this area, too! The IUCN has assessed the Caribbean reef shark as Near Threatened (NT) due to populations off of Belize and Cuba declining from overfishing, exploitation, and threatened by the habitat degradation and destruction to their coral reefs.

ever gone diving with these sharks?

glossary

Cephalopods: The most intelligent, mobile, and largest of all molluscs. These include: squid, octopuses, cuttlefish, the chambered nautilus, and their relatives.
Dorsal fin: Fin located on the back.
Dorsal side: The top of an animal.
Gestation: The period in which a fetus develops, beginning with fertilization and ends at birth.
IUCN: International Union for Conservation of Nature.
Pup: Give birth to baby sharks (pups).
Pups: Baby sharks.
Teleost fish: Bony fish.
Viviparous: Eggs hatch inside the female's body and the babies are fed by a placenta which transfers nourishment from the mother to the babies (via an umbilical cord which is connected to the baby shark behind the between the pectoral fins).