Grey Reef Shark
The Grey Reef shark (Carcharhinus amblyrhynchos) is part of the family of requiem sharks, along with the Blacktip Reef shark and the Whitetip reef shark. It has a classic shark-like body – with a streamlined shape and a grey-brown coloration and is commonly found in tropical waters around coral reefs.
Grey Reef shark anatomy and appearance
The Grey Reef shark grows to an average of 1.8 to 1.9 meters in length, with the largest measuring 2.5 meters. Grey Reef sharks have also been recorded to weigh around 33 kilograms. They have fusiform body shapes – typical of most requiem sharks. Grey Reef sharks have long, round snouts and serrated, triangular teeth with cusps, and lack an interdorsal ridge.
Although they may appear solid grey in color from afar, a brownish tint can be seen at a closer distance. This gray-brown coloration appears on the dorsal side, with the color fading to white on the ventral side. Grey Reef sharks have characteristic dark markings. One of the Grey Reef sharks’ most distinguishing features is the dark margin on the caudal fin’s trailing edge. Their pectoral, second dorsal, anal, and pelvic fins also have dark tips. While the first dorsal fins don’t have any dark markings, they are not always completely grey. Some Grey Reef sharks have a white tip on their first dorsal fins, and some scientists suspect it could be related to the shark’s geographic location.
Other species of the Carcharhinus genus are also commonly confused with the Grey Reef shark. Both the Blacktip shark (Carcharhinus limbatus) and the Blacktip Reef shark (Carcharhinus melanopterus) have black tips on their dorsal fins that Grey Reef sharks don’t have. Additionally, the Silvertip shark (Carcharhinus albimarginatus) has a white margin on its caudal fin instead of a black margin on its caudal fin like the Grey Reef shark has.
Grey Reef shark habitat
Grey Reef sharks are found throughout the Pacific and Indian Oceans along with the Red Sea in tropical waters. Although they are able to dive deep into the ocean, they prefer shallow waters up to 50 meters from the surface. As their name suggests, these sharks prefer living around coral reefs, oftentimes near drop-offs deeper into the ocean or in lagoons near strong currents. Even though Grey Reef sharks do spend time traveling, they have been found to display site fidelity and will return to the same areas.
Other sharks also inhabit similar areas as the Grey Reef shark. These sharks include the Blacktip Reef shark and the Whitetip Reef shark (Triaenodon obesus).
Grey Reef shark diet
Grey Reef sharks hunt at night. A wide variety of prey makes up their diet. They will hunt reef fishes that are less than 30 centimeters in length, and will also prey on cephalopods like squid and octopus and crustaceans like shrimp, lobster, and crab. In order to hunt, these sharks rely on their sense of smell along with electric fields created by ampullae of Lorenzi, which are pores around their snouts. While Grey Reef sharks normally swim slowly at around one kilometer per hour, once hunting begins, they speed up, reaching speeds of 48 kilometers per hour. During this time, they also tend to become more aggressive. Larger sharks like Silvertip sharks and Tiger sharks (Galeocerdo cuvier) are considered as a few of the Grey Reef sharks’ predators.
Grey Reef shark population
Grey Reef sharks have an average lifespan of around 25 years. They mature at around 7 years of age, with males measuring 1.3 to 1.45 meters in length and females measuring 1.2 to 1.3 meters in length. Gestation is around 12 months. Grey Reef sharks are ovoviviparous. The embryos don’t receive nourishment through a placenta, but they feed through oophagy – a process in which they eat unfertilized eggs for nourishment. Grey Reef sharks give live birth to litters of 1-6 pups, with each pup measuring 45-60 centimeters long.
Grey Reef sharks are known to be social, and will gather in groups during the day. Since they are nocturnal, they are more active at night. These sharks are thought to be more inquisitive and have been known to approach divers out of curiosity. Although some consider these sharks to be aggressive, they don’t normally attack unless they feel threatened.
Grey Reef shark conservation
The IUCN (International Union for Conservation of Nature) listed the Grey Reef shark as 'Endangered' in 2020. They are fished commercially for their fins in shark fin soup. Since these sharks tend to prefer waters close to the shore and will gather in the same, predictable places, they tend to be vulnerable to overfishing. Coral reef habitat restriction endangers Grey Reef sharks even more.
