Gray Reef Shark

Threat Level: low

The Grey Reef Shark is also known as black-vee whaler, gray shark, gray whaler shark, longnose blacktail shark.

GRAY REEF SHARK

Scientific Name.... Carcharhinus Amblyrhynchos
Family Name...... Scyliorhinidae

GENERAL DESCRIPTION

The gray reef shark is gray in color and has a moderately long, broadly rounded snout, eyes usually rounded, they have no interdorsal ridge, large second dorsal fin with short rear tip. Pectoral fins are narrow and falcate.

SIZE

The maximum size of the gray reef shark is approximately 8.3 feet long, but the average size is 5.8 feet. Females mature at 49-55 inches, while males mature at 48 to 57 inches.

TEETH

They have narrow triangular, serrated upper teeth.

COLOR

The gray reef sharks are gray above , and white below. First dorsal is plain or irregularly to prominently white-edged, obvious broad black posterior margin to entire caudal fin, blackish tips to other fins.

FEEDING HABITS

These sharks feed on small bony fishes such as needlefishes, butterflyfishes, morays, squirrelfishes, scorpionfishes, surgeonfishes, parrotfishes. There diet also includes squids, octopuses, and crustaceans, lobster and shrimps. Studies suggest that the gray reef shark feeds more on bottom-dwelling marine life, than mid-water species. Groups of these sharks have been observed herding schooling fish up against the reef before attacking them. They will also follow jacks and will scavenge on the leftovers resulting from the jack feeding events.

SOCIAL BEHAVIOUR

Gray reef sharks are a social species, aggregating by day in or near reef passes or lagoons. Often cruises near bottom but will visit surface to investigate food sources and venture several km offshore before returning to home site. Even more active at night, when groups disperse. Inquisitive, several sharks may approach divers closely in seldom-dived areas, but soon disperse and seldom reappear except at a distance during repeated dives. They display an intimidating threat by by their exaggerating swimming pattern with head and tail wagging in broad sweeps, back arching, head lifting, pectoral fin lowerig and sometimes horizontal spiral swimming is performed if approached too closely or startled, unless food is present. Display varies from almost immediate flight, to a series of figure-eight loops to biting then fleeing. Gray reef sharks are inquisitive and is attracted to the low-frequency underwater sounds and commotion caused by a speared fish, with many stories of a gray reef shark taking a fish off the end of an unsuspecting spearfisher's spear.

HABITAT

They are found in Central Pacific to Madagascar and occurs at depths of 3.4 to 905 feet. They inhabit near coral reefs, where it occurs in lagoons, on the reef face and fore reef slope. It is most abundant on outer reef slopes, and at the entrances of reef passes. In some regions this species is more common around low, coral islands and atolls, rather than around high islands, and is reported to be more common on the leeward side of these islands. It is less likely to be present in shallow, intertidal habitats in regions where it co-occurs with the blacktop reef shark an apparent competitor. The young favor shallower water than adults.

LIFE SPAN

There longevity is believed to be around 25 years.

REPRODUCTION

These sharks are viviparous, yolk-sac placenta, and give birth to 1 to 6 pups. The gestation period is 10-12 months, and females breed biannually. Pups measure about 20 to 24 inches at birth and reach maturity after about 7 years.

SWIMMING

They are very active strong swimmers.

SHARK ATTACKS

Has attacked if threatened. These sharks have severely bitten and injured divers, to threaten them, not to eat them. They should be treated with respect, although most dive encounters with it are without incident.

POPULATION

According to IUCN List ( International Union for Conservation of Nature and Natural Resouces ) they are near threatened. Formerly common in clear tropical coastal waters and oceanic atolls, now under threat because of restricted inshore habitat, site fidelity, small litter size, relatively late age of maturity and increasing unmanaged fishing pressure. More valuable protected for dive tourism than for fisheries.