Tawny nurse shark - Nebrius ferrugineus

 

Illustration © Marc Dando

WHAT TO LOOK FOR
This shark has fairly long barbels, a tiny spiracle. Its large first dorsal fin’s base is over its pelvic fin bases. It has angular fins, with its caudal fin fairly long (about 25% of its length).

COLOR
Color may slowly change between shades of brown, depending on its habitat.

SIZE
At birth, the shark is 1.3 to 2 ft [40 to 60 cm] in length. It matures at approximately 8.2 ft [250 cm], and may reach a maximum length of 10.3 to10.5 ft [3.1 to 3.2 m].

HABITAT
These sharks are found on or near the bottom in sheltered areas: lagoons (particularly juveniles), channels, crevices and caves in outer coral and rocky reef edges, seagrass, and sand, on and near reefs and off beaches. They range from intertidal to depths of more than 229.7 ft [70 m], but mostly range from 16.4 to 98.4 ft [5 to 30 m].

DISTRIBUTION
These sharks are wide-ranging in the tropical Indo-Pacific Ocean from South Africa to the Red Sea and Gulf, East Asia north to Japan, Australia to Marshall Islands, and Tahiti.

BIOLOGY

  • Prey – Young feed inside the uterus on large unfertilized eggs (oophagy). After birth, sharks feed on corals, crustaceans, cephalopods, sea urchins, and reef fish. They occasionally eat sea snakes.

  • Reproduction – Ovoviviparous (aplacental viviparous). Litter size is uncertain (1-4, depending upon competition in the uterus).

BEHAVIOR
These sharks are mostly nocturnal, and prowl reeds at night in search of prey to suck out of crevices. The sharks aggregate in shelter by the day. They have a limited home range, and often return to the same resting place. They may ‘spit’ water when caught and spin on the line when hooked. They are docile and popular with divers, but may bite if they are harassed. They are hardy in aquaria.

STATUS
These sharks are vulnerable, and are fished through much of their range.