Tawny Nurse Shark, Nurse Shark.
Head broad. Snout short and bluntly rounded; pointed when viewed laterally. Mouth small. Nasal flaps form long, thin barbells. First dorsal fin positioned far back on body; origin over pelvic fin origin. Second dorsal large but smaller than first. Second dorsal origin over anal fin origin. Lower caudal lobe indistinct. Caudal fin very long with a small terminal notch close to the tip.
Dorsal coloration tan to dark brown. Ventral surface pale.
Maximum recorded length 320cm. Size at birth 40-60cm.
A tropical species preferring shallow sandy bays, coral reefs, and sea grass beds. estuaries, eelgrass beds, and rocky reefs. Usually found on or near the bottom from close inshore to at least 70m.
The tawny nurse shark is found throughout the tropical Indo-Pacific as far east as the Society Islands in French Polynesia. It is absent from the eastern Pacific. In the Indian Ocean it is found from South Africa to the Red Sea, around Madagascar, India, Southeast Asia, and northern Australia.
The tawny nurse shark is restricted to a narrow band of shallow water habitat (5 to 30 m, occasionally to 70 m) that is heavily fished throughout all its range except Australia. Taken in inshore fisheries (demersal trawls, floating and fixed bottom gill nets and baited hooks) in Indonesia, Thailand, Philippines, Pakistan and India. Although there are limited data on population declines in these areas, reports of local extinctions in India and Thailand, combined with its narrow habitat range, apparently limited dispersion and low fecundity, indicate that the species is highly susceptible to local inshore fisheries and has declined in a large proportion of its range. Within Australia it is assessed as Least Concern because it is widely distributed and abundant, captured only in very small numbers in gillnets and beach meshing.
Citations and References
Pillans, R. (SSG Australia & Oceania Regional Workshop, March 2003). 2003. Nebrius ferrugineus. The IUCN Red List of Threatened Species 2003: e.T41835A10576661. https://dx.doi.org/10.2305/IUCN.UK.2003.RLTS.T41835A10576661.en. Downloaded on 27 December 2020.
An aplacental viviparous species (without a yolk-sac placenta). 4-8 pups per litter. Fetuses are oophagous; consuming unfertilized eggs once their yolk sac has been depleted.
The Pacific nurse shark preys on a wide variety of invertebrates (corals, crustaceans, cephalopods, etc) small fishes, and occasionally sea snakes.
Pacific nurse sharks are often found resting in small groups. They are nocturnal hunters that use their powerful pharynx muscles to suck prey out of holes in the reef.
Reaction to divers
Very easy to approach when resting under reef ledges.
Pacific nurse sharks are quite common throughout their range and are easily encountered in numerous countries.
In Australia, one of the best places to look for them is Lady Elliott Island off the coast of Queensland. They are also common off of Exmouth and on Ningaloo Reef.
Arabian Carpetshark Distinguished by smaller size, more slender appearance and much greater relative distance between the pectoral fins and caudal fin.
Brownbanded Bamboo Shark Distinguished by smaller size, more slender appearance, greater relative distance between the pectoral fins and anal fin. A rounded anal fin, and rounded caudal fin tips.