Sharptooth lemon shark  (Negaprion acutidens)

This big, stocky shark looks almost identical to the lemon shark (Negaprion brevirostris), but can be distinguished by the rear edge of the pectoral fins, which are slightly more curved, or sickle-shaped. The sharptooth lemon shark has pale yellow-brown skin, a broad, blunt snout, and the second dorsal fin is almost at large as the first (3) (4).

Occurs in the tropical Indian Ocean and the west and central Pacific (4).

The sharptooth lemon shark occurs in tropical waters over continental shelves, down to depths of 30 meters. It seems to prefer bays, estuaries, sandy plateaus, reef shelves and reef lagoons, often in still, turbid water. Young sharks are frequently found on reef flats, where water is shallow enough to expose their dorsal fins (3) (4).

The sharptooth lemon shark is reportedly a sluggish shark that swims slowly near the bottom, frequently resting on the substrate. This shy shark is generally reluctant to approach divers, even when food is used to lure them near. Young sharks are said to be more inquisitive, and a shark of any age is likely to respond to being provoked by humans, or approached by boats, with aggression. The majority of the sharptooth lemon shark's diet consists of bottom-dwelling bony fishes and stingrays (3).

This is a viviparous shark, thus the embryos develop inside, and receive nutrition from, the mother for about ten months. Litters can vary from 1 to 13 young, with each pup measuring about 45 centimetres (3).

The sharptooth lemon shark is known to be caught in several countries, including India and Thailand, for its meat, vitamin rich liver oil, and fins for shark-fin soup (3). It is thought to be vulnerable to over-fishing due to its restricted habitat preferences and small home range. Evidence of local extinctions in India and Thailand confirms this fear. Its preference for inshore habitats also makes this shark susceptible to the threat of habitat degradation; coral reefs are being destroyed by dynamite fishing and pollution, and mangroves are threatened by human development (1).

At present, there are no known conservation measures in place aimed specifically at the sharptooth lemon shark.

For further information see:

• Compagno, L.J.V. (1984) FAO Species Catalogue. Vol 4: Sharks of the World. An annotated and illustrated catalogue of shark species known to date. Part 2: Carcharhiniformes. Food and Agriculture Organization of the United Nations, Rome. Available at:
  www.fao.org/docrep/009/ad123e/ad123e00.htm
• FishBase:
  www.fishbase.org
• Project Aware:
  http://www.projectaware.org/

Authenticated (09/04/08) by Meaghen McCord, South African Shark Conservancy (SASC).
http://www.sharkconservancy.org