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The lemon shark, Negaprion brevirostris, is a shark in the family Carcharhinidae, can grow to 10 feet (3.0 m) long. It is known as the lemon shark because light interacting at certain depths with the local seawater can give this shark a tanned and yellow, pitted appearance, much like the surface of a lemon.
The Lemon Shark commonly attains a length of 2.4 to 3.1 m (7.9 to 10 ft) and a weight of up to 90 kg (200 lb) at adulthood, although sexual maturity is attained at 2.24 m (7.3 ft) in males and 2.4 m (7.9 ft) in females. The maximum recorded length and weight is 3.43 m (11.3 ft) and 183.7 kg (405 lb). This stocky, powerful shark is named for its pale yellow-brown to grey skin, which lacks any distinctive markings. This provides perfect camouflage when swimming over the sandy seafloor in its coastal habitat. It is also named for the distinct scent of citrus that emanates from the Lemon Shark. It has a flattened head with a short, broad snout, and the second dorsal fin is almost as large as the first.
Distribution and habitat
The lemon shark is found mainly along the subtropical and tropical parts of the Atlantic and Pacific coasts of North and South America, and around Pacific islands. The longest lemon shark recorded was 13 ft (4.0 m) long, but they are usually 8–10 ft (2.4–3.0 m). They inhabit mostly tropical waters, stay at moderate depths, and are often accompanied by remoras.
Lemon sharks are viviparous, females giving birth to between four and 17 young every other year in warm and shallow lagoons. The young have to fend for themselves from birth, and remain in shallow water near mangroves until they grow larger. With increasing size, they venture further away from their birthplaces. At maturity, at a size of 1.5–2 m and an age of 12–15 years, they leave shallow water and move into deeper waters offshore. However, little is known of this life stage.
Recent work in genetics by Kevin Feldheim and Samuel Gruber may suggest adult sharks travel hundreds of kilometers to mate. Another possibility is that populations far apart may have been separated in recent times. Further research is needed for an understanding of the lemon shark's breeding behavior and ecology.
Importance to humans
Lemon sharks are a popular choice for study by scientists, as they survive well in captivity, unlike many other species, such as the great white, which die in captivity because of food refusal. The species is the best known of all sharks in terms of behavior and ecology, mainly because of the work of Samuel Gruber at the University of Miami, who has been studying the lemon shark both in the field and in the laboratory since 1967. The population around the Bimini Islands in the western Bahamas, where Gruber's Bimini Biological Field Station is situated, is probably the best known of all shark populations. As of 2007, this population is experiencing a severe decline and may disappear altogether as a result of destruction of the mangroves for construction of a golf resort. Of the 22 known lemon shark attacks since 1580, none has resulted in death.
All sharks have electroreceptors concentrated in their heads, called the ampullae of Lorenzini. These receptors detect electrical pulses emitted by potential prey. Lemon sharks are bottom dwellers. They have very poor eyesight and cannot see well to find their food, but are equipped with extremely sensitive and accurate electroreceptors in the nose.
This article incorporates text from the ARKive fact-file "Lemon shark" under the Creative Commons Attribution-ShareAlike 3.0 Unported License and the GFDL.
- Sundström, L.F. (2005). "Negaprion brevirostris". IUCN Red List of Threatened Species. Version 2011.1. International Union for Conservation of Nature. http://www.iucnredlist.org/apps/redlist/details/39380. Retrieved 20 August 2011.
- Lemon Shark - SharkSurvivor.com
- Negaprion brevirostris, Lemon shark - FishBase
- 3.Carwardine, M. and Watterson, K. (2002) The Shark Watcher’s Handbook. BBC Worldwide Ltd, London.
- 2.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 Agricultural Organization of the United Nations, Rome. It can vary in color from a sandy yellow to a brownish yellow, depending on location. It also has poor eyesight but amazing senses to help in hunting.
- "Negaprion brevirostris". Integrated Taxonomic Information System. http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=160433. Retrieved 23 January 2006.
- Froese, Rainer, and Daniel Pauly, eds. (2005). "Negaprion brevirostris" in FishBase. March 2005 version.
- Washington Post, 2005, Aug. 22nd: "Scientists Fear Oceans on the Cusp Of a Wave of Marine Extinctions"