|Scientific Name:||Negaprion brevirostris|
|Species Authority:||(Poey, 1868)|
Hypoprion brevirostris Poey, 1868
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Reviewer/s:||Musick, J.A. & Fowler, S.L. (Shark Red List Authority)|
This assessment is based on the information published in the 2005 shark status survey (Fowler et al. 2005).
The Lemon Shark (Negaprion brevirostris) is a large coastal shark that is common in the Atlantic Ocean along the coasts of the United States to Brazil and possibly in some areas on the West African coast, as well as in the Pacific from Baja California to Ecuador. Young sharks are highly site attached but adults may undertake long migrations, possibly to deeper waters at the onset of winter. The species is caught both in commercial and recreational fisheries, but no management plans are implemented.
|Range Description:||This inshore species is common along the coasts in the Atlantic Ocean ranging from the US in the north down to southern Brazil and possibly in some areas on the West African Coast. It is not known whether these populations are the same species (Compagno 1984). Lemon Sharks also occur in the Pacific Ocean from Baja California in the north to Ecuador in the south.|
Native:Belize; Brazil; Costa Rica; Ecuador; El Salvador; French Guiana; Guatemala; Guyana; Honduras; Mexico; Nicaragua; Panama; Saint Lucia; Suriname; United States (California); Venezuela
|FAO Marine Fishing Areas:||
Atlantic – eastern central; Atlantic – northwest; Atlantic – southeast; Atlantic – southwest; Atlantic – western central; Pacific – eastern central; Pacific – southeast
|Range Map:||Click here to open the map viewer and explore range.|
|Habitat and Ecology:||
The Lemon Shark inhabits shallow waters around coral keys, mangrove fringes, around docks, on sand or coral mud bottoms, in saline creeks, in enclosed sounds or bays and in river mouths. It may enter fresh water but has not been found far up in rivers (Compagno 1984b). Occasionally it ventures into the open ocean and has been found down at depths of at least 90 m (Springer 1950).
Mating occurs during spring and summer with parturition in shallow nursery grounds the following year after a 10?12 month gestation period (Bigelow and Schroeder 1948, Springer 1950, Clark and von Schmidt 1965). The female Lemon Shark gives birth to 4?17 young (Clark and von Schmidt 1965, Compagno 1984b) of 50?60 cm TL (Gruber and Stout 1983, Brown and Gruber 1988). Maturity is reached at 225 cm (males) and 235 cm (females) or at an age of 12 and 13 years, respectively (Compagno 1984b, Brown and Gruber 1988). Growth follows the von Bertalanffy equation (Brown and Gruber 1988):
PCL = 317.65 × (1-e -0.057 (t + 2.302)), n = 110, r2 = 0.99 , where PCL is precaudal length (m) at time t (yrs).
This equation assumes the maximum length to be 317 cm, but the lemon shark can become bigger. Hueter and Gruber (1982) examined a 368 cm large male. The normal size range of the adult is 250?290 cm with females being slightly bigger than males (Brown and Gruber 1988) but sizes of up to 3 m or more are not unusual (Clark and von Schmidt 1965). At this size the shark would have a weight of approximately 250 kg (Gruber 1984) and is probably more than 30 years old.
Activity space ranges from a few km² in the highly site-attached juveniles (Morrissey and Gruber 1993a) up to several hundred km² in the more active adults (Compagno 1984b). Juvenile Lemon Sharks appear to select shallow (0?50 cm) and warmer water (30°C or more). They also prefer rocky or sandy substrate (Morrissey and Gruber 1993b). Almost all field research on the Lemon Shark originates from the waters in and around the Bimini Lagoon, Bahamas where a high annual, density-dependent mortality rate (35?62%) for young-of-the-year Lemon Sharks was found (Gruber et al. 2001). This is probably due to predation by larger sharks (Manire and Gruber 1993). Jacobsen (1987) suggested that the same area could support about 250 juveniles while Henningsen and Gruber (1985) estimated the population to be around 500 specimens with a density of five sharks per km². The annual production of these Lemon Sharks was 320 kg corresponding to about 0.3 g of new Lemon Shark tissue for every m² of lagoon (Henningsen 1989). Later, Gruber et al. (2001) estimated that the maximum number of juveniles that could survive each year in the Bimini Lagoon was 30. Young Lemon Sharks feed mainly on teleosts, crustaceans (small portunid crabs and panaeid shrimp) and octopods. As they grow the diet becomes dominated by teleost and cartilaginous fishes and the adults even eat sea birds (Springer 1950, Cortés and Gruber 1990). The energy consumed and later used for growth depends on the daily feeding rate but maximum conversion rate is probably close to 25% (Cortés and Gruber 1994).
|Major Threat(s):||Lemon Sharks are caught commercially on longlines and the meat is dried, salted, or smoked. The fins fetch a very high price. The Lemon Shark is consumed in the United States and in Central and South America (Rose 1996). The rough and heavy skin has made the lemon shark preferable among tanneries for the production of leather. However, it is not included in TRAFFIC Network?s list of species frequently appearing in available information on worldwide shark fisheries (Rose 1996). It is a target species in Belize, Mexico and USA and reported as bycatch in St Lucia (Oliver 1996, Anon. 1997). Lemon Sharks were seen at a fish market in Cameroon in 1991, but not since then (C. Grist pers. comm.). The species is also caught in recreational fishing and was reported as the 13th most common shark species in the US recreational fishery (Casey and Hoey 1985). A decrease in the number of juvenile Lemon Sharks between 1986?1989 in the lower Florida Keys may have been caused by several years of shark fishing tournaments and 20 years of targeting with gillnets affecting the return of females to bear new litters (Manire and Gruber 1990). The Lemon Shark is a popular aquarium species and it is also used extensively for research purposes. Lemon Sharks used to be common in the western Atlantic, from New Jersey, USA to Brazil, but lately their numbers have been depleted, especially around Florida (S.H. Gruber pers. comm.).|
|Conservation Actions:||There are no management plans in place for the Lemon Shark. Some research, however, has dealt with related issues so there is a base of knowledge should a plan ever be implemented.|
|Citation:||Sundström, L.F. 2009. Negaprion brevirostris. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 19 June 2013.|
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