[photo credit: Jim Abernethy]
Lemon shark (Negaprion brevirostris)
The Lemon shark is a large-bodied shark that is easily distinguished by its relatively large dorsal fins and yellow-brownish skin. Once one of the most common shark species on both sides of the Atlantic Ocean, Lemon sharks have been reduced to low densities in the waters off West Africa. Luckily, they remains fairly common throughout the Caribbean and are hardly targeted by commercial fisheries, although they are frequently caught by US recreational fishermen. The major threat to Lemon shark populations is probably the degradation of essential habitats such as mangroves and shallow reefs. With the actual status of global populations largely unknown, the Lemon shark is now listed on the IUCN Red List as ‘near threatened’ with extinction.
Throughout its geographical range, from the Eastern coast of the United State down to Brazil, the Lemon shark is mostly found in surface waters to a depth of 92 meters. They prefer the shallow, coastal waters of the tropics, where they can be found close to coral reefs, on sandy bottoms, and between mangroves. Especially the juvenile individuals are often associated with shallow mangrove habitats as they provide ample food and shelter for the growing sharks. They also provide a hiding place away from larger adult Lemon sharks, which are known to be cannibalistic and preying on the young. In general, the Lemon shark’s diet consists mainly of fishes, supplemented with crustaceans and mollusks.
The similar-looking Sharptooth Lemon shark or Sicklefin Lemon shark (Negaprion acutidens) is closely related to the Lemon shark and occupies a similar habitat in the tropical waters of the Indian and Pacific Ocean. The species that we are highlighting here only occurs in the Atlantic Ocean and the Eastern Pacific. Within the Dutch Caribbean, this species has been documented on Aruba, Curacao and St. Maarten, and since two years, juvenile Lemon sharks are observed around St. Eustatius.
At birth, Lemon sharks measure around 60-65 cm and can grow to a maximum reported size of 340 cm. Males mature at a length of approximately 224 cm, whereas females mature at a larger size of approximately 239 cm. The age at which the sharks reach these lengths (and thus reach maturity) has been estimated to be 11,6 years for males and 12,7 for females. The maximum reported age for this species is 27 years, which makes the Lemon shark a slow-growing, long-lived fish species.
Something that is studied extensively about Lemon sharks is the presence of different personalities between individuals and the ability to learn new behaviors. Lemon sharks turn out to be highly social animals and their social behavior is much more complex than previously thought. This knowledge provides a lot of insight into the species, as their social behavior can affect their growth rate, survival and the probability of capture by humans. This is important information to have when trying to improve the population and conservation management programs.Sources: IUCN Red List of Threatened Species Red List status: NEAR THREATENED