The Lemon shark, scientifically known as Negaprion brevirostris, derives its name from its vibrant yellow coloration. Its underside is usually white or a lighter shade of yellow. Apart from yellow, the Lemon shark also exhibits shades of brown and olive grey. This stocky shark species possesses a blunt nose and two dorsal fins of similar size and shape. The first dorsal fin is positioned at the back of the pectoral fins, while the second dorsal fin is located at the front of the anal fin.
The Lemon shark's pelvic fin features weakly concave rear margins, while the pectoral fin's outer margin is slightly convex. Both fins have a weakly falcate shape. The snout of the Lemon shark is round and shorter than the width of its mouth. Unlike some other shark species, the Lemon shark does not have a mid-dorsal ridge. Its teeth are long and sharp, with narrow and broad upper teeth featuring triangular smooth-edged cusps and finely serrated bases. The lower teeth, on the other hand, are narrow and triangular with smooth-edged cusps.
Lemon sharks typically range in length from 2.4 to 3 meters (7.9 to 9.8 feet), with a maximum length of 3.2–3.4 meters (10–11 feet). At birth, Lemon shark pups measure between 24 and 26 inches (60-65 cm) in length. The species has a growth rate of approximately 0.21 inches per year (0.54 cm per year).
As a viviparous species, the Lemon shark gives live birth. After a gestation period of 10 to 12 months, pregnant females migrate to shallow nursery areas during spring and summer to deliver litters of 4 to 17 pups. The young Lemon sharks exhibit a slow growth rate and remain within nursery grounds for an extended period, finding relative safety from predators. These nursery areas, often characterized by mangroves, offer abundant food sources but also possess low oxygen content.
To compensate for the low oxygen levels, Lemon sharks have developed several adaptations, including blood with an unusually high affinity for oxygen. As the sharks mature, their range expands significantly, with distances ranging from 6 to 8 kilometers (3.7 to 5.0 miles) up to approximately 300 kilometers (190 miles). Maturity is generally reached at around 6 and a half years of age, and Lemon sharks are believed to have a lifespan of up to 27 years.
The Lemon shark is a patient hunter, known for its exceptional ability to camouflage within its natural habitat. Its yellow coloring allows it to blend seamlessly with the sandy bottoms of coastal waters. This effective camouflage provides the shark with an advantage when hunting prey and avoiding potential predators. Furthermore, the Lemon shark possesses a unique retinal setup that enables it to see clearly even in the murky depths of the water.
While the Lemon shark has the potential to be aggressive toward humans, most recorded attacks have been provoked. Due to their excellent camouflage abilities, it is easy for individuals to unintentionally disturb the shark, leading to defensive reactions. However, Lemon sharks are generally considered gentle in nature and do not pose a significant threat to humans. Divers and other water enthusiasts often encounter Lemon sharks without any issues. It's important to remember that responsible behavior and respect for their environment are crucial to maintaining a harmonious coexistence.
The Lemon shark's diet primarily consists of bony fish and crustaceans. Its menu includes various species such as catfish, mullet, jacks, croakers, porcupine fish, cowfish, guitarfish, stingrays, eagle rays, crabs, and crayfish. Additionally, the Lemon shark occasionally preys on sea birds and smaller sharks. These sharks consume food until they are full, and the digestion rate depends on the quantity consumed at a given time.
Lemon sharks inhabit the tropical and subtropical waters of the Atlantic and Pacific Oceans, particularly along the coastal areas. They prefer moderately shallow waters, rarely venturing beyond depths of 80 meters (approximately 260 feet). Common habitats include shallow waters near coasts, islands, coral reefs, mangroves, bays, and even river mouths. The Lemon shark's distribution spans from the southeast coast of the United States of America to various regions across the Atlantic and Pacific Oceans.
In terms of threats to humans, Lemon sharks pose a minimal risk. According to the International Shark Attack File, there have been only 10 unprovoked attacks by Lemon sharks, all occurring in Florida and the Caribbean. Notably, there have been no recorded fatal attacks from this species. Lemon sharks often inhabit coastal waters commonly frequented by swimmers, surfers, and divers, indicating their relatively low threat level.
However, Lemon sharks face challenges from human activities such as commercial and recreational fishing. They are frequently targeted by fishermen along the U.S. Atlantic Ocean, Caribbean, and eastern Pacific Ocean. Additionally, Lemon sharks are often caught as by-catch in pelagic and gillnet fisheries. The demand for their fins, which are highly prized for shark fin soup, poses a particular threat. Overfishing has raised concerns about the populations in the western north Atlantic and eastern Pacific Ocean.
To ensure the conservation and protection of the Lemon shark, it is essential to raise awareness about its ecological significance and advocate for sustainable fishing practices. The Lemon shark's contribution to marine ecosystems and its inherent value as a species must be acknowledged and respected.