Lemon sharks use a number of sensory channels. Their retinas have specialized horizontal bands known as "visual streaks" that are extremely rich in cones, which discern color and visual detail. Their vision is very important in prey capture, as evidenced by an experiment conducted at the Lerner Marine Laboratory, which found that temporarily blinded lemon sharks were not able to detect a 113 kg chunk of blue marlin (Makaira mazara), while unimpaired lemons sharks found the blue marlin with ease. Lemon sharks do, however, have an acute sense of smell; another experiment at the same laboratory found that individuals of this species were able to detect one part of tuna juice in 25 million parts of sea water. As with all sharks, lemon sharks have ampullary receptors (Ampullae of Lorenzini) concentrated on their heads, which sense electric charges and serve to help them hone in on prey items. These sharks also have a homing sense, enabling females to return to the same areas each time they give birth and juveniles to return to safe nursery waters.
Communication Channels: visual ; tactile
Perception Channels: visual ; acoustic ; chemical ; electric
Although lemon sharks are classified as "Near-Threatened" by the International Union for Conservation of Nature (IUCN), there are no management plans currently in place for this species.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
Following mating, female lemon sharks gestate developing young for 10-12 months, after which they give birth to a litter of 4-17 live pups. Young are typically 60-65 cm long at birth and these sharks grow throughout their lifetimes, at an average rate of 0.54 cm/year.
Development - Life Cycle: indeterminate growth
This animal poses only a minor threat to humans; there are only 10 recorded unprovoked lemon shark attacks (none fatal) on record in the International Shark Attack File.
Negative Impacts: injures humans (bites or stings)
Lemon shark meat has been marketed fresh, salted or frozen and their fins, in particular, are prized among Asian cultures for use in shark-fin soup. Liver oil from lemon sharks has been used for its vitamin content and its hide has been used as leather.
Positive Impacts: food ; body parts are source of valuable material; source of medicine or drug ; research and education
Lemon sharks are hosts to a variety of ectoparasitic copepod species, as well as several endoparasitic fluke and tapeworm species. It has also been found with attached remoras (Echeneis naucrates), or sharksuckers, which feed on scraps from feeding lemon sharks and can also help to keep infestations of dermal parasites in check.
Mutualist Species:
Commensal/Parasitic Species:
Lemon sharks feed on molluscs, crustaceans, and bony fish. Some examples of prey items include cowfish (Acanthostracion quadricornis), flathead mullets (Mugil cephalus), spot-fin porcupinefish (Diodon holocanthus), Atlantic guitarfish (Rhinobatos lentiginosus), spotted eagle rays (Aetobatus narinari), brown crabs (Cancer pagurus), red swamp crayfish (Procambarus clarkii), and southern stingrays (Dasyatis americana). Juveniles are known to feed on giant tiger prawns (Penaeus monodon) and shore crabs (Carcinus maenas).
Animal Foods: fish; mollusks; aquatic crustaceans
Primary Diet: carnivore (Piscivore , Eats non-insect arthropods, Molluscivore )
Lemon sharks inhabit the Nearctic region of the Atlantic Ocean, from the coast of New Jersey, USA to southern Brazil, the Caribbean, and the Gulf of Mexico. There have also been sightings of lemon sharks along the coasts of Senegal and the Ivory Coast in Africa. This species is also found in the eastern Pacific Ocean, from Baja California to Ecuador. Lemon sharks are migratory and are found in oceanic waters during migration, but tend to be found in coastal areas otherwise. Efforts are underway to learn more specifics of lemon shark migration through tagging and tracking.
Biogeographic Regions: nearctic (Native ); neotropical (Native ); atlantic ocean (Native ); pacific ocean (Native )
Lemon shark are most commonly found in shallow ocean waters (to depths of 90 m), in habitats including mangroves, coral reefs and enclosed bays. They have also been known to congregate around docks. These sharks may be found in brackish and freshwater as well, most typically in river mouths and sounds, though they do not typically venture deep into these areas. They can be found in the open ocean during migrations. Lemon sharks can adapt to low oxygen and shallow water environments and may be found resting on ocean bottoms.
Range depth: 0 to 90 m.
Habitat Regions: tropical ; saltwater or marine
Aquatic Biomes: pelagic ; benthic ; reef ; coastal ; brackish water
The longest recorded lifespan for the lemon shark in captivity is 25 years. Using size and growth rate information, individuals caught in the wild have been estimated at over 30 years old.
Range lifespan
Status: wild: 30 (high) years.
Range lifespan
Status: captivity: 25 (high) years.
The coloration of lemon sharks varies from dark olive to yellowish brown dorsally, with a lighter yellow underside; they have no conspicuous markings. These sharks are large and stocky, with blunt snouts that are shorter than the width of their mouths. The bottom teeth are triangular and narrow with smooth-edged cusps, while the upper teeth are more broad and have smooth cusps and serrated bases. Teeth become more oblique as they near the corners of the mouth. They have two dorsal fins, with the posterior fin being shorter than the anterior, and paired pectoral and pelvic fins. This species is sexually dimorphic, with females being larger than males (averaging 240 cm vs 225 cm, respectively, though larger individuals have been found).
Range mass: 183.7 (high) kg.
Range length: 240 to 368 cm.
Other Physical Features: ectothermic ; bilateral symmetry
Sexual Dimorphism: female larger
While adult lemon sharks may occasionally eat juveniles, there are no known predators of adult lemon sharks.
Known Predators:
Mating occurs during the spring months, and is followed by a period of gestation for 10-12 months. It is likely that females store sperm from multiple mates to allow sperm competition, as a recent study showed that many lemon shark litters exhibit multiple paternity, indicating that this species is polyandrous. Mating is generally accomplished by a male biting a female on the pectoral fin and inserting his clasper (sexual organ) into her cloaca; recently mated females exhibit "mating wounds" from this behavior.
Mating System: polyandrous
Lemon sharks breed seasonally, typically during the spring and summer months. These sharks are viviparous and give birth to litters of 4-17 pups. Gestation period is 10-12 months and there is some evidence that, after producing a litter, females take a year off before mating again. Each time they give birth, female lemon sharks return to the same nursery areas. Juveniles remain in shallow waters of the nursery area, likely to avoid predators and have easy access to shore-line prey, for 2-3 years. They do not typically leave these safe areas until they have reached at least 90 cm in length and are less vulnerable. There is not much known beyond this regarding how and when juveniles leave for open waters and adult habitats, although there is evidence that they remain nearby their nursery areas for a number of years.
Breeding interval: Lemon sharks breed once yearly.
Breeding season: Lemon sharks breed during spring and summer months.
Range number of offspring: 4 to 17.
Range gestation period: 10 to 12 months.
Range age at sexual or reproductive maturity (female): 6 to 7 years.
Range age at sexual or reproductive maturity (male): 6 to 7 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); viviparous ; sperm-storing
Following mating, there is parental involvement by male lemon sharks. Females gestate young for 10-12 months.
Parental Investment: female parental care ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female)
