Negaprion acutidens
Silhouette: Margot Michaud · PhyloPic
In 3 days ~70% in a week ~90%
The sicklefin lemon shark (Negaprion acutidens) or sharptooth lemon shark is a species of requiem shark belonging to the family Carcharhinidae, widely distributed in the tropical waters of the Indo-Pacific. It is closely related to the better-known lemon shark (N. brevirostris) of the Americas; the two species are almost identical in appearance, both being stout-bodied sharks with broad heads, two dorsal fins of nearly equal size, and a plain yellow-tinged coloration. As its common name suggests, the sicklefin lemon shark differs from its American counterpart in having more falcate (sickle-shaped) fins. This large species grows up to 3.8 m (12 ft) long. It generally inhabits water less than 92 m (302 ft) deep in a variety of habitats, from mangrove estuaries to coral reefs.
A slow-moving predator feeding mainly on bony fishes, the sicklefin lemon shark seldom travels long distances and many individuals can be found year-round at certain locations. Like other members of its family, this species is viviparous, with females giving birth to no more than 13 pups every other year, following a gestation period of 10–11 months. Although they are potentially dangerous to humans and known to respond vigorously to any provocation, under normal circumstances, sicklefin lemon sharks are cautious and tend to retreat if approached. The IUCN has assessed this species as Endangered; its low reproductive productivity and rate of movement limits the capacity of depleted stocks to recover. Off India and Southeast Asia, this species has been severely depleted or extirpated by unregulated exploitation for its meat, fins, and liver oil. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Ningaloo Marine Park | 🇦🇺 Australia |
More parks will be added in future updates.
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | Tianjin Zoo | 🇨🇳 China | |
| 2 | Ocean Park Aquarium | 🇦🇺 Australia | |
| 3 | Aquarium de Vannes | 🇫🇷 France |
Possible
About 30% of wildlife watchers report a Sicklefin Lemon Shark sighting in Ningaloo Marine Park on a given day, based on 20 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 9th most-seen of the 24 sharks and rays we can rate there. Over three days the chance rises to about 70%, and over a week to about 90%, if each day is a fresh chance.
March, May and September
In those months about 50% of wildlife watchers report a Sicklefin Lemon Shark in Ningaloo Marine Park on a given day, against under 5% in August, the lowest month. Those are among Ningaloo Marine Park's wettest months, with about 25 mm of rain a month against almost none in October.
Between 9 am and noon
Across all the parks we cover, that three-hour window holds the most Sicklefin Lemon Shark sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Only Ningaloo Marine Park, in our data
Ningaloo Marine Park is the only park on Wallace's Line with enough records to rate Sicklefin Lemon Shark sightings: about 30% of wildlife watchers there report one on a given day.
Same family: Carcharhinidae
The closest relatives of the Sicklefin Lemon Shark that you can see in Ningaloo Marine Park (family Carcharhinidae, Requiem Sharks) are Whitetip Reef Shark (about 60%), Blacktip Reef Shark (about 40%) and Gray Reef Shark (about 30%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Sicklefin Lemon Shark is recorded against all the sharks and rays logged in Ningaloo Marine Park (20 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
