Negaprion acutidens

Sicklefin lemon shark NGA
Characteristic features:

Dorsal surfaces uniform pale yellow to light brown or greyish. Fins without distinct markings, but may be black-edged. Ventral surfaces whitish.


Maximum size up to 310 cm TL; birth size 50–70 cm TL.


Found throughout the Indian and central Pacific in tropical waters.


Mostly found in bays, estuaries, mangrove stands, shallow sand and reef flats, and lagoons. Prefers turbid, still water. Found from the intertidal zone to depths of at least 90 meters depth.


Feeds primarily on bony fish and rays, but also crustacean and cephalopods. A relatively slow-swimming species that is shy and rarely approaches people; juveniles can be inquisitive. Movement studies have shown that juveniles have very restricted movements. Adults more active at night; juveniles often found in the intertidal zone during the day. Length at maturity is ~220 cm TL for both sexes. Reproductive mode is viviparous with yolk-sac placenta. Females give birth to 1–14 (average 9) pups after a gestation period of 10–11 months, breeding every second year. Maximum age reported as at least 9 and 7 years for females and males respectively.

Indonesian fisheries:

Rarely observed in Indonesian fish landings in recent times due to the very high level of exploitation of inshore waters and the slow growth rate of this species.

Similar species:

A distinctive species, but general body colour of live sharks similar to:

Carcharhinus melanopterus
Blacktip reef shark

Carcharhinus melanopterus

Carcharhinus melanopterus differs in having a second dorsal fin much smaller than the first (vs. first and second dorsal fins of similar size).

Rhizoprionodon spp.

Rhizoprionodon acutus
Rhizoprionodon acutus

Rhizoprionodon spp. differ in having second dorsal fin much smaller than first dorsal fin (vs. second dorsal fin nearly as large as first dorsal fin) and snout pointed, when viewed from underneath (vs. snout broadly rounded).

Glyphis gangeticus
Ganges shark

Glyphis gangetcisu differs in having a second dorsal fin smaller than first dorsal fin (vs. second dorsal fin nearly as large as first dorsal fin).

Triaenodon obesus
Whitetip reef shark

Triaenodon obesus

Triaenodon obesus differs in having expanded nasal flaps forming a tube (vs. nasal flaps not forming a tube and cusplets present on most teeth in both jaws (vs. no cusplets).

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