Brazilian sharpnose shark

Lore & Background

The name Rhizoprionodon has Latin origin, translating to 'root saw tooth,' referring to the rooted, serrated teeth of sharks in this genus. The species name lalandii honors naturalist, taxidermist and explorer Pierre Antoine Delalande. The Brazilian sharpnose shark is characterized by a slender fusiform body, grayish-brown dorsal and white underside, relatively large eyes, a long snout, an inferior mouth, and a heterocercal caudal fin with a black edge tracing the tail's profile. It possesses dermal denticles and a nictitating membrane, like all Carcharhinidae. It may be confused with the Atlantic sharpnose shark (Rhizoprionodon terraenovae), which has similar size and coloration but a different distribution.

Females tend to be slightly larger than males. In northeastern South America, mating likely occurs between March and June, with births between December and March; in southeastern waters, births may occur between July and September. The species is viviparous, giving live birth. Primary and secondary nurseries often occur in the same area. The shark feeds primarily on teleosts (demersal and pelagic) and squid; juveniles also eat crustaceans, sciaenids, and clupeids. Research indicates it may be an important predator of demersal and pelagic prey.

Reader's Guide

The Brazilian sharpnose shark is significant as a commonly caught species in artisanal fisheries across South America, where its flesh is eaten after being dried and salted. Its fins are not used because they are too small. The species is listed as vulnerable by the IUCN, with numbers in decline, but it may actually classify at a higher level. Threats include intensive fishing, water pollution from plastic litter, and entanglement in plastic rings around the head or gills—three specimens have been found with such collars. In one study, plastic pellets were found in 22% of sampled R. lalandii specimens. Persistent organic pollutants (POPs) have also been found in the livers of juveniles, with coastal sharks like this one likely having higher contamination than deeper-water species. Conservation is complex because protecting the species must be balanced with the livelihoods of local fishers who rely on its abundance. The overall abundance is data deficient, though the species is caught frequently, indicating higher frequency in some areas.

Did You Know?

• The Brazilian sharpnose shark can reach a length of 77 cm.
• Three specimens have been found with plastic collars on their head or gills.
• The species name lalandii honors naturalist and explorer Pierre Antoine Delalande.