Distribution, abundance and biology of the smalltooth sandtiger shark Odontaspis ferox (Risso, 1810) (Lamniformes: Odontaspididae)

Abstract

The smalltooth sandtiger shark, Odontaspis ferox, has a cosmopolitan distribution across warm temperate and tropical waters, and although essentially demersal, it has also been captured pelagically in mid-ocean. The species often occurs inshore at steeply shelving coastal and insular locations, and has now been identified by divers at eight widely separated shallow water sites. In the Southern Hemisphere, most O. ferox were caught by trawl on the continental slope, where its bathic range was extended to at least 880 m. Large specimens (>200 cm TL) were found across the whole depth range, but almost all juveniles were caught between 200 and 600 m. The largest recorded male was 344 cm TL, and female 450 cm TL. The few biological data suggest that size at maturity for males is around 200–250 cm TL, and for females 300–350 cm. No pregnant females were recorded but size at birth is probably about 100 cm TL. Nowhere has the species been found in large numbers. Survey and commercial catch data from south-east Australian trawl grounds suggest that numbers of O. ferox there have declined since the advent of deepwater commercial trawling in the 1970s. In areas of steep untrawlable terrain, increased gill-netting and longlining are likely to impact on local populations, with mature individuals being particularly vulnerable. Although O. ferox is not specifically targeted by commercial fishing activities, its likely very low fecundity make it susceptible to local extirpation, even at seemingly small capture rates. This species is protected off New South Wales and is considered “vulnerable” globally, by the World Conservation Union (IUCN).