[6] The taxonomy of Pristis pristis in relations to P. microdon (claimed range: Indo-West Pacific) and P. perotteti (claimed range: Atlantic and East Pacific) has historically caused considerable confusion, but evidence published in 2013 revealed that the three are conspecific, as morphological and genetic differences are lacking.

[13] An individual caught in 1951 at Galveston, Texas, which was documented on film but not measured, has been estimated to be of similar size.

[4][21] The largetooth sawfish can be found worldwide in tropical and subtropical coastal regions, but it also enters freshwater and has been recorded in rivers as far as 1,340 km (830 mi) from the sea.

[1] There are old reports (last in the late 1950s or shortly after) from the Mediterranean and these have typically been regarded as vagrants,[1][11] but a review of records strongly suggests that this sea had a breeding population.

[1][4] Its total distribution covered almost 7,200,000 km2 (2,800,000 sq mi), more than any other species of sawfish, but it has disappeared from much of its historical range.

[4][6] Breeding is seasonal in this ovoviviparous species, but the exact timing appears to vary depending on the region.

[15] The adult females can breed once every 1–2 years, the gestation period is about five months,[1] and there are indications that mothers return to the region where they were born to give birth to their own young.

[1][4] They are likely typically born in salt or brackish water near river mouths, but move into freshwater where the young spend the first 3–5 years of their life,[1][6][17] sometimes as much as 400 km (250 mi) upriver.

[4] In the Amazon basin the largetooth sawfish has been reported even further upstream,[1][29] and this mostly involves young individuals that are up to 2 m (6.6 ft) long.

[12][27] As suggested by the alternative name common sawfish, it was once plentiful, but has now declined drastically leading to it being considered a critically endangered species by the IUCN.

[32] In the Niger Delta region of southern Nigeria, sawfish (known as oki in Ijaw and neighbouring languages) are traditionally hunted for their saws, which are used in masquerades.

[1] Other places in the Indo-Pacific where still present, even if in very low numbers, are off Eastern Africa, the Indian subcontinent and Papua New Guinea, and in the East Pacific it survives off Central America, Colombia and northern Peru.

[11][34] Whether it survives anywhere in Southeast Asia is generally unclear,[11] but one was captured in the Philippines in 2014 (a country where otherwise considered extirpated).

[14] It was once abundant in Lake Nicaragua (part of the San Juan River system), but this population rapidly crashed during the 1970s when tens of thousands were caught.

[36] In West Africa, the Bissagos Archipelago has often been considered the last remaining stronghold,[14] but interviews with locals indicate that sawfish now also are rare there.

[14] Additionally it receives a level of protection in Bangladesh, Brazil, Guinea, India, Indonesia, Malaysia, Mexico, Nicaragua, Senegal and South Africa, but illegal fishing continues, enforcement of fishing laws is often lacking and it has already disappeared from some of these countries.