Pristis pristis

The largetooth sawfish (Pristis pristis, syn. P. microdon and P. perotteti) is a species of sawfish in the family Pristidae. It is found worldwide in tropical and subtropical coastal regions, but also enters freshwater. It has declined drastically and is now critically endangered.

DESCRIPTION

• The largetooth sawfish possibly reaches up to 7.5 m (25 ft) in total length, but the largest confirmed was a West African individual that was 7 m (23 ft) long.

• The largetooth sawfish is easily recognized by the forward position of the dorsal fin with its leading edge placed clearly in front of the leading edge of the pelvic fins (when the sawfish is seen from above or the side), the relatively long pectoral fins with angular tips, and the presence of a small lower tail lobe.

• The rostrum ("saw") of the largetooth sawfish has a width that is 15–25% of its length, which is relatively wide compared to the other sawfish species, and there are 14–24 equally separated teeth on each side of it.

• On average, females have shorter rostrums with fewer teeth than males.

• The proportional rostrum length also varies with age, with average being around 27% of the total length of the fish, but can be as high as 30% in juveniles and as low as 20–22% in adults.

• Its upperparts are generally grey to yellowish-brown, often with a clear yellow tinge to the fins.

• Individuals in freshwater may have a reddish colour caused by blood suffusion below the skin.

• The underside is greyish or white.

DISTRIBUTION AND HABITAT

The large tooth 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.

Adults are primarily found in estuaries and marine waters to a depth of 25 m (82 ft), but mostly less than 10 m (33 ft).

BEHAVIOR AND LIFE CYCLE

• Sexual maturity is reached at a length of about 2.8–3 m (9.2–9.8 ft) when 7–10 years old.

• Breeding is seasonal in this ovoviviparous species, but the exact timing appears to vary depending on the region.

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

• There are 1–13 young in each litter, which are 72–90 cm (28–35 in) long at birth.

• 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, sometimes as much as 400 km (250 mi) upriver.

• Occasionally, young individuals become isolated in freshwater pools during floods and may live there for years.

• The potential lifespan of the largetooth sawfish is unknown, but four estimates suggested 30 years.

• The largetooth sawfish is a predator that feeds on fish, molluscs and crustaceans.

• The "saw" can be used both to stir up the bottom to find prey and to slash at groups of fish.

• Sawfish are docile and harmless to humans, except when captured where they can inflict serious injuries when defending themselves with the "saw".