Largetooth sawfish

A Largetooth sawfish

The **largetooth sawfish** (*Pristis pristis*), also known as the **common sawfish** (despite it being critically endangered in modern times), **wide sawfish**, **freshwater sawfish**, **river sawfish**, **Leichhardt's sawfish** (after explorer and naturalist Ludwig Leichhardt) and **northern sawfish**,is a species of sawfish in the family Pristidae. It is anadromous and is found in both salt and fresh water in tropical and subtropical regions worldwide.

## Description

The largetooth sawfish is reported to reach up to 7.5 meters (25 feet) in length, although the largest recorded was just under this size at 7 meters (23 feet) in length. An individual caught in Galveston, Texas was estimated to be roughly the same size. It was documented but never measured. Such large specimens can weigh between 1,100 and 1,300 pounds, some even in excess on this. Today, however, most individuals are much smaller, at 2-2.5 meters (6.6-8.2 feet) in length, and typically not exceeding 100 pounds in weight.

The rostrum typically accounts for around 27 percent of the animal's length, however, for juveniles, it can be up to 30 percent, and for adults, it can be as low as 20 percent. The rostrum typically has between 14 and 24 barbs.

The color of the animal's upperparts is typically somewhere from greyish-yellow to yellowish-brown. In most cases, there is a tannish hue, however, individuals in freshwater may have a reddish hue caused by blood suffusion below the skin. The underside is usually somewhere between very light grey and white.

## Distribution and Habitat

Largetooth sawfish are recorded living typically above depths of 10 meters (33 feet), however, they have been recorded reaching depths of 25 meters (82 feet). They have been recorded in multiple freshwater environments including the Amazon basin in South America, the Fitzroy River in Australia, and even into the southern United States. The population of Largetooth sawfish in Lake Nicaragua appear to spend most of their time in freshwater, and some believe that this population remains in the lake for their entire lives. On other occasions, Largetooth sawfish typically travel between fresh and salt water. The farthest up a river a Largetooth sawfish was recorded was around 830 miles.

Largetooth sawfish are typically found in temperatures between 24 and 32 degrees Celcius (75-90 Ferenheight). They are not believed to be able to survive in temperatures of 19 degrees Celcius (66 degrees Ferenhieght) or colder.

## Conservation

Largetooth sawfish are considered "Critically Endangered", most likely as a result of overfishing and habitat loss. Sawfish fins are commonly used in "Shark fin soup", a delicacy served primarily in Asia. Many species of Sharks, as well as Sawfish, are targeted for their fins. The rostrum is also of high value to some collectors.

Sawfish are exceptionally vulnerable to fishing nets because the barbs can easily become stuck. Many fishermen who bring in sawfish this way do not take the time to remove the net from the barbs, as this can greatly decrease the efficiency of the rest of the work. Largetooth sawfish have as a result of overfishing and habitat loss, declined significantly from all but 39% of their native range. The Australian population is perhaps the least affected of all of the remaining populations, and likely remains the largest and most viable breeding population.

Largetooth sawfish are the most common sawfish species in captivity and do fairly well in public aquaria due to their sedentary nature while attracting large crowds thanks to their size and fearsome appearances. According to aquarium studbooks, 16 individuals (10 males, 6 females) are kept in North American aquariums as of 2014, 5 individuals (3 males, 2 females) in European aquariums as of 2013, and 13 individuals (6 males, 7 females) in Australian aquariums as of 2017. Others are kept at public aquariums in Asia, but no count of captive sawfish in Asia is currently available.