Sawfish

Description

Sawfish are part of the Rajiformes order—a group of flattened marine fish that include rays and skates—and are closely related to sharks. Two species of sawfish are found in U.S. waters: the wide or smalltooth sawfish (Pristis pectinata) and the largetooth sawfish (Pristis perotteti). Unlike the rest of the cartilaginous fishes, sawfish have evolved a long snout edged with special teeth. The sawlike snout, called a rostrum, can be used in a back-and-forth swiping motion to cut prey in half or to dig through the sediment. The largetooth sawfish can grow up to 23 feet (7 meters). A smalltooth sawfish averages 18 feet (5.5 meters) in length and may reach 25 feet (7.6 meters).

Range

Both U.S. species of sawfish occur in the Gulf of Mexico and along the borders of southern states. They are also found along South America, near the Gulf of California, and on the west coast of Africa.

Five other species of sawfish are found along the borders of the Indian Ocean, the northeastern part of Australia, and as far north as China and Japan. Sawfish prefer shallow, coastal waters and even swim into freshwater river systems.

Diet

Sawfish eat fish and crustaceans. The saw is key to catching and killing prey—in addition to its use as a weapon or digging tool, the saw has small pores that can detect electric fields produced by prey. This supersense is common to sharks and rays alike.

Life History

Sawfish are ovoviviparous, meaning that rather than laying eggs, females carry the young and give birth to a number of developed juvenile sawfish. Smalltooth sawfish reach reproductive maturity at 10 years old and usually live to 25 or 30 years. Longevity estimates are similar for the largetooth sawfish.

Conservation

The smalltooth sawfish is federally listed as endangered. Sawfish populations are likely declining due to overharvesting and entanglement in fishing gear, as their long, toothed rostrums become very easily entangled with fishing line and nets. The saws are dried and sold as trinkets in some cultures. Additionally, loss of mangrove forests and other nursery habitats in the Southeast for conversion to beachfront development contributes to the decline of sawfish. Recovery efforts are in effect to guide fishermen in the safe release of sawfish that are mistakenly caught. The establishment of marine protected areas and the banning of entangling fishing gear in Florida waters have helped to slow the decline of sawfish.

Fun Fact

Like many toothed fish, sawfish can replace their teeth if they are worn down or lost. This phenomenon is called polyphyodonty.

Sources

Office of Protected Resources, National Oceanic and Atmospheric Administration

National Geographic

The IUCN Red List of Threatened Species

U.S. Fish & Wildlife Service