PRISTIdae SAWfish

Sawfish or Carpenter sharks are a family of rays characterized by a long, narrow, flattened rostrum lined with sharp transverse teeth that look like a saw. They are known as some of the largest fish, reaching lengths of between 23 and 25 feet long. Large individuals may weigh as much as 1,102–1,323 pounds or possibly even more. There are old unconfirmed and highly questionable reports of much larger individuals that do exist, including one that reputedly had a length of 30 feet, another that had a weight of 5,300 pounds and a third that was 31 feet long and weighed 5,712 pounds. Sawfish have been known and hunted for thousands of years and play an important mythological and spiritual role in many societies around world. Their appearance is unique and whimsical and naturally promotes wonder and awe. They are found worldwide in tropical and subtropical regions in coastal marine and brackish estuarine waters, as well as freshwater rivers and lakes.

Sawfish should not be confused with sawsharks (order Pristiophoriformes) or the extinct sclerorhynchids (order Sclerorhynchiformes) which have a similar appearance.

Sawfishes are relatively slow breeders and the females give birth to live young. They feed on fish and invertebrates that are detected and captured with the use of their saw. They are generally harmless to humans but can inflict serious injuries when captured and defending themselves with the saw.

Once common, sawfish have experienced a drastic decline in recent decades, and the only remaining strong presence are in Northern Australia and Florida, United States. We see sawfish quite often here in Jupiter, Fl, when they range up to about 108 feet in depth.

Check out this interactive map courtesy of the Florida Museum, a University of Florida accredited resource. 

The five species are rated as Endangered or Critically Endangered by the IUCN. They are hunted for their fins for use in shark fin soup, use of parts as traditional medicine, their teeth and saw. They also face habitat loss. They are protected in Australia and here in the United States, and if caught and not released, there are hefty fines in place for punishment,

The most distinctive feature of sawfish is their saw-like rostrum with a row of whitish rostral teeth on either side of it. The rostrum is an extension of the chondrocranium, made of cartilage and covered in skin. The rostrum length is typically about one-quarter to one-third of the total length of the fish, but it varies depending on species, and sometimes with age and sex. The rostral teeth are not teeth that you and I are familiar with, but heavily modified dermal denticles. The rostral teeth grow in size throughout the life of the sawfish and a tooth is not replaced if it is lost.

In Pristis sawfish the teeth are found along the entire length of the rostrum, but in adult Anoxypristis there are no teeth on the basal one-quarter of the rostrum (about one-sixth in juvenile Anoxypristis). The number of teeth varies depending on the species and can range from 14 to 37 on each side of the rostrum. It is common for a sawfish to have slightly different tooth counts on each side of its rostrum, but usually this is a difference of about 3. In some species, females on average have fewer teeth than males. Each tooth is peg-like in Pristis sawfish and flattened and broadly triangular in Anoxypristis.

Sawfish have a strong shark-like body, a flat underside and a flat head with the nostrils and mouth on the underside. They have small eyes and behind each is a spiracle, which is used to draw water past the gills. The gill slits, five on each side, are placed on the underside of the body near the base of the pectoral fins. The position of the gill openings separates them from the sawsharks. Sawfish do not have barbels.

Pristis sawfish have a rough sandpaper-like skin texture because of the dermal denticles, but in Anoxypristis the skin is largely smooth.

There are about 88–128 small, blunt-edged teeth in the upper jaw of the mouth and about 84–176 in the lower jaw. These are not the sawteeth. They are arranged in 10–12 rows on each jaw.

Sawfish have two relatively high and distinct dorsal fins, wing-like pectoral and pelvic fins, and a tail with a distinct upper lobe and a variably sized lower lobe. There are no anal fins.

Sawfish lack a swim bladder, and like others in their subclass, they control their buoyancy with their liver. They have a skeleton consisting of cartilage and the males have claspers. Their small intestines contain an internal partition shaped like a corkscrew, called a spiral valve, which increases the surface area available for food absorption.