Sawfish or Sawshark—How are they Different?

A photo of the smalltooth sawfish I dived with in March off the port of Miami. This photo was taken by my dive buddy Rebecca Ross of Miami Dade DERM

by Hunter Noren

After reading Dave Grant's article, "Vanishing Sawfish “, in our last newsletter, several members asked me how tell sawfish and sawsharks apart.

Well, for a start, both are elasmobranch fishes, but a sawfish is a ray with gills on its underside, while a sawshark is a ray with gills on its sides like other sharks. Both have thousands of electroreceptors (Ampullae of Lorenzini) in their snouts which they use to find prey and navigate. Both use their toothed saws as weapons to cut down and incapacitate prey with side-to-side movements. And both species spend most of their time on the seabed although sawfish prefer coastal waters, while sawsharks are usually in deeper waters.

The most obvious difference is their size: sawfish can grown to a length of more than 20 feet and weigh more than 1,200 pounds, but a really large sawshark is around five feet in length and weighs perhaps 20 pounds. Their saws are very different too: The saw of a sawfish is rimmed with teeth of equal size, while the saw of sawsharks is lined with teeth of varying sizes from large to small.

There are eight species of sawsharks: sixgill sawshark, Pliotrema warreni; longnose sawshark, Pristiophorus cirratus; tropical sawshark, Pristiophorus delicatus; Japanese sawshark, Pristiophorus japonicus; southern sawshark, Pristiophorus nudipinnis; Bahamas sawshark, Pristiophorus schroederi. There are also the newly discovered kaja's six-gilled sawshark, Pliotrema kajae, and Anna's six-gilled sawshark, Pliorema annae, found off the coasts of Zanzibar and Madagascar. Pliotrema kajae sp. nov. differs from P. annae sp. nov. in a longer snout, more numerous large lateral rostral teeth and upper jaw tooth rows, jaw teeth with (vs. without) sharp basal folds, and coloration, particularly pale to light brown (vs. medium to dark brown) dorsal coloration with (vs. without) two indistinct yellowish stripes.

For a Revision of the sixgill sawsharks, genus Pliotrema (Chondrichthyes, Pristiophoriformes), with full descriptions of two new species and a redescription of P. warreni, go to: https://doi.org/10.1371/journal.pone.0228791

There are five recognized species of sawfishes living worldwide today: the narrowtooth sawfish, Anoxypristis cuspidate; the green sawfish, Pristis zijsron; the dwarf sawfish, and Pristis clavata. Two other species are found in U.S. waters: the largetooth sawfish, Pristis pristis, which is limited to the Gulf of Mexico; and the smalltooth sawfish, Pristis pectinata, that is now only found along the Atlantic and Gulf coasts of Florida. Since 2003, the U.S. has listed the smalltooth sawfish as endangered. There has been a ban on inshore fishing nets in Florida waters for more than a decade and there are prohibitions and fines against intentionally capturing, harming or harassing sawfish.