The sawfish is the common name for a family of rays, called Pristidae, containing seven species within two genera. Also known as the carpenter shark, it is not related to the similar looking sawshark. Sawfish prefer to live in the tropical or subtropical regions of the Indo-Pacific and Atlantic. Its largest populations are found in Australia and in Florida. This species can be found living near the coast in estuaries and bays, and can often be found moving into rivers or large lakes, like Lake Nicaragua. Every species of sawfish is able to travel into freshwater or saltwater, and will only live in shallow, murky water.
The sawfish derives its common name from the saw like rostrum that protrudes from its face. The rostrum serves many purposes, including defense and digging for crustaceans. It is covered in sensitive pores that give it the ability to easily locate food that is moving across the sea floor. Once prey is found, the sawfish will injure or stun it by slashing with its rostrum. The rostrum, or nose, bares sharp structures resembling teeth, although these are actually denticles. The sawfish is typically brown or pale gray in color, although the smalltooth sawfish can appear to be jade green in color.
Like all rays, the sawfish has a flat body with the eyes and mouth located on the underside. The mouth holds sharp teeth that are used to crunch up food like crustaceans and small fish. Occasionally the sawfish will swallow its prey without chewing it. Instead of having a swim bladder, which allows most fish to float, the sawfish uses its oil-filled liver to regulate buoyancy. This is common to rays, skates, and sharks. Its skeleton is composed of cartilage, and its eyes are not well developed, leaving the rostrum to be its main sensory organ.
The sawfish is nocturnal, spending the day resting on the sea floor and the night moving about and hunting. Little is known about its reproductive habits, but it is though that it can mate up to one time every two years, producing an average of eight live young. Young mature slowly, reaching sexual maturity at ten to twelve years of age.
The taxonomy of the sawfish is considered unorganized, because the classifications only include living species, leaving remains of possible species undescribed. One genus in the sawfish family, Pristis, contains the species Pristis pristis, Prisis microdon, and Pristis perotteti, which all needs review in order to be classified correctly.
The genus Anoxypristis holds only one species of sawfish, known as the knifetooth sawfish (Anoxypristis cuspidate). This saw fish is also known as the narrow sawfish or pointed sawfish. It ranges from The Red Sea and Persian Gulf to the southern waters of Japan, and into Papua New Guinea and northern waters of Australia. This species can reach an average length of up to fifteen feet appears on the IUCN Red List with a conservation status of “Critically Endangered”.
Within the genus Pristis, there are six species of sawfish, a few of which need taxonomic review. One of these is the largetooth sawfish (Pristis microdon). It is also known as the freshwater sawfish or Leichhardt’s sawfish, and can be found in the Indo-West Pacific. It is sometimes considered a synonym to P. perotteti, a sawfish that shares its genus. Because the location of the original specimen used to describe this species is unknown, more studies are needed to place it with P. perotteti. This species can grow to be twenty-three feet in length with a shorter saw shaped rostrum. It appears on the IUCN Red List with a conservation status of “Critically Endangered”.
Pristis perotteti, commonly known as the large-tooth sawfish, can be found areas of the Pacific and Atlantic, although it may be extinct in the eastern waters of the Atlantic. Its common name is very similar to that of P. microdon, a species with which it shares taxonomic confusion. It can grow to be twenty-one feet. Adults are typically found in estuaries, while young prefer to reside in freshwater. This sawfish appears on the IUCN Red List with a conservation status of “Critically Endangered”, and it is also slightly protected in U.S. waters by being listed as a Species of Concern by the U.S. National Marine Fisheries Service. More information is needed about it to place it under the U.S. Endangered Species Act.
The common sawfish (Pristis pristis) can be found in many areas including Australia, the eastern Pacific, the Atlantic, and the Mediterranean. It was once an abundant species, as its common name implies, but is now threatened. It is part of the species complex containing P. perotteti and P. microdon, in which there is much confusion involved with classification. The common sawfish can reach an average body length of 8.2 feet, but can grow to be twenty-five feet. It appears on the IUCN Red List with a conservation status of “Critically Endangered”.
The smalltooth sawfish (Pristis pectinata) can be found in the tropical waters of the Atlantic. It has been reported in other areas, but these reports have been dismissed as sightings of other species of sawfish. It reaches an average body length of up to twenty-five feet. As is typical to all sawfish, the reproductive rate of the smalltooth sawfish is slow, and combined with limited habitat and the dangers of being caught in fishing nets, it has earned a place in the IUCN Red List as “Critically Endangered.” In its United States range, the Endangered Species Act protects it from being caught for fishing. It is also protected under Appendix I of the Convention on International Trade in Endangered Species.
The dwarf sawfish (Pristis clavata), also known as the Queensland sawfish, has a limited range that only includes the tropical waters of Australia. It is the smallest member of the entire sawfish family, reaching an average body length of 4.6 feet. It appears on the IUCN red List with a conservation status of “Critically Endangered”.
The longcomb sawfish (Pristis zijsron) can be found ranging from East Africa and the Red Sea to Papua New Guinea and to China in the north. Its southern range extends to New South Wales, Australia. It can reach an average length of twenty-four feet and appears on the IUCN Red List with a conservation status of “Critically Endangered”.
Every species of sawfish is listed on the IUCN Red List as “critically Endangered”, due to a highly fragmented range, a slow reproductive rate, and intended and unintended capture. It was once hunted for sport, and although this is illegal in the United States and Australia, it is occasionally still sought as a prize fish. Other threats include being caught for the fins and liver oil, which is used in traditional medicine practices. In Aztec culture, the sawfish was considered an “Earth monster”, and many Asian shamans used the saw-like rostrum as a tool in exorcisms to deter demons and disease. In German culture, the sawfish was the emblem for the U-69 submarine and the ninth U-Boat called Flotilla. It has also appeared in cartoons like Vicke Viking.
Shark fins have become a very popular delicacy in many cultures, and the fins of the sawfish are one of the most desired. Because of this, all sawfish have been placed under the protection of the Convention on International Trade in Endangered Species (CITES), which prevents international trade of any part of the ray. The exception to this is one of the Australian species, which is legal to trade alive if placing in a commercial aquarium. However, maintaining a sawfish in an aquarium is difficult, as it requires a varied habitat of both salt water and freshwater, and as a result, captive breeding for conservation purposes has proved unsuccessful.
In both Australia and the United States, the capture of any sawfish is illegal. However, the only sawfish that is illegal to sell the rostrum of in the U.S. is the smalltooth sawfish, which is protected under the Endangered Species Act. This has not made a huge difference in preventing the sale of the smalltooth sawfish rostrum, as anglers are not able to discern it from other species.
A group called NOAA Fisheries has proposed a petition to request the protection of all sawfish under the Endangered Species Act. This group has also created safe procedures to remove any sawfish caught in fishing nets. The NOAA collaborated with the IUCN to launch the Global Sawfish Conservation Strategy in 2012, gathering twenty-nine shark experts from eleven countries. The experts and conservation groups created a workshop that focused the education, research, and conservation efforts needed to save the sawfish family. These include the training of fishery employees in local sawfish habitats including Borneo, West Africa, and Brazil, as well as creating methods to aid authorities and anglers in discerning between sawfish species, which enables them to better identify sawfish parts in possible trading situations.
Image Caption: A Smalltooth sawfish (Pristis pectinata) swimming in the Ocean Voyager tank of the Georgia Aquarium on 23rd January, 2006. Credit: DAVID ILIFF/Wikipedia (CC BY-SA 3.0)