Sawfish and Guitarfish

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SAWFISH

sawfish
Sawfish are members of the shark and ray (elasmobranch) family and regarded as a ray. The have a long saw-like snout and body that looks like that of a cross between a ray and a shark. They sometimes reach seven meters (23 feet) in length, including the nearly two-meter (six-foot) snout and weigh up to 350 kilograms (770 pounds). Sawfish are fairly common in the Gulf of Mexico. In other places they endangered species and have been overfished and pulled up as bycatch and their saws have been harvested as souvenirs. Sawfish are generally not aggressive and are dangerous only of mishandled or harassed by divers.

Sawfish (Order:Rhinopristiformes, Family: Pristidae) are also known as carpenter sharks but should not be confused with sawsharks (order Pristiophoriformes) or swordfish (family Xiphiidae) which have a similar name but a very different appearance. Sawfishes are among the largest fish and are found worldwide in tropical and subtropical regions in coastal marine and brackish estuarine waters, as well as freshwater rivers and lakes. All species are endangered. [Source: Wikipedia]

Sawfish are extraordinary described as "hedge trimmers with fins". They .occur in shallower inshore freshwater and tropical marine areas around the world, reaching maximum depths of only 400 feet. Sawfish have gills on their underside, do not lose and replace their teeth like sharks. Sawfish can be quite large. Some species reach maximum length near seven meters (23 feet).

Websites and Resources: Animal Diversity Web (ADW) animaldiversity.org; National Oceanic and Atmospheric Administration (NOAA) noaa.gov; Fishbase fishbase.se ; Encyclopedia of Life eol.org ; Smithsonian Oceans Portal ocean.si.edu/ocean-life-ecosystems ; Woods Hole Oceanographic Institute whoi.edu ; Cousteau Society cousteau.org ; Monterey Bay Aquarium montereybayaquarium.org ; MarineBio marinebio.org/oceans/creatures

Sawfish Characteristics and Feeding

Although sawfishes have shark-like bodies, they are actually a type of ray. They are named after their "saws" (rostra) — long, flat snouts edged with teeth. The sawfish diet generally consists of a variety of fish, though molluscs and crustaceans (crabs and shrimp) may also be consumed. Like the way sailfish and marlin use their bills, the use their rostra to slash through schools of fish, swinging it from side to side to impale and stun prey..[Source: NOAA]

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The "saw" (rostra) is flat extension of the snout, covered with tough skin called “shagree”. It has two edges with about 25 pairs of long, sharp teeth. The snout can reach a length of six feet and a foot wide at the base. The saw is used primarily to slash prey in the water as described above or dig up food in sand and mud. Their rostra also contain electro-sensory organs, which can sense the weak amount of electricity produced by other animals. These organs help sawfish identify when prey is nearby

Mongabay reported: Sawfish are believed to use their iconic snouts for hunting. Not only does the long snout help the animals sense electrical signals from prey in murky water or under substrate, but its embedded teeth also allow the animal to strike and stun fast-moving prey. Based on observations, sawfish are believed to use their snouts in self-defense. They have also been reported to use their “saws” to cut pieces from larger prey. Other anecdotes include stories from Indian fishermen who purportedly observed sawfish attack and kill foraging dugongs, and an account in a paper from 1938 purporting a man was fatally wounded by a sawfish encounter. However, in general, sawfish are not regarded as dangerous to humans. [Source: Chris Samoray, Mongabay, April 16, 2014]

Sawfish Species

There are five species of sawfishes. Largetooth sawfish and smalltooth sawfish are the two species of sawfish that have historically inhabited U.S. waters, though largetooth sawfish have not been found in the United States in more than 50 years. Both are listed as endangered under the Endangered Species Act

The smalltooth sawfish is found in the Indo-pacific region and the eastern and western Atlantic. It has 24 to 32 pairs of pointed teeth on either use of its snout, which makes up 30 percent of its body length. It has a flattened head, small eyes and mouth and gills on the undersides of the head, It feeds by patrolling along the sea bed and suck up small organisms it encounters; sashes at schools of fish with it saw and feed on injured fish. It is found mostly in shallow water around beaches and bays but is occasionally in the mouths of river and freshwater streams.

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The Green sawfish (Scientific name: Pristis zijsron) weighs around 350 kilograms (770 pounds) has an average length of 4.6 meters (15 feet) and a lifespan of up to 50 years They are currently found primarily along the northern coast of Australia, but all sawfish species have undergone significant declines in Australian waters. The southern extent of the range of green sawfishes in Australia has contracted . They have been reported as far south as Sydney but are rarely found as far south as Townsville, Queensland (Porteous, 2004).[Source: NOAA]

The green sawfish is listed as endangered throughout its range under the Endangered Species Act.The main threats are habitat loss and entanglement in fish nets. Many islands within the Indo-Pacific region contain suitable habitat for sawfish, but few records are available, possibly due to the lack of surveys or data reporting. There is some evidence from the Persian Gulf and Red Sea (such as, Sudan) of small but extant populations

Largetooth Sawfish

The largetooth sawfish (Scientific name: Pristis pristis) can reach length of seven meters (23 feet) and live, depending on study, 35-80 years. It has the largest historical range of all sawfish species, but its populations have dramatically declined worldwide. The main threats are habitat loss, entanglement in fishing gear and low population growth [Source: NOAA]

Largetooth sawfish are brown on top and have a white underside. They have 14 to 24 teeth that are uniformly spaced on each side of their snout. The rostrum is more robust than that of other sawfish species and tapers from the base of the head to the anterior tip. The first dorsal fin begins well in advance (anteriorly) of the pelvic fin origins and the caudal fin has a distinct lower lobe.

Largetooth sawfish participate in sexual reproduction and fertilization is internal. They are yolk-sac viviparous meaning their young are attached to yolk sacs that nourish the embryo inside the mother's body and emerge as fully developed pups. The length of the female gestation period, or pregnancy, is believed to be 5 months and females can give birth every other year. Pups are born with their rostrum and rostral teeth fully developed, but it is very flexible and sheathed in a thick gelatinous material to avoid injuring the mother at birth (the sheath dissolves quickly thereafter). A mother largetooth sawfish can have 1 to 13 pups per litter. Newborn sawfish are approximately 76-90 centimeters (2.5 to 3 feet long) at birth and grow 33-38 centimeters (13 to 15 inches) in the first year. Largetooth sawfish reach sexual maturity around 8 to 10 years when they’ve reached a size of about three meters (10 feet).

Threats to Largetooth Sawfish

Largetooth sawfish are listed as endangered throughout their range according to Endangered Species Act (ESA, U.S. Fish and Wildlife): The Convention on International Trade in Endangered Species (CITES) places them in Appendix I, which lists species that are the most endangered.

Though affected by a variety of threats, habitat loss and bycatch mortality remain the largest threats to the existence of this species. Habitat alteration for mining, lumber, agriculture, and urbanization have reduced the quality and quantity of coastal and riverine habitat needed by largetooth sawfish. Given the largetooth sawfish’s dependence on freshwater areas as nursery habitat, changes to river flow and level have implications for juvenile survival. This potentially affects areas in which sawfish can give birth and juveniles can survive.[Source: NOAA]

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Sawfish are accidentally caught in a number of fishing gears, particularly gill nets, trawls, and hook and line tackle. Because sawfish have the potential to damage fishing gear and pose a threat to fishermen, they are often killed rather than being released unharmed. The high value of their fins in Asian markets and rostra for use in cultural ceremonies provides further incentive for retaining captured sawfish. Despite it’s endangered status, this species continues to be killed in both recreational and commercial fisheries throughout its range.

Largetooth sawfish were historically found in tropical and subtropical waters of all oceans around the globe. This included the Indo-Pacific region (Australia and southeast Asia to eastern Africa), the eastern Pacific (Mexico south to Peru), the western Atlantic (Gulf of Mexico south to Brazil), and the eastern Atlantic (Namibia to Mauritania). However, they are now considered extirpated or extremely rare in portions of their former range. The largest remaining population of largetooth sawfish is found in Australia, Amazonia, and the Indo-Pacific region. Largetooth sawfish may be found ranging between saline coastal waters and freshwater lakes or billabongs far upriver. Neonates are generally found in very shallow freshwater environments where they can avoid predation. As largetooth sawfish grow they expand their activity spaces and tend to use more marine coastal habitats.

Seriously Endangered Sawfish

Sawfish are among the most endangered fish in the sea, a study published in 2021 said.. The BBC reported: Once found along the coastlines of 90 countries, the animals are now presumed extinct in more than half of these. They are vanishing due to habitat loss and entanglement in fishing nets, experts have said. Their "saws", which evolved to sense and attack prey, have now become a liability, making them prone to being caught up in fishing gear. "Through the plight of sawfish, we are documenting the first cases of a wide-ranging marine fish being driven to local extinction by overfishing," said Prof Nick Dulvy of Simon Fraser University (SFU) in British Columbia, Canada. [Source: Helen Briggs, BBC, 12 February 2021

Of the five species of sawfish, three are critically endangered, while two are listed as endangered, according to the International Union for Conservation of Nature's (IUCN) Red List of Threatened Species. Previously widespread, the sawfish are now presumed extinct in 55 nations, the study said. There are 18 countries where at least one species of sawfish is missing, and 28 more where two species have disappeared. The list of countries where sawfish are extinct now includes China, Iraq, Haiti, Japan, Timor-Leste, El Salvador, Taiwan, Djibouti and Brunei.

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The US and Australia appear to be the last strongholds for the species, regarded as "lifeboat nations," where sawfish are better protected. The study, published in Science Advances, also identified eight nations where urgent action could make a big contribution to saving the species through conservation efforts. These are Cuba, Tanzania, Colombia, Madagascar, Panama, Brazil, Mexico and Sri Lanka. "While the situation is dire, we hope to offset the bad news by highlighting our informed identification of these priority nations with hope for saving sawfish in their waters," said Helen Yan of SFU.

She said it is still possible to restore sawfish to more than 70 percent of their historical range, "if we act now". International trade in sawfish is prohibited under the Convention on International Trade in Endangered Species of Flora and Fauna, but targeted and accidental killings still occur. Sawfish fins and teeth are sold as trophies, food or medicine, and as spurs for cockfighting. Sonja Fordham, a researcher of the study and president of Shark Advocates International, said there were opportunities to "bring these extraordinary animals back from the brink". But she warned that in too many places, "we're running out of time to save them".

Guitarfish

The Guitarfish (family Rhinobatos) is an ornery but relatively harmless shark with a shovel-shaped snout that sometimes butts divers like a ram. These sharks, which are quite tasty when they are young, are captured by divers who grab them by their tails and haul them out of the water.

The guitarfish is another member of the cartilaginous fish, ray and skate family that includes sawfish. All guitarfishes have a moderately depressed, elongated, shark-like body form, two equal, well-developed, and well-separated dorsal fins, and an elongated, wedge-shaped snout. Female common guitarfish give birth to live young in shallow waters during August and November.

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The shovelnose guitarfish (Scientific name: Rhinobatos productus) is a species found in the eastern Pacific. It reaches a length of 1.5 meters (five feet) and a weight of 18 kilograms (40 pounds. It has a broad head and clear, cartilaginous areas on either side its snout, wide ray-like pectoral fins, and a body that is otherwise like that of a shark. It is often found in shallow water in and around beaches, bays and estuaries where it lies partially buried in the sand or mud and feeds on small bottom-dwelling fishing, crustaceans or worms that it uncovers.

The common guitarfsh (Scientific name: Rhinobatos rhinobatos) weighs up to 28 kilograms (59 pounds), reaches lengths of up to 1.8 meters (6 feet) and have a lifespan of up to 24 years. They are listed as threatened by the Endangered Species Act (ESA, U.S. Fish and Wildlife) throughout their range. Among the main threats are commercial and subsistence fishing. [Source: NOAA]

The common guitarfish is brown on top and white underneath. It eats fish and invertebrates, such as mollusks and crustaceans and lives in shallow, sandy and muddy bottom habitats. It occurs in the Atlantic Ocean, from southern France to Angola. In the Mediterranean Sea, it occurs primarily along the southern and eastern coasts, in the waters of Tunisia, Turkey, Israel, Egypt, Lebanon, Syria, and Libya. The species is no longer found in the northern Mediterranean.

The common guitarfish once occurred in shallow waters throughout the Mediterranean Sea and eastern Atlantic Ocean, from France to Angola. It no longer occurs in many areas of the Mediterranean, and it is rare in West Africa. They are commercially fished to supply the shark fin trade in China and southeastern Asia. . Subsistence fishing of them supplies meat to growing coastal populations. The blackchin and Brazilian guitarfish are also listed under the Endangered Species Act.[Source: NOAA]

Guitarfish have accounted for one non-fatal shark attack and 0 fatal attacks for of total of 1 attacks. [Source: International Shark Attack Files, Florida Museum of Natural History, 2023]

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Image Sources: Wikimedia Commons; YouTube, Animal Diversity Web, NOAA

Text Sources: Animal Diversity Web (ADW) animaldiversity.org; National Oceanic and Atmospheric Administration (NOAA) noaa.gov; Wikipedia, National Geographic, Live Science, BBC, Smithsonian, New York Times, Washington Post, Los Angeles Times, The New Yorker, Reuters, Associated Press, Lonely Planet Guides and various books and other publications.

Last Updated March 2023

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