Instruct: Given a question, retrieve passages that can help answer the question.
Query: How long do sawfishes get?
Sawfishes, also known as carpenter sharks, are a family of rays characterized by a long, narrow, flattened rostrum, or nose extension, lined with sharp transverse teeth, arranged in a way that resembles a saw. They are among the largest fish with some species reaching lengths of about 7–7.6m (23–25ft).[2] They are found worldwide in tropical and subtropical regions in coastal marine and brackish estuarine waters, as well as freshwater rivers and lakes.[3]
The status of the two species of the Atlantic region, the smalltooth and largetooth sawfish, is comparable to the Indo-Pacific. For example, sawfish have been entirely extirpated from most of the Atlantic coast of Africa (only survives for certain in Guinea-Bissau and Sierra Leone), as well as South Africa.[3][105] The only relatively large remaining population of the largetooth sawfish in the Atlantic region is at the Amazon estuary in Brazil, but there are smaller in Central America and West Africa, and this species is also found in the Pacific and Indian Oceans.[106] The smalltooth sawfish is only found in the Atlantic region and it is possibly the most threatened of all the species, as it had the smallest original range (range c. 2,100,000km2 or 810,000sqmi) and has experienced the greatest contraction (disappeared from c. 81% of its original range).[4] It only survives for certain in six countries,[107] and it is possible that the only remaining viable population is in the United States.[97] In the United States the smalltooth sawfish once occurred from Texas to New York, but its numbers have declined by at least 95% and today it is essentially restricted to Florida.[108][109] However, the Florida population retains a high genetic diversity,[108] has now stabilised and appears to be slowly increasing.[81][109] A Recovery Plan for the smalltooth sawfish has been in effect since 2002.[100] It has been strictly protected in the United States since 2003 when it was added to the Endangered Species Act as the first marine fish.[110] This makes it is "illegal to harm, harass, hook, or net sawfish in any way, except with a permit or in a permitted fishery".[14] The fine is up to US$10,000 for the first violation alone.[14] If accidentally caught, the sawfish has to be released as carefully as possible and a basic how-to guide has been published.[14] In 2003 an attempt of adding the largetooth sawfish to the Endangered Species Act was denied, in part because this species does not occur in the United States anymore[110] (last confirmed US record in 1961).[106] However, it was added in 2011,[111] and all the remaining sawfish species were added in 2014, restricting trade in them and their parts in the United States.[36]
Sawfish fishing goes back several thousand years,[7] but until relatively recently it typically involved traditional low-intensity methods such as simple hook-and-line or spearing. In most regions the major population decline in sawfish started in the 1960s–1980s.[7][83][95] This coincided with a major growth in demand of fins for shark fin soup, the expansion of the international shark finning fishing fleet,[83] and a proliferation of modern nylon fishing nets.[95] The exception is the dwarf sawfish which was relatively widespread in the Indo-Pacific, but by the early 1900s it had already disappeared from most of its range, only surviving for certain in Australia (there is a single recent possible record from the Arabian region).[3][96] The saw has been described as sawfish's Achilles' heel, as it easily becomes entangled in fishing nets.[97] Sawfish can also be difficult or dangerous to release from nets, meaning that some fishers will kill them even before bringing them aboard the boat,[55] or cut off the saw to keep it/release the fish. Because it is their main hunting device, the long-term survival of saw-less sawfish is highly questionable.[98] In Australia where sawfish have to be released if caught, the narrow sawfish has the highest mortality rate,[66] but it is still almost 50% for dwarf sawfish caught in gill nets.[96] In an attempt of lowering this, a guide to sawfish release has been published.[99]
Sawfish are large to very large fish, but the maximum size of each species is generally uncertain. The smalltooth sawfish, largetooth sawfish and green sawfish are among the world's largest fish. They can certainly all reach about 6m (20ft) in total length and there are reports of individuals larger than 7m (23ft), but these are often labeled with some uncertainty.[2] Typically reported maximum total lengths of these three are from 7to 7.6m (23–25ft).[2] Large individuals may weigh as much as 500–600kg (1,102–1,323lb),[47] or possibly even more.[48][49] Old unconfirmed and highly questionable reports of much larger individuals do exist, including one that reputedly had a length of 9.14m (30ft), another that had a weight of 2,400kg (5,300lb), and a third that was 9.45m (31ft) long and weighed 2,591kg (5,712lb).[48]
In the Bissagos Islands off West Africa dancing dressed as sawfish and other sea creatures is part of men's coming-of-age ceremonies.[80][83] In Gambia the saws indicate courage; the more on display at a house the more courageous the owner.[83] In Senegal the Lebu people believe the saw can protect their family, house and livestock. In the same general region they are recognized as ancestral spirits with the saw as a magic weapon. The Akan people of Ghana see sawfish as an authority symbol. There are proverbs with sawfish in the African language Duala.[84] In some other parts of coastal Africa, sawfish are considered extremely dangerous and supernatural, but their powers can be used by humans as their saw retains the powers against disease, bad luck and evil.[84] Among most African groups consumption of meat from sawfish is entirely acceptable, but in a few (in West Africa the Fula, Serer and Wolof people) it is taboo.[83] In Asia sawfish are a powerful symbol in many cultures. Asian shamans use sawfish rostrums for exorcisms and in other ceremonies to repel demons and disease.[85] They are believed to protect houses from ghosts when hung over doorways.[4] Illustrations of sawfish are often found at Buddhist temples in Thailand.[81] In the Sepik region of New Guinea locals admire sawfish, but also see them as punishers that will unleash heavy rainstorms on anyone breaking fishing taboos.[8] Among the Warnindhilyagwa, a group of Indigenous Australians, the ancestral sawfish Yukwurrirrindangwa and rays created the land. The ancestral sawfish carved out the river of Groote Eylandt with their saw.[8][86] Among European sailors sawfish were often feared as animals that could sink ships by piercing/sawing in the hull with their saw (claims now known to be entirely untrue),[59] but there are also stories of them saving people. In one case it was described how a ship almost sank during a storm in Italy in 1573. The sailors prayed and made it safely ashore where they discovered a sawfish that had "plugged" a hole in the ship with its saw. A sawfish rostrum said to be from this miraculous event is kept at the Sanctuary of Carmine Maggiore in Naples.[4]
The only remaining stronghold of the four species in the Indo-Pacific region (narrow, dwarf, largetooth and green sawfish) is in Northern Australia, but they have also experienced a declined there.[4][69] Pristis sawfish are protected in Australia and only Indigenous Australians can legally catch them.[100][103] Violations can result in a fine of up to AU$121,900.[13] The narrow sawfish does not receive the same level of protection as the Pristis sawfish.[100][104] Under CITES regulations, Australia was the only country that could export wild-caught sawfish for the aquarium trade from 2007 to 2013 (no country afterwards).[21] This strictly involved the largetooth sawfish where the Australian population remains relatively robust, and only living individuals "to appropriate and acceptable aquaria for primarily conservation purposes".[21] Numbers traded were very low (eight between 2007 and 2011),[4] and following a review Australia did not export any after 2011.[21] Except for Australia, sawfish have been extirpated or only survive in very low numbers in the Indo-Pacific region. For example, among the four species only two (narrow and largetooth sawfish) certainly survive in South Asia, and only two (narrow and green sawfish) certainly survive in Southeast Asia.[3]
Unlike the largetooth sawfish ("P. pristis"), the only other sawfish in the Atlantic, the smalltooth sawfish has a leading edge of the dorsal fin that is placed roughly above the leading edge of the pelvic fins (when the sawfish is seen from above or the side), relatively short pectoral fins and lack of a distinct lower lobe to the tail (lower lobe very small or absent). It can be separated from the more similar dwarf sawfish ("P. clavata") and green sawfish ("P. zijsron") by the distribution (both are only found in the Indo-Pacific) and the dorsal fin (its leading edge is placed slightly or clearly behind the leading edge of the pelvic fins in the dwarf and green sawfish). The smalltooth sawfish has a relatively narrow rostrum ("saw") with 20–32 teeth on each side.
The knifetooth sawfish ("Anoxypristis cuspidata"), also known as the pointed sawfish or narrow sawfish, is a species of sawfish in the family Pristidae, part of the Batoidea, a superorder of cartilaginous fish that includes the rays and skates. Sawfish display a circumglobal distribution in warm marine and freshwater habitats. Their extant biodiversity is limited to five species belonging to two genera (Pristis and Anoxypristis). The sawfishes are characterised by the long, narrow, flattened rostrum or extension on their snout. This is lined with sharp transverse teeth, arranged in a way that resembles the teeth of a saw. It is found in the shallow coastal waters and estuaries of the Indo-West Pacific, ranging from the Red Sea and the Persian Gulf to southern Japan, Papua New Guinea and northern Australia. It is the only living member of the genus Anoxypristis, but was previously included in the genus "Pristis". Compared to that genus, "Anoxypristis" has a narrower rostral saw with numerous teeth on the distal part and no teeth on the basal one-quarter (toothless section about one-sixth in juveniles). This endangered species reaches a length of up to .
The pregnancy lasts several months.[33] There are 1–23 young in each sawfish litter, which are 60–90cm (2–3ft) long at birth.[3][33] In the embryos the rostrum is flexible and it only hardens shortly before birth.[33] To protect the mother the saws of the young have a soft cover, which falls off shortly after birth.[64][65] The pupping grounds are in coastal and estuarine waters. In most species the young generally stay there for the first part of their lives, occasionally moving upriver when there is an increase in salinity.[50][55][56][66] The exception is the largetooth sawfish where the young move upriver into freshwater where they stay for 3–5 years, sometimes as much as 400km (250mi) from the sea.[58] In at least the smalltooth sawfish the young show a degree of site fidelity, generally staying in the same fairly small area in the first part of their lives.[67] In the green and dwarf sawfish there are indications that both sexes remain in the same overall region throughout their lives with little mixing between the subpopulations. In the largetooth sawfish the males appear to move more freely between the subpopulations, while mothers return to the region where they were born to give birth to their own young.[68][69]
Sawfish have a strong shark-like body, a flat underside and a flat head. Pristis sawfish have a rough sandpaper-like skin texture because of the covering of dermal denticles, but in Anoxypristis the skin is largely smooth.[2] The mouth and nostrils are placed on the underside of the head.[2] There are about 88–128 small, blunt-edged teeth in the upper jaw of the mouth and about 84–176 in the lower jaw (not to be confused with the teeth on the saw). These are arranged in 10–12 rows on each jaw,[42] and somewhat resemble a cobblestone road.[43] They have small eyes and behind each is a spiracle, which is used to draw water past the gills.[44] The gill slits, five on each side, are placed on the underside of the body near the base of the pectoral fins.[43] The position of the gill openings separates them from the superficially similar, but generally much smaller (up to c. 1.5m or 5ft long) sawsharks, where the slits are placed on the side of the neck.[1][45] Unlike sawfish, sawsharks also have a pair of long barbels on the rostrum ("saw").[1][45]
Sawfish are primarily found in coastal marine and estuarine brackish waters, but they are euryhaline (can adapt to various salinities) and also found in freshwater.[2] The largetooth sawfish, alternatively called the freshwater sawfish, has the greatest affinity for freshwater.[54] For example, it has been reported as far as 1,340km (830mi) up the Amazon River and in Lake Nicaragua, and its young spend the first years of their life in freshwater.[21] In contrast, the smalltooth, green and dwarf sawfish typically avoid pure freshwater, but may occasionally move far up rivers, especially during periods when there is an increased salinity.[50][55][56] There are reports of narrow sawfish seen far upriver, but these need confirmation and may involve misidentifications of other species of sawfish.[57]
There are several research projects aimed at sawfish in Australia and North America, but also a few in other continents.[116] The Florida Museum of Natural History maintains the International Sawfish Encounter Database where people worldwide are encouraged to report any sawfish encounters, whether it was living or a rostrum seen for sale in a shop/online.[4][14][81] Its data is used by biologists and conservationists for evaluating the habitat, range and abundance of sawfish around the world.[4] In an attempt of increasing the knowledge of their plight the first "Sawfish Day" was held on 17 October 2017.[82][117]
The Bahamas sawsharks ("Pristiophorus schroeder") have very little information on them. Studies are being done daily to learn more about the deep sea dweller. They are located near Cuba, Florida, and the Bahamas (hence their name) where they dwell in the depths of 400–1000 m. As far as their appearance they can be identified by their snouts with teeth which appear as a saw, as well as their length, they are averaged at 80 cm in length.
Saw sharks and sawfish are cartilaginous fish possessing large saws. These are the only two fish that have a long blade-like snout. Although they are similar in appearances, saw sharks are distinct from sawfish. Sawfish are not sharks, but a type of ray. The gill slits of the sawfishes are positioned on the underside like a ray, but the gill slits of the saw shark are positioned on the side like a shark. Sawfish can have a much larger size, lack barbels, and have evenly sized teeth rather than alternating teeth of the saw shark. Clear difference is that a sawfish has no barbels and a saw shark has a prominent pair halfway along the saw. The saw shark uses these like other bottom fish, as a kind of antennae, feeling the way along the ocean bottom until it finds some prey of interest. Both the saw shark and the sawfish utilize the electroreceptors on the saw, ampullae of Lorenzini, to detect the electric field given off by buried prey.
Relatively little is known about the reproductive habits of the sawfish, but all species are ovoviviparous with the adults females giving birth to live young once a year or every second year.[3] In general, males appear to reach sexual maturity at a slightly younger age and smaller size than females.[3] As far as known, sexual maturity is reached at an age of 7–12 years in Pristis and 2–3 years in Anoxypristis. In the smalltooth and green sawfish this equals a total length of 3.7–4.15m (12.1–13.6ft), in the largetooth sawfish at 2.8–3m (9.2–9.8ft), in the dwarf sawfish about 2.55–2.6m (8.4–8.5ft), and in the narrow sawfish at 2–2.25m (6.6–7.4ft).[3] This means that the generation length is about 4.6 years in the narrow sawfish and 14.6–17.2 years in the remaining species.[3]
Sclerorhynchiformes is an order of extinct batoids with long, serrated rostrums very similar to those of sawsharks and sawfishes. While they are neither, they are more closely related to sawfishes, and are included alongside them in the clade Pristiorajea.
The cultural significance of sawfish varies significantly. The Aztecs in what is currently Mexico often included depictions of sawfish rostra (saws), notably as the striker/sword of the monster Cipactli.[80] Numerous sawfish rostra have been found buried at the Templo Mayor and two locations in coastal Veracruz had Aztec names referring to sawfish.[4] In the same general region, sawfish teeth have been found in Mayan graves.[81] The saw of sawfish is part of the dancing masks of the Huave and Zapotecs in Oaxaca, Mexico.[4][82] The Kuna people on the Caribbean coast of Panama and Colombia considers sawfish as rescuers of drowning people and protectors against dangerous sea creatures.[8] Also in Panama sawfish were recognized as containing powerful spirits that could protect humans against supernatural enemies.[8]
The most distinctive feature of sawfish is their saw-like rostrum with a row of whitish teeth (rostral teeth) on either side of it. The rostrum is an extension of the chondrocranium ("skull"),[27] made of cartilage and covered in skin.[33] The rostrum length is typically about one-quarter to one-third of the total length of the fish,[5] but it varies depending on species, and sometimes with age and sex.[1] The rostral teeth are not teeth in the traditional sense, but heavily modified dermal denticles.[34] The rostral teeth grow in size throughout the life of the sawfish and a tooth is not replaced if it is lost.[34][35] 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).[36][37] The number of teeth varies depending on the species and can range from 14 to 37 on each side of the rostrum.[2][38][note 1] It is common for a sawfish to have slightly different tooth counts on each side of its rostrum (difference typically does not surpass three).[39][40] In some species, females on average have fewer teeth than males.[1][39] Each tooth is peg-like in Pristis sawfish, and flattened and broadly triangular in Anoxypristis.[2] A combination of features, including fins and rostrum, are typically used to separate the species,[2][38] but it is possible to do it by the rostrum alone.[41]
Adults are primarily found in estuaries and marine waters to a depth of , but mostly less than . Nevertheless, the species does appear to have a greater affinity for freshwater habitats than the smalltooth sawfish ("P. pectinata"), green sawfish ("P. zijsron"), and dwarf sawfish ("P. clavata"). Largetooth sawfish from the population in Lake Nicaragua appear to spend most, if not all, of their life in freshwater, but tagging surveys indicate that at least some do move between this lake and the sea. Captive studies show that this euryhaline species can thrive long-term in both salt and freshwater, regardless of its age, and that an acclimation from salt to freshwater is faster than the opposite. In captivity they are known to be agile (even swimming backwards), have an unusual ability to "climb" with the use of the pectoral fins and they can jump far out of the water; a individual jumped to a height of . It has been suggested that this may be adaptions for traversing medium-sized waterfalls and rapids when moving upriver. They are generally found in areas with a bottom consisting of sand, mud or silt. The preferred water temperature is between , and or colder is lethal.
The largetooth sawfish is easily recognized by the forward position of the dorsal fin with its leading edge placed clearly in front of the leading edge of the pelvic fins (when the sawfish is seen from above or the side), the relatively long pectoral fins with angular tips, and the presence of a small lower tail lobe. In all other sawfish species the leading edge of their dorsal fin is placed at, or behind, the leading edge of the pelvic fins, and all other "Pristis" sawfish species have shorter pectoral fins with less pointed tips and lack a distinct lower tail lobe (very small or none). The rostrum ("saw") of the largetooth sawfish has a width that is 15–25% of its length, which is relatively wide compared to the other sawfish species, and there are 14–24 equally separated teeth on each side of it. On average, females have shorter rostrums with fewer teeth than males. The proportional rostrum length also varies with age, with average being around 27% of the total length of the fish, but can be as high as 30% in juveniles and as low as 20–22% in adults.
The dwarf sawfish or Queensland sawfish, "Pristis clavata", is a sawfish of the family Pristidae, found in tropical Australia. This endangered species is by far the smallest species in its family.
The 2007 AFOI focussed on our imagined futures and how we might get there: a future with freedom from oppression, where we can live peaceably with our neighbours, on a sustainable earth, with decent work, a long life and a first-rate health care system to tend for us when our health falters. The big question was: how do we get there? How do we bequeath a better world for our children?
USS "Sawfish" (SS-276), a "Gato"-class submarine, was a ship of the United States Navy named for the sawfish, a viviparous ray which has a long flat snout with a row of toothlike structures along each edge. It is found principally in the mouths of tropical American and African rivers.
The dwarf sawfish is protected in Australian waters, but elsewhere in the world, sawfishes are harvested for their meat, fins, rostrums and oil. The main threat facing the dwarf sawfish is being caught as bycatch in gillnets and trawl nets. That this is the cause of declining numbers is demonstrated by the fact that populations are declining fastest in heavily fished areas. The International Union for Conservation of Nature has assessed the conservation status of this fish as "endangered". There is a need for education of fishermen about safe release practices and how to manage their fisheries. However, the threats are continuing, and there is no reason to believe that the population of dwarf sawfish is recovering from previous declines.5. (Sensory Systems in Sawfishes. 1. The Ampullae of Lorenzini) https://www.researchgate.net/profile/Barbara_Wueringer/publication/51559323_Sensory_systems_in_sawfishes._1._The_ampullae_of_Lorenzini/links/09e415091dacec5f51000000.pdf
Little is known of the breeding habits of the dwarf sawfish. The fish are ovoviviparous with the developing embryos feeding on the yolks of their eggs. It is not known how many young can be carried at one time nor how frequently the fish can breed, but the young are about long when they are born. Maximum longevity in this species is estimated to be forty-eight years.
The longcomb sawfish, narrowsnout sawfish or green sawfish ("Pristis zijsron") is a species of sawfish in the family Pristidae, found in tropical and subtropical waters of the Indo-West Pacific. It has declined drastically and is now considered a critically endangered species.