Where do sawfishes live?
1051355#27
The pregnancy lasts several months. There are 1–23 young in each sawfish litter, which are long at birth. In the embryos the rostrum is flexible and it only hardens shortly before birth. To protect the mother the saws of the young have a soft cover, which falls off shortly after birth. 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. The exception is the largetooth sawfish where the young move upriver into freshwater where they stay for 3–5 years, sometimes as much as from the sea. 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. 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.
Sawfish
1051355#23
The dwarf and largetooth sawfish are strictly warm-water species that generally live in waters that are and respectively. The green and smalltooth sawfish also occur in colder waters, in the latter down to , as illustrated by their (original) distributions that ranged further north and south of the strictly warm-water species. Sawfish are bottom-dwellers, but in captivity it has been noted that at least the largetooth and green sawfish readily take food from the water surface. Sawfish are mostly found in places with soft bottoms such as mud or sand, but may also occur over hard rocky bottoms or at coral reefs. They are often found in areas with seagrass or mangrove.
Sawfish
7106737#3
The longcomb sawfish is native to tropical and subtropical waters in the western and central Indo-Pacific. Historically its distribution covered almost and it ranged from South Africa, north to the Red Sea and Persian Gulf, east to the South China Sea, through Southeast Asia to Australia. In Australia, it ranged from Shark Bay, along the northern part of the country, and south to Jervis Bay on the eastern coast. Today it has disappeared from much of its historical range. It can live in colder waters than its relatives, as also evident by the range in Australia where it occurs further south than the other species of sawfish.
Longcomb sawfish
7106305#9
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.
Largetooth sawfish
1051355#21
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. The largetooth sawfish, alternatively called the freshwater sawfish, has the greatest affinity for freshwater. For example, it has been reported as far as up the Amazon River and in Lake Nicaragua, and its young spend the first years of their life in freshwater. 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. There are reports of narrow sawfish seen far upriver, but these need confirmation and may involve misidentifications of other species of sawfish.
Sawfish
1051355#22
Sawfish are mostly found in relatively shallow waters, typically at depths less than , and occasionally less than . Young prefer very shallow places and are often found in water only deep. Sawfish can occur offshore, but are rare deeper than . An unidentified sawfish (either a largetooth or smalltooth sawfish) was captured off Central America at a depth in excess of .
Sawfish
7106491#15
Smalltooth sawfish are extremely vulnerable to overexploitation because of their propensity for entanglement in nets, their restricted habitat, and low rate of population growth. The species is listed as critically endangered by the IUCN Red List. Historically it was found in 47 countries, but it has been extirpated from 16 and possibly extirpated from another 25, leaving only 6 countries where it certainly still survives. In terms of area this means that it certainly survives in only 19% of its historical range. It is the only sawfish that certainly still survives in the United States (the largetooth sawfish, "P. pristis", has likely been extirpated from this country), and it has been listed by the National Marine Fisheries Service as endangered under the Endangered Species Act since 2003. It is estimated that the smalltooth sawfish population in the United States now equals less than 5% of the historical population in this country. In the United States it once occurred from Texas to New York (northern range as summer visitors), but today it is essentially limited to Florida. In the Everglades region of Florida the population is now stable and possibly slowly rising. Other countries where it certainly survives are the Bahamas, Cuba, Belize, Honduras and Sierra Leone, but whether it survives in the Western Gulf of Mexico or off the Atlantic coast of South America is unclear. The species is listed on Appendix I of the Convention on International Trade in Endangered Species.
Smalltooth sawfish
255084#14
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.
Sawshark
1051355#0
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 . They are found worldwide in tropical and subtropical regions in coastal marine and brackish estuarine waters, as well as freshwater rivers and lakes.
Sawfish
7105663#0
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 .
Knifetooth sawfish
1051355#43
Sawfish are popular in public aquariums, but require very large tanks. In a review of 10 North American and European public aquariums that kept sawfish, their tanks were all very large and ranged from about . Individuals in public aquariums often function as "ambassadors" for sawfish and their conservation plight. In captivity they are quite robust, appear to grow faster than their wild counterparts (perhaps due to consistent access to food) and individuals have lived for decades, but breeding them have proven difficult. In 2012, four smalltooth sawfish pups were born at Atlantis Paradise Island in the Bahamas and this remains the only time a member of this family has been successfully bred in captivity (unsuccessful breeding attempts had happened earlier at the same facility, including a miscarriage in 2003). Nevertheless, it is hoped that this success may be the first step in a captive breeding program for the threatened sawfish. It is speculated that seasonal variations in water temperature, salinity and photoperiod are necessary to encourage breeding. Artificial insemination, as already has been done in a few captive sharks, is also being considered. Tracking studies indicate that if sawfish are released to the wild after spending a period in captivity (for example, if they outgrow their exhibit), they rapidly adopt a movement pattern similar to that of fully wild sawfish.
Sawfish