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LARGETOOTH SAWFISH
Order - Pristiformes
Family - Pristidae
Genus - Pristis
Species - perotteti
Largetooth Sawfish

Taxonomy

The currently valid scientific name for the largetooth sawfish is Pristis perotteti (Müller & Henle, 1841). The genus name Pristis is derived from the Greek word "pristis" which means saw. The specific name perotteti is named after the French naturalist M. Perrottet who obtained the type specimens. A common synonym that has been used in past scientific literature is Pristis pristis Linnaeus 1758, which was taken probably not based upon any particular species of sawfish but rather treated sawfishes as a whole. Pristis microdon Latham 1794 has appeared as a misidentification and Pristis perrotteti as a misspelling. The taxonomy of the largetooth sawfish has been difficult to determine due to a lack of adult specimens, questionable identifications, and the number of synonyms that have been used in past scientific literature which remain to be resolved. Presently, there is difficulty in determining how many valid species within the genus Pristis actually exist.


Common Names

Common names for this species include largetooth sawfish, large-tooth sawfish, southern sawfish, common sawfish, freshwater sawfish, sawfish, saw fish (English); stortandet savrokke (Danish); billi sovulu, chakku thatte, naithatte (Kannada); makara sravu, vala sravu, velli sravi (Malayalam); hachutti meenu, shinesi (Telugu); iluppa, vela (Tamil); catanuda, pez espada, pez peine, pez rastrillo, pez sierra, sierra (Spanish); araguagua, peixe-serra (Portuguese); zaagvis, groottandzaagrog (Dutch); krarien, and sartji (Sranan).


Geographical Distribution

The largetooth sawfish (P. perotteti) and its close relative the smalltooth sawfish (P. pectinata) are the only two sawfish species to be found in the western Atlantic Ocean. Both species once covered a wide range of habitats, stretching over the tropical and sub-tropical marine environments, as well as estuarine and contiguous freshwater habitats in the eastern Atlantic Ocean from the Caribbean to Central and South American as well as Africa. In the United States largetooth sawfish were once reported throughout the Gulf of Mexico primarily along the Texas and east Florida coastline, in shallow coastal habitats less than 10 m (33 feet deep) where the water was warmer, shallower, more likely to be protected from the elements, such as lagoons or estuarine locations. However, migrations accounts reported them as traveling as far North as New York, and certainly along the Atlantic coast to the Carolinas before the decline of their population. A sizeable populationn of freshwater largetooth sawfish also lived in Lake Nicaragua, although by 1981 these sawfish had been drastically depeleted by overfishing. Today, the decline of the largetooth sawfish population seems to have mostly removed them from Florida's waters. The current reports of largetooth sawfish encounters are rare, and pin their location to the Texas coast close to the Louisiana line, and Southeastern United States waters seem to be the northernmost boundary of current populations, as compared to their historically freer range, although they are believed to also reside in Central America and some Western African coastal locations.


map
World distribution map for the largetooth sawfish


Habitat

Sawfish in general inhabit the shallow coastal waters in tropical, subtropical and warm-temperate waters. They are typically found very close to shore lying on muddy and sandy bottoms, in bays, estuaries, and lagoons. Generally thought to rarely descend to depths greater than 33 feet (10 meters ), sawfish have been found in water to 400 feet (122 meters) deep in Lake Nicaragua.


Biology
Largetooth Sawfish
Largetooth sawfish side view without the rostral saw
Bigelow and Schroeder (1948) FNWA


Largetooth Sawfish dorsal view
Largetooth sawfish dorsal view
Bigelow and Schroeder (1948) FNWA
· Distinctive Features
While they swim much like sharks, sawfish are actually a species of ray. Included in the group of fishes known as elasmobranchs, sawfish have cartilaginous skeletons. The head is ventrally flattened with the mouth located underneath and the eyes positioned dorsally. Sawfish are able to breath while lying on the ocean floor by drawing water into their gills through large holes behind each eye, called spiracles. Their most distinctive feature is their long flat rostrum - "saw" - that is lined with rostral teeth along the margins. These "teeth" are set deeply in hard cartilage and do not grow back if the root becomes damaged.

Largetooth Sawfish saw
Largetooth sawfish rostral saw
Bigelow and Schroeder (1948) FNWA


saw comparison
Comparison of smalltooth sawfish saw on left and largetooth sawfish saw on right


The largetooth sawfish and the smalltooth sawfish (P. pectinata) are similar in appearance with overlapping ranges in the western Atlantic Ocean and parts of the eastern Atlantic Ocean. The two species can usually be differentiated by noting the number of teeth on one side of the rostrum. P. perotteti can have between 14-21 rostral teeth on one edge of the saw whereas P. pectinata usually has 23-34.

Largetooth Sawfish
Rostral saw of largetooth sawfish
© Cathleen Bester

These two species can also be distinguished by observing that in P. perotteti the first dorsal fin originates anterior to the pelvic fins while in P. pectinata the first dorsal fin originates along the same axis as the pelvic fins. The pectoral fins of P. perotteti are proportionally larger than those of P. pectinata. Furthermore, only P. perotteti has a distinct lower lobe on its caudal fin.


· Coloration
P. perotteti caught in saltwater are dark gray to golden brown in color. Freshwater specimens are mouse gray with red coloration around the back, lower sides, second dorsal, pelvic fins, and caudal sides. The first dorsal may have pale yellow coloration with a reddish rear tip. The reddish tint may be normal or a result of suffusion with blood below the skin.


Largetooth Sawfish dentition
Teeth from the rostral saw of a largetooth sawfish
Bigelow and Schroeder (1948) FNWA


·Dentition
The teeth of the largetooth sawfish are dome-shaped anteriorly with an obtuse cutting edge. These teeth are a bit larger than in the smalltooth sawfish, with about 12 functional rows in each jaw. The number of teeth increases as the sawfish matures. Newborn largetooth sawfish have 70 teeth and larger individuals have approximately 80-90.


Largetooth Sawfish denticles
Denticles from below the first dorsal fin of a largetooth sawfish
Bigelow and Schroeder (1948) FNWA


·Denticles
Dermal denticles of P. perotteti are more widely spaced over the upper surface than in P. pectinata. The blades are ovoid in shape and rather strongly oblique. The bases are roughly four-cornered and are evident through the skin in very young specimens but more concealed in larger specimens. The denticles on the saw of P. perotteti are rounded to oval and are so closely crowded, they conceal the skin entirely. The denticles along the margins of this fish are the largest; those on lower surface are similar to those on the upper surface but are more closely crowded.


·Size, Age, and Growth
Maximum size of P. perotteti has been reported between 20.0-21.2 feet(6.1-6.5 m) total length and between 1,102-1,323 pounds (500-600 kg) in weight.

P. perotteti are believed to mature around 10 feet (3 m). Largetooth sawfish grow slowly, reaching maturity late at 10 years of age and producing few young. As a result, their population growth is extremely low. Although lifespan in the wild is unknown, research suggests this species lives roughly 30 years.


· Food Habits
Largetooth sawfish feed on benthic crustaceans and other invertebrates it stirs up from the substrate with its saw. The saw may also be used to disable prey by stunning small schooling fish such as mullet and smaller herrings before consuming them.


· Reproduction
P. perotteti is ovoviviparous. It's eggs are retained in the uterus and the embryos develop while being nourished by a yolk sac. The young are fully developed at birth and litters consist of 1-13 young with 7-9 being the most frequent litter size. Nicaraguan specimens have been recorded as 2.5 feet (76 cm) TL at birth. Litters may be produced every other year. The mating season for the Lake Nicaragua population of largetooth sawfish is early June to July, gestation lasts approximately five months, with young born from October to December. The sawteeth of young sawfish do not fully erupt, and are covered by a sheath of tissue until after birth to protect the mother during the birthing process.


American crocodile
The American crocodile is a predator of the largetooth sawfish
Everglades National Park Photo


· Predators
It has been reported that predators of the largetooth sawfish include the American crocodile (Crocodilus acutus). Sawfishes (Pristis spp.) have been preyed upon by narrowtooth sharks (Carcharhinus brachyurus), bull sharks (Carcharhinus leucas), and tiger sharks (Galeocerdo cuvier). Sawfishes may also fall victim to red tides. Red tide (Karenia brevis) is a local phenomenon in the Gulf of Mexico, along the Florida coast, and impacts many species of fish and wildlife.


largetooth saw
Largetooth sawfish saws have long been used by humans in a variety of purposes



Importance to Humans

Worldwide, sawfish saws have long been sold as trophies or curios. Historical uses of sawfish products have included the rostra being used in religious offerings and traditional medicine. The rostral teeth of the sawfish have been hand crafted into tools or attached to the legs of fighting birds used in cockfights. Sawfish meat has been harvested for human consumption and is reported to be white and tender. Today, sawfish fins are more valuable than the meat and have been sold in the Asian 'shark fin' trade. Some cultures believe tea made from the saws aid in treating asthma.


largetooth saw
Largetooth sawfish can use their saws for self defense
© Jason Seitz


Danger to Humans

Unprovoked, the sawfish is considered very docile. Captured sawfish should be handled with care however, as their saw can be used for defense in powerful side-to-side motions.


largetooth saw
Largetooth sawfish harvest


Conservation
Sawfish come into danger through the unique adaptation of the rostrum, which makes them vulnerable to incidental capture in fishing nets. Once caught, their saw becomes entangled in the netting and wraps them up, making it difficult to remove them without damage to the saw or to the fish. Their choice of habitats- shallow water near shores, and estuaries- also makes them susceptible to habitat degradation as more and more of these areas are destroyed or taken over by humans.

Beginning in 1992, sawfish have been protected by Florida law within state waters, with a ban on any fishing, both commercial and recreational. On April 1, 2003, the U.S. National Marine Fisheres Service plaed the smalltooth sawfish (P. pectinata) on the Endangered Species list, making it the first marine fish species to receive protection under the Endangered Species Act (ESA). The petition placed on behalf of the largetooth sawfish was declined for lack of substantial information about the species supporting their listing as an endangered species, despite the difficulty in obtaining such information from any largetooth sawfish populations both within the United States and in other geographically distinct populations.

The combined efforts of the NMFS and the Florida Program for Shark Research have produced new information on the largetooth sawfish and its status in Gulf waters, collecting both extensive historical accounts as well as data about current encounters. In March 2010, the largetooth sawfish was resubmitted for consideration as an "Endangered Species." The review found the species is in danger of extinction throughout its declinging range of habitats and should be listed as Endangered; however, despite the results of the review it was not listed at this time. In the July 2011 Federal Register, the NMFS issued at final determination to list the largetooth as endangered under the Endangered Species Act. As of July 21, 2011, the largetooth sawfish is officially listed as an endangered species under the Endangered Species Act of 1973.

The World Conservation Union (IUCN) declared the family Pristidae to be "among the most threatened elasmobranches" in the world with the largetooth sawfish currently listed as "Critically Endangered". The IUCN is a global union of states, governmental agencies, and non-governmental organizations in a partnership that assesses the conservation status of species. Additionally, in June 2007, the Convention on International Trade of Endangered Species (CITES) imposed sanctions for the protection of all sawfish species, making it internationally illegal to trade in sawfish, their rostrums, or their fins. The only trade of sawfish currently permitted is trade of live sawfish for public aquariums from Australia, in extremely limited quantities.




Prepared by:
Taylor Sullivan
Edited April 2012: Carmen Elenberger