The dwarf sawfish or Queensland sawfish, ''Pristis clavata'', is a

sawfish Sawfish, also known as carpenter sharks, are a family of very large 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 lar ...

of the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Pristidae Sawfish, also known as carpenter sharks, are a Family (biology), family of very large batoidea, rays characterized by a long, narrow, flattened rostrum (anatomy), rostrum, or nose extension, lined with sharp transverse plane, transverse teeth, ...

, found in tropical

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

. This

endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, inv ...

is the smallest species in its family.

Description

The dwarf sawfish has a torpedo-shaped body that resembles that of a shark, and grows to a length of about . It has broad, triangular pectoral fins and large, upright dorsal fins. The first dorsal fin is located directly above, or slightly behind, the origins of the pelvic fins, and the caudal fin has a very small lower lobe. The snout is broad and flat and is elongated into a

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit ** podium * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ...

with around twenty pairs of rostral teeth. The rostral teeth are rounded and lack the grooves seen in

Largetooth sawfish The largetooth sawfish (''Pristis pristis'', syn. ''P. microdon'' and ''P. perotteti'') is a species of sawfish in the family Pristidae. It is found worldwide in tropical and subtropical coastal regions, but also enters freshwater. It has declin ...

, and if present, they are very small and limited. This fish is usually greenish-brown, or occasionally yellowish-brown, on its dorsal surface, and whitish underneath.

Distribution and habitat

The dwarf sawfish is native to the western and central

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

region and historically had a much wider range than it does now. Its present confirmed range is from southern

New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; , fossilized , also known as Papua or historically ) is the List of islands by area, world's second-largest island, with an area of . Located in Melanesia in the southwestern Pacific Ocean, the island is ...

to the tropical region of northern

. A recorded sighting from the

Canary Islands The Canary Islands (; ) or Canaries are an archipelago in the Atlantic Ocean and the southernmost Autonomous communities of Spain, Autonomous Community of Spain. They are located in the northwest of Africa, with the closest point to the cont ...

was probably of a different species. It typically inhabits inshore waters, estuaries, tidal mudflats and sometimes the lowest reaches of rivers.

Ecology

This sawfish feeds mainly on fish, but also eats molluscs and crustaceans. The rostrum has large numbers of pores adapted for

electroreception Electroreception and electrogenesis are the closely related biological abilities to perceive electrical stimuli and to generate electric fields. Both are used to locate prey; stronger electric discharges are used in a few groups of fishes, such ...

and is probably also used to manipulate prey. Its sensory input helps the fish move about in the muddy waters in which it often lives. Although they are sometimes found in deep water, most movements take place while the tide is either rising or falling, and movements during each tidal cycle may be up to . At high tide the fish tend to forage and rest among the

mangrove A mangrove is a shrub or tree that grows mainly in coastal saline water, saline or brackish water. Mangroves grow in an equatorial climate, typically along coastlines and tidal rivers. They have particular adaptations to take in extra oxygen a ...

s. Little is known of the breeding habits of the dwarf sawfish. The fish are

ovoviviparous Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a "bridging" form of reproduction between egg-laying oviparity, oviparous and live-bearing viviparity, viviparous reproduction. Ovoviviparous animals possess embryos that develo ...

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.

Status

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 Bycatch (or by-catch), in the fishing industry, is a fish or other marine species that is caught unintentionally while fishing for specific species or sizes of wildlife. Bycatch is either the wrong species, the wrong sex, or is undersized or juve ...

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 The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...

has assessed the conservation status of this fish as "

critically endangered An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...

". 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. Due to the decrease in the number of individuals, this species is rarely stored in aquariums, and as of 2021, 2 individuals (1 male and 1 female) are in kept in the Japanese public aquarium

Aqua Park Shinagawa Maxell Aqua Park Shinagawa (Japanese language, ja: マクセルアクアパーク品川, ''Makuseru Akua Pāku Shinagawa''), formerly Epson Aqua Park Shinagawa, Epson Shinagawa Aqua Stadium is a public aquarium located inside the Prince Hotels, Sh ...

References

External links

* *
Species Description of Pristis clavata at www.shark-references.com
{{Taxonbar, from=Q244406

Pristis ''Pristis'' is a genus of sawfish of the family (biology), family Pristidae. These large fish are found worldwide in tropical and subtropical regions in coastal marine waters, estuaries, and Fresh water, freshwater lakes and rivers. Sawfish have ...