The narrow sawfish (''Anoxypristis cuspidata''), also known as the pointed sawfish or knifetooth sawfish, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

sawfish Sawfish, 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 ...

in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Pristidae Sawfish, 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 ...

, part of the

Batoidea Batoidea is a superorder of cartilaginous fishes, commonly known as rays. They and their close relatives, the sharks, comprise the subclass Elasmobranchii. Rays are the largest group of cartilaginous fishes, with well over 600 species in 26 fa ...

, a superorder of cartilaginous fish that include the

rays Ray may refer to: Fish * Ray (fish), any cartilaginous fish of the superorder Batoidea * Ray (fish fin anatomy), a bony or horny spine on a fin Science and mathematics * Ray (geometry), half of a line proceeding from an initial point * Ray (gra ...

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 Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit * 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 ships * Ros ...

or extension on their snout. This is lined with sharp transverse teeth, arranged in a way that resemble the teeth of a saw and are used for killing prey. It is found in the shallow coastal waters and estuaries of the

Indo-West 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 ...

, ranging from the

Persian Gulf The Persian Gulf ( fa, خلیج فارس, translit=xalij-e fârs, lit=Gulf of Fars, ), sometimes called the ( ar, اَلْخَلِيْجُ ٱلْعَرَبِيُّ, Al-Khalīj al-ˁArabī), is a mediterranean sea in Western Asia. The bod ...

to southern Japan,

Papua New Guinea Papua New Guinea (abbreviated PNG; , ; tpi, Papua Niugini; ho, Papua Niu Gini), officially the Independent State of Papua New Guinea ( tpi, Independen Stet bilong Papua Niugini; ho, Independen Stet bilong Papua Niu Gini), is a country i ...

and northern Australia. It is the only living member of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

Anoxypristis, but was previously included in the

Pristis ''Pristis'' is a genus of sawfish of the family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maint ...

. Compared to Pristis, 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). It reaches a length of up to . In addition to the living Anoxypristis cuspidata, this genus includes a few extinct species that are only known from

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

remains.

Description

The narrow sawfish grows to a maximum length of about , although there are highly questionable and unconfirmed claims of much larger individuals. Its body is generally shark-like, but its most obvious feature is the flattened head, which is extended forward in a blade-like bony snout with, in Australian waters, 18 to 22 pairs of sideways-facing teeth. However, elsewhere there may be as many as 25. These teeth are short, flat, and roughly triangular in shape. The blade does not taper towards its point and in adults, the basal one-quarter is devoid of teeth. In juveniles, about one-sixth of the base is toothless. The nostrils are narrow and partially concealed by nasal flaps. The skin of young sawfish is smooth, but on older individuals, it is sparsely covered in dermal denticles. The dorsal (upper) side of the fish is greyish and the ventral (lower) side and fins are a pale grey color. The rostrum is grey with white teeth and sometimes has a chocolate-brown base portion.

Distribution and habitat

The Narrow Sawfish is distributed across a broad swathe of the Indo-Pacific Ocean. It is present in the waters off Iran, India, Sri Lanka, Bangladesh, Malaysia, Burma, Indonesia, and Papua New Guinea. At its western extreme, it is present in the

Arabian Sea The Arabian Sea ( ar, اَلْبَحرْ ٱلْعَرَبِيُّ, Al-Bahr al-ˁArabī) is a region of the northern Indian Ocean bounded on the north by Pakistan, Iran and the Gulf of Oman, on the west by the Gulf of Aden, Guardafui Channel ...

and may extend as far as

Somalia Somalia, , Osmanya script: 𐒈𐒝𐒑𐒛𐒐𐒘𐒕𐒖; ar, الصومال, aṣ-Ṣūmāl officially the Federal Republic of SomaliaThe ''Federal Republic of Somalia'' is the country's name per Article 1 of thProvisional Constituti ...

. Its northern limit is the

Gulf of Chihli The Bohai Sea () is a marginal sea approximately in area on the east coast of Mainland China. It is the northwestern and innermost extension of the Yellow Sea, to which it connects to the east via the Bohai Strait. It has a mean depth of a ...

, China, South Korea, and the most southerly parts of Japan, and its southern limit is the northern Australian states of Western Australia, the Northern Territory, and Queensland. The Narrow Sawfish is bentho-pelagic and is found at depths of about . The Narrow Sawfish prefers soft bottom-substrates, such as sand, mud, or seagrass, to rocky or coraline habitats. It can tolerate low salinity levels and is found in inshore waters, including bays and estuaries. The Narrow Sawfish is euryhaline, meaning it can tolerate a wide range of salinity and move between estuarine and marine environments. It undergoes an

ontogenetic Ontogeny (also ontogenesis) is the origination and development of an organism (both physical and psychological, e.g., moral development), usually from the time of fertilization of the egg to adult. The term can also be used to refer to the st ...

shift in habitat. Larger individuals are commonly found offshore, whereas smaller individuals are found inshore. Females are also more likely to be found offshore. The Narrow Sawfish is suspected to be locally extinct in the coastal waters of Vietnam due to commercial fishing (especially trawling), coastal development, and subsequent habitat loss.

Behavior

Reproduction and Life History

The breeding behavior of the Narrow Sawfish has been little studied. Fertilization is internal, and a number of young develop at one time in the

oviduct The oviduct in mammals, is the passageway from an ovary. In human females this is more usually known as the Fallopian tube or uterine tube. The eggs travel along the oviduct. These eggs will either be fertilized by spermatozoa to become a zygote, o ...

, each one being nourished from a

yolk sac The yolk sac is a membranous sac attached to an embryo, formed by cells of the hypoblast layer of the bilaminar embryonic disc. This is alternatively called the umbilical vesicle by the Terminologia Embryologica (TE), though ''yolk sac'' is ...

. Mating season varies by geographic region, and pups are born after a gestational period of about five months. Litter sizes range from 6 to 23 pups with an average of 12. The pups are usually 43 – 61 cm long at birth, and their rostral teeth are not fully developed, being covered by a membrane, which prevents them from damaging the mother's tissues. Only two studies have been conducted on the age and growth of the narrow sawfish. The longest lived narrow sawfish found was 9 years old. However, the theoretical longevity is calculated to be 27 years. Females begin to mature at 8 feet 1 inch total length and are fully mature at 15 feet 5 inches. Males are fully mature at 8 feet total length.

Temperament

The narrow sawfish is docile towards humans and not large enough to consider them as prey. If left undisturbed, it is harmless towards people. However, when highly stressed, such as when caught in a net, narrow sawfish will flail their heads from side to side to defend themselves. This can potentially inflict serious injury on unprotected persons who get too close.

Diet

The narrow sawfish feeds on small fish, squid, and invertebrates such as crabs and shrimp. It uses its rostrum in a side-to-side thrashing action to stir up the sediment and uncover concealed prey. It can also use its rostrum among schools of fish to incapacitate or stun individual fish. The head and rostrum of the sawfish contain thousands of electroreception organs called ampullae of lorenzini, which allow it to sense and locate the electric fields of its prey. The narrow sawfish is itself

prey Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...

to various sharks such as the

hammerhead shark The hammerhead sharks are a group of sharks that form the family Sphyrnidae, so named for the unusual and distinctive structure of their heads, which are flattened and laterally extended into a "hammer" shape called a cephalofoil. Most hammerhe ...

(Sphyrna spp.), the

bull shark The bull shark (''Carcharhinus leucas''), also known as the Zambezi shark (informally zambi) in Africa and Lake Nicaragua shark in Nicaragua, is a species of requiem shark commonly found worldwide in warm, shallow waters along coasts and in ri ...

(Carcharhinus leucas) and the

copper shark The copper shark (''Carcharhinus brachyurus''), bronze whaler, or narrowtooth shark, is a species of requiem shark, family Carcharhinidae, and the only member of its genus found mostly at temperate latitudes. It is distributed in a number of sepa ...

(Carcharhinus brachyurus) and also the

saltwater crocodile The saltwater crocodile (''Crocodylus porosus'') is a crocodilian native to saltwater habitats and brackish wetlands from India's east coast across Southeast Asia and the Sundaic region to northern Australia and Micronesia. It has been list ...

(Crocodylus porosus).

Conservation Status

Threats

Human actions are the main cause of the declining Narrow Sawfish populations and ranges. Overutilization, primarily from commercial fisheries, is its biggest threat. Narrow Sawfish populations have likely decreased between 50 and 70% over the last 20 years. The Narrow Sawfish is a high-value target for fishermen. Sawfish are commonly hunted to make shark fin soup or for their rostrums to be displayed as trophies. Most countries have regulations against catching it; however, illegal, unreported, and unregulated fishing remains a threat. Furthermore, the Narrow Sawfish is a common bycatch for fisheries in its geographic range. The toothed rostrum makes it vulnerable to most types of fishing gear, particularly nets. Damaged, neglected, or lost fishing gear (aka ghost nets) are also a considerable threat to Narrow Sawfish. Pregnant females and juveniles are at the highest risk for this threat. Additionally, the Narrow Sawfish has the highest post-release mortality of any sawfish species. Habitat loss and water pollution are also threats to the Narrow Sawfish. Coastal development, coastline urbanisation, and an expanding mining industry result in the modification and destruction of critical habitat. Furthermore, the pollution from these activities degrades the water quality. The Narrow Sawfish range is suspected to have declined by 30% from historic extent. These threats are expected to become more significant as the human population grows. Natural threats, such as disease and predation, do not significantly harm the Narrow Sawfish population.

IUCN Status

The IUCN listed the Narrow Sawfish as "

Endangered 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 and in ...

" in its

Red List of Threatened Species The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biologi ...

in the year 2000. This was due to the threats of overutilization, habitat loss, and a decreasing population. Its status was updated to “Critically Endangered” in 2006. In 2013, its status returned to “Endangered” due to the availability of new information.

ESA Listing

On September 10, 2010, WildEarth Guardians petitioned the US

National Marine Fisheries Service The National Marine Fisheries Service (NMFS), informally known as NOAA Fisheries, is a United States federal agency within the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) that is responsible for the ste ...

(NMFS) to list six sawfish species - the Narrow Sawfish; the Dwarf Sawfish, the Freshwater Sawfish, the Common Sawfish, the Narrowsnout Sawfish, and the

Smalltooth Sawfish The smalltooth sawfish (''Pristis pectinata'') is a species of sawfish in the family Pristidae. It is found in shallow tropical and subtropical waters in coastal and estuarine parts of the Atlantic. Reports from elsewhere are now believed to be m ...

- as endangered or threatened under the Endangered Species Act. The NMFS published a 90-day review on March 7, 2011, stating that action may be warranted for five of the six species. Information available at the time indicated that the Common Sawfish was not a valid species. On June 4, 2013, the NMFS published a proposal that concluded all five Sawfish species were at high risk for

extinction Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

. The proposal listed habitat loss, water quality, and overutilization as the biggest threats to the Narrow Sawfish. The NMFS published its final ruling on December 12, 2014, which listed all five Sawfish species as endangered. Scientific data showed that geographical areas occupied by the Narrow Sawfish were entirely outside U.S. jurisdiction. Therefore, the NMFS was not able to designate any critical habitat. Furthermore, the NMFS did not develop a recovery plan because they would not be able to enforce it.

Conservation Efforts

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

and

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , establishe ...

have listed protections for the Narrow Sawfish as a “no-take” species. Sawfish also are considered “no-take” species in India, but the legislation is frequently ignored and rarely enforced. International trade of the narrow sawfish has been banned by its inclusion in the

Convention on International Trade in Endangered Species of Wild Fauna and Flora CITES (shorter name for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of intern ...

(CITES) Appendix 1. Current population of the Narrow Sawfish is unknown.

References

External links

Species Description of Anoxypristis cuspidata at www.shark-references.com
{{Taxonbar, from=Q135965 knifetooth sawfish Marine fish of Africa Marine fish of Asia Fish of the Pacific Ocean Fish of the Red Sea Fish of Southeast Asia Fish of the Philippines Monotypic fish genera Ovoviviparous fish Endangered fish Endangered fauna of Asia Endangered biota of Africa knifetooth sawfish knifetooth sawfish ESA endangered species