Smalltooth sawfish (Pristis pectinata)
|Also known as:||combshark, common sawfish, Florida sawfish|
|Spanish:||Pez Sierra, Sayyaf, Sayyafah|
|Size||Maximum length: 760 cm (2)|
Average length: 550 cm (3)
|Weight||350 kg (2)|
The smalltooth sawfish is classified as Critically Endangered (CR) on the IUCN Red List and as Endangered under the United States National Marine Fisheries Service (2).
The smalltooth sawfish gets its name from the Greek word ‘pristis’, meaning saw and the small teeth that line the edges of its saw, which are not as large as those of other members of the sawfish family. The sawfish has a flattened shark-shaped body, brown to bluish-grey in colour, with a white underside, and wing-shaped pectoral fins. The saw is a quarter of the total length of the body and has between 25 and 32 pairs of small, sharp teeth which are longer and less broad towards the end of the saw. The mouth is on the underside and contains 10 to 12 rows of teeth in both jaws. The upper side of the sawfish is covered in rough tooth-like scales, whereas the underside is coated in smooth tooth-like scales (2) (3).
The historical distribution of this species was worldwide, although recent declines in number mean that the smalltooth sawfish is now absent from many sites. In American waters, the smalltooth sawfish used to be prevalent in coastal areas from New York, around the Floridian peninsula and along as far as Texas (1) (2) (3).
The smalltooth sawfish can exist both in saltwater and freshwater, tending to prefer fairly shallow water with muddy or sandy bottoms such as rivers, streams, lakes, creeks, bays, lagoons, and estuaries. Although the smalltooth sawfish prefers depths of no more than 120 m, it will cross deep oceans to reach new areas of coastline (1) (2) (3) (4).
The sawfish uses its saw to catch prey in two ways; firstly by using it as a rake to sift through the sand for crustaceans such as crabs and shrimps, and secondly by using it as a sword to swipe through schools of shoaling fish such as mullet, lacerating or stunning individuals. The smalltooth sawfish is predated on by sharks, but only when it is young and undersized (2) (3).
Little is known about the life cycle of the smalltooth sawfish but it is thought to breed year round in areas of constant climate, but elsewhere, only in the summer. Fertilisation is internal and the pups develop inside the female, who gives birth a year later to 15 to 20 pups. The saws of the newborns are sheathed and malleable at birth for protection. The pups are around 60 cm long at birth (3) (4) (5).
The smalltooth sawfish has been over-fished both intentionally and as by-catch. Accidentally caught sawfish are rarely returned to the water alive as they are difficult to disentangle from nets and are dangerous to fishermen. Sawfish are purposefully caught for sport, for food and for their oil, which is used to make soap, medicine and for polishing leather, as well as for their saws which are removed and sold as curios. Habitat modification is also contributing to the decline of this species, which is slow to recover from population crashes due to slow maturation and a long reproductive cycle (1) (2) (3).
Florida has established three wildlife refuges to protect the habitat of the smalltooth sawfish and in the hope that numbers might increase sufficiently for re-colonisation of other areas (3). It has been protected from harvesting in Florida since 1992 and over the rest of American waters since 2003 (5). Research into smalltooth sawfish life-history and population distribution, as well as education and awareness initiatives, may help to prevent further decline of this species, but these efforts must be made worldwide to ensure the protection of this amazing fish (6).
For further information on the conservation of sharks and rays see:
- By-catch: in the fishing industry, the part of the catch made up of non-target species.
- Crustacea: diverse group of arthropods (a phylum of animals with jointed limbs and a hard chitinous exoskeleton) characterised by the possession of two pairs of antennae, one pair of mandibles (parts of the mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps, slaters, woodlice and barnacles.
- Pectoral fins: in fish, the pair of fins that are found one on each side of the body just behind the gills. They are generally used for balancing and braking.
IUCN Red List (May, 2006)
Fish Base (October, 2004)
Ichthyology at the Florida Museum of Natural History (October, 2004)
Elasmodiver (October, 2004)
The Florida Sawfish Site (October, 2004)
Status Review of the Smalltooth Sawfish (October, 2004)