Sawfish

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Sawfish images (Pristidae ) - stock photos showing this large ray with a distinctive saw-like snout

Scientific classification | Kingdom: Animalia > Phylum: Chordata > Class: Chondrichthyes > Subclass: Elasmobranchii > Superorder: Batoidea > Order: Rhinopristiformes > Family: Pristidae > Genera: Anoxypristis, Pristis

Sawfish are extremely large shark-like rays, related to both sharks and rays, belongs to family Pristidae, that inhabit muddy shallows of tropical bays, rivers and lakes. Like sharks and rays, the sawfish has a cartilaginous skeleton and no swim bladder. Instead they rely on a huge yellow, oil-filled liver to give them buoyancy. Their common name comes from their distinctive saw-like snout, called a rostrum, which has protruding teeth-like denticle scales, and is covered with sensitive pores that detect movement and even buried prey on the ocean floor. The eyes of sawfish are undeveloped due to their muddy habitat. The rostrum is the main sensory device.

Sawfish eat only small fish and bottom-dwelling invertebrates, like crabs and shrimps. Sawfishes are nocturnal, spending much of the day in the muddy floor. At night, they slowly swim through the shallows, using their sensitive rostrum to find buried prey, which are then raked from the sediment. The sawfish attacks its prey with its saw until the prey is small enough to eat. The saw is also used to defend the sawfish against predators. Sawfish live to around 25 years and reach maturity at 10 years. The smallest sawfish, dwarf sawfish, Pristis clavata, is about four feet long. The largest species, largetooth sawfish, Pristis microdon, and the southern sawfish, Pristis perotteti, reach more than 23 feet long. After many years of incidental capture, and habitat destruction, sawfish populations worldwide are severely depleted. They are hunted for their rostrum, their fins, their liver oil and for use as medicine. It is estimated that there are seven living species. Sawfish mature slowly and reproduce at a much lower rate than most fish. This makes sawfish especially slow to recover from overfishing. All species of sawfish are considered critically endangered and international trade is banned.

Sawfish live in tropical and sub-tropical areas around Africa and Australia and in the Caribbean, in rivers, bays and estuaries. Their color typically is light grey or brown. The smalltooth sawfish, Pristis pectinata, is olive green. They mate every other year, with an average litter of around eight pups, born live. A rubbery envelope surrounds the soft saw of fetal sawfish to protect the rostrum. Just before birth, the rostrum hardens and the sheath protects the mother during birth. This sheath then dissolves to allow the young sawfish to hunt.
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