Gestation
Ovoviviparous: embryos develop inside the female for about 5 months.
Four-stage life cycle
Sawfish
A remarkable fish with a long toothed rostrum
An elongated, shark-shaped ray, the sawfish uses its tooth-lined rostrum as an electric detector and a hunting weapon. It is one of the most endangered marine fish in the world.
Life cycle (4 stages)
Newborn
The pup is born alive, its rostrum folded and sheathed to protect the mother.
Juvenile
It grows for several years in estuaries and mangroves, sheltered from predators.
Adult
It moves to deeper coastal waters and matures at around 8 to 12 years.
Physical changes
- Flattened rostrum lined with rostral teeth, up to a quarter of the total length.
- Elongated ray body with ventral gill slits.
- Can exceed 5 metres in the largest species.
- Slow growth and low reproductive rate.
Habitat
- Estuaries
- Mangroves
- Shallow coastal waters
- Brackish bays
- Sometimes tropical rivers
Diet
- Small schooling fish
- Crustaceans
- Benthic molluscs
Survival adaptations
- Electroreceptors on the rostrum to detect buried prey.
- Rostrum used as a blade to stun schools of fish.
- Tolerance of brackish water, a refuge from predators.
- Flattened body allowing it to rest on the bottom.
Ecological importance
- Regulating coastal fish populations
- Indicating the health of mangroves and estuaries
- Maintaining brackish-zone biodiversity
Importance
- Type : Cartilaginous fish (Pristidae family, rays)
- Habitat shift : Internal gestation → Estuary and mangrove nurseries → Coastal waters → Breeding areas
- Role : Coastal predator and umbrella species of mangroves.
- All sawfish species are critically endangered: their rostrum tangles in nets and mangroves are disappearing.
Did you know?
The sawfish rostrum carries thousands of electroreceptors able to detect the heartbeat of a fish hidden under the sand.