1. Biology and Ecology of a Sawfish

2. Taxonomy Phylum: Chordata
Class: Chondrichthyans (sharks, rays and chimeras)
Subclass: Elasmobranchii
Superorder: Batoidea (rays)
Order: Pristiformes
Family: Pristidae

3. Biology Life history strategy K-selected life history strategy
Long-lived
25-30 years
Large size
Up to 7m
Late sexual maturity
Approx. 10 years old
Low fecundity
8-24 pups

4. Distribution and Habitat
Global distribution in tropical and sub-tropical regions
Distribution is currently fragmented with most populations thought to be depleted
Occur in marine, freshwater and coastal habitats
Tolerance to freshwater dependent on species
Preference for shallow, inshore coastal and freshwater habitats but can occur to at least 80 m depth

5. Description
Closely related to rays with modified bodies similar to sharks
Also similar to and often confused with sawsharks
Distinguished by presence of gills on the underside of head

6. Behaviour Sawfish are nocturnal Sawfish are top order predators
Sleep in the day
Hunt at night
Sawfish are top order predators
Actively seek out prey items such as
Fish
Crustaceans
Squid
Use rostrum for feeding by
Stunning slow moving schooling fish with slashing motion
Locating and dislodging prey buried in sand or mud
Locate buried prey by using sensors on rostrum
Will also eat dead prey and strike at lures

7. Anatomy Rostrum can also be used to; Rostrum
rake through sediment to find prey
Stun prey with slashing motion
Protect from predators
Also used to distinguish species
Number of teeth
Shape of rostrum
Rostrum
Most distinguishing feature
Long flat and saw-like
Made of cartilage
Contains pairs of teeth on sides
Modified scales
Used to detect and catch prey using motion and electro- sensors
Allow detection from long distance and under sediment

8. Anatomy Eyes Spiracle On top of head so can see when partially buried
Eyesight good but often not useful due to murky habitat
Make up for this with sensitive sense organs in rostrum
Spiracle
Located behind the eye
Used to take in water when lying on the bottom

9. Anatomy
Dorsal
Dorsal means back or upper surface
2 dorsal fins
Used for stabilisation
Pelvic
Pair of pelvic fins located on side behind the pectoral fins
Used for stabilisation while swimming
Caudal
Also known as the tail fin
Shape differs between species
Used to generate power and speed in swimming
Fins
The sawfish has 4 different types of fins all with different uses
Pectoral
Pair of pectoral fins located behind the head
Used to lift fish when swimming
Helps with steering
Consists of cartilage spread out in fan shape
Does not reach edge of fin
Makes fin pliable increasing manoeuvrability

10. Anatomy Pelvic Dorsal Caudal
Pair of pelvic fins located on side behind the pectoral fins
Used for stabilisation while swimming
Caudal
Also known as the tail fin
Shape differs between species
Used to generate power and speed in swimming
Dorsal
Dorsal means back or upper surface
2 dorsal fins
Used for stabilisation

11. Anatomy Internal Anatomy Underside of Sawfish
Sawfish don’t contain swim bladder for buoyancy
Instead have an oil filled liver like sharks and rays
Underside of Sawfish
Like rays the flat ventral or underside of sawfish contain
Nostrils (nares)
Mouth
Gill slits
Jaw contains thousands of dome shaped teeth
Used to crush small fish and crustaceans e.g. Crabs and shrimp

12. Reproductive Biology Reproduce through internal fertilisation
Male contain claspers
Modification of pelvic fin
Used to insert sperm into female
Ovoviviparous
Eggs are fertilised and grow within mother
Hatch within womb and mother gives birth to fully developed pups

13. Reproductive Biology Average of 8 pups are born at around 65-90cm
Gestation period (fertilisation to birth time) is approx. 5 months
Number and size of pups increase with maturity of birthing mother
Pups born with a toothed rostrum which is covered by a enclosed membrane designed to protect mother from teeth
Growth rate
Rapid in first year of life
Slows considerably as maturity reached

14. Threats to sawfish

15. Saw fish are threatened throughout the world
All Australian species are on the IUCN Redlist of threatened species as critically endangered
Because they prefer an inshore benthic habitat for breeding ,the juveniles are vulnerable to human interference
They are also known to actively seek out dead baits or strike at lures making them vulnerable to recreational fishing

16. Major threats include Hunting Habitat modification and pollution
Entanglement in fishing nets

17. Hunting Sawfish are hunted for their
Rostrums
Fins
Flesh
Other body parts
These are sold for food and use in traditional Asian medicines
Rostrums are sold as valuable souvenirs, trophies or curios
Sawfish may also be collected as live specimens for aquariums

18. Habitat modification and pollution
Building of weirs and barrages can restrict movement of sawfish in rivers
Other problems include increased pollution from:
Land clearing - increased sediment runoff
Use of fertilisers - increased nutrient runoff
Use of pesticides - reduced health and death of organisms
Urban and industrial development
Loss of soft bottom feeding and breeding habitats also poses a threat

19. Entanglement in fishing nets
Sawfish are vulnerable to entanglement as the rostrum is easily entangled in nets and fishing line
The sawfish thrashes around to get free causing further tangling
When unable to swim the sawfish is unable to move water over gills and may drown
Entanglement may occur in
Trawling nets
Shark nets
Recreational fishing line