Classification of Pristis (Saw Fish)

• Phylum :- Chordata (Dorsal tubular nerve cord, notochord and gill-slits present.)
• Group :- Craniata (Cranium with brain present.)
• Sub phylum :- Vertebrata (Vertebral column present.)
• Division :- Gnathostomata (Jaws and paired appendages present.)
• Super Class :- Pisces (Paired fins, gills and skin with scales.)
• Class :- Chondrichthyes (=Elasmobranchii) (Endoskeleton cartilaginous. Scales usually placoid. Notochord rudimentary, Spiral valve in intestine, opercula absent)
• Sub-Class :- Elasmobranchii (Sharks and rays, Gills in separate clefts, cloaca present)
• Order :- Rhinopristiformes (Gills-slits ventral, Spiracles Present, Dorsal Fin on tail, if present, Vertebrae tectospondylous.)
• Family :- Pristidae
• Genus :- Pristis

Geographical distribution

Pristis is found in tropical and sub-tropical regions. Indian form ascends beyond tidal zones. It is reported from America, Gulf of Mexico, Lower Mississippi, the Mediterranean sea and Atlantic waters. Upper Jurassic to Recent.

Habit and habitat

Pristis is a warm water marine type. It is predacious, feeding on small fishes and other marine animals by slashing them with its saw. It often ascends the river.

General Characteristics of Pristis (Saw Fish)

• Commonly called as saw-fish, weighing 350 to 1200 lbs and measuring 3 to 6 metres in length.
• Elongated, shark like body is slightly depressed and divided into head, trunk and tail.
• Body shape is midway between a shark and a ray.
• The anterior part is flattened dorsoventrally and is ray-like while the posterior part, for more than half, is shark-like.
• It exhibits close relationship with rays. Head contains a pair of eyes and a pair of spiracles behind the eyes.
• Water passes through the spiracles and goes out through the gill-slits.
• Snout is anteriorly produced into a saw-like rostrum with large and small weakly embedded teeth.
• Mouth is on the ventral side of the head. Tail is well developed and ends in a heterocercal caudal fin.
• Dorsal fins are large. First dorsal fin is opposite to pelvic fin. Second dorsal fin is called as adipose fin.
• Paired fins are pectoral and pelvic. Tail contains caudal fins.

Economic importance

The fish is also economically very beneficial as its liver oil is rich in vitamin value and its skin for making scale boards.

The Pristis fish, commonly known as the sawfish, has significant economic and ecological importance, primarily in fisheries, tourism, and as a part of the marine ecosystem. Here’s an overview:

• Fisheries and Trade Meat:
  • Sawfish meat is considered a delicacy in some regions and contributes to local food markets.
  • Fins: Their fins are valued for use in traditional dishes like shark fin soup, especially in Asia.
  • Oil and Byproducts: Sawfish liver oil is used in medicinal and industrial applications.
  • Rostrum (Saw): The distinctive saw-shaped rostrum is often sold as a decorative item or for use in traditional medicine.
• Ecotourism
  • Sawfish are a major draw for marine ecotourism, particularly in regions with thriving dive tourism industries. Observing sawfish in their natural habitats attracts tourists, contributing to local economies.
• Cultural Significance
  • In some cultures, the sawfish holds symbolic or spiritual importance, further influencing its economic value in artisan crafts and cultural events.
• Conservation and Research
  • Sawfish are critically endangered, making them a focus for conservation programs funded by governments and NGOs. These efforts can create jobs and economic opportunities in research, monitoring, and habitat restoration.

Challenges and Sustainability

The economic benefits of sawfish must be balanced with sustainable practices to ensure their survival. Overexploitation, habitat destruction, and bycatch have led to severe population declines. Conservation measures, such as marine protected areas and sustainable ecotourism practices, are vital for preserving this species while supporting economic benefits.

Special features

• The important structure is ‘saw-like’ snout, which is formed by the elongation of head and skull. They are flattened in the form of a rostrum, which contains a series of tooth-like 16 to 32 pairs of denticles on the lateral margins
• The teeth are fixed in sockets, in the calcified rostral cartilage
• The rostrum acts as an organ of offence and defence
• Pristis is capable for retaining urea in fresh-water while ascending in rivers.

Identification

Since this fish has saw-like toothed snout and above features, hence it is Pristis.