The Vietnamese often refer to the Pristis perotteti as “swordfish” or “sawfish”; while Westerners call it “sawfish.” Pristis perotteti has a long, saw-like snout with jagged teeth. The teeth on the saw are not real teeth but rather dermal denticles; once they break off, they do not grow back.
This species is abundant in the tropical waters of the Atlantic and Indian Oceans, as well as in some rivers and large lakes that connect to the sea. They can thrive in saltwater, freshwater, and brackish water. Despite their unusual and fearsome appearance due to their “saw,” Pristis perotteti is actually a type of ray.
The sawfish preys on crabs, shrimp, and various types of benthic animals. Its saw is used to drive prey off the bottom of the water: it sweeps its saw along the bottom to flush out hiding prey.
Additionally, the sawfish catches prey by attacking schools of fish. When it charges into a dense school, the sawfish thrashes its saw wildly. Moments later, several unfortunate prey may be struck and rendered unconscious. After a bout of chaotic “swordplay”, the sawfish begins to swim slowly to collect its spoils.
The sawfish also employs its “sword techniques” for self-defense whenever threatened by an attacker. Its slashing strikes can inflict serious injuries on its adversaries.
Although sawfish only defend themselves when they feel threatened, there have been instances where they have attacked and injured the legs of swimmers. Fishermen often encounter them at river mouths; the saw may get caught in nets, and when trying to free them, the nets can tear, causing injuries to the fishermen’s hands.
The average length of Pristis perotteti is about 5.5 meters, but occasionally individuals can exceed 6.1 meters in length. They typically weigh around 320 kilograms.
The sawfish is ovoviviparous: The eggs hatch in the uterus, with the embryos continuing to develop without nutritional support from a placenta (the embryos are independent of the mother in terms of nutrition). The embryos are nourished by yolk (the yolk sac connects to the embryo via a yolk stalk). By the time the young fish are born, the entire yolk structure has been absorbed.
In each breeding cycle, the mother produces about 20 live young, each measuring approximately 0.5 to 0.8 meters. When the young fish are still in the mother’s womb, the teeth on the saw have not yet emerged; the dermal denticles develop only after birth. The size of the teeth on the saw of the young fish quickly reaches proportional symmetry after they are born. Young sawfish reach maturity at around 10 years of age.
The lifespan of Pristis perotteti can reach 30 years or more.