Sawfish have disappeared from half of the world’s coastal waters and the distinctive shark-like rays face complete extinction due to overfishing, according to a new study by Simon Fraser University researchers, published in Science Advances.

Sawfish, named after their unique long, narrow noses lined by teeth, called rostra, that resemble a sawblade, were once found along the coastlines of 90 countries but they are now among the world’s most threatened family of marine fishes, presumed extinct from 46 of those nations. There are 18 countries where at least one species of sawfish is missing, and 28 more where two species have disappeared.

According to SFU researchers Helen Yan and Nick Dulvy, three of the five species of sawfish are critically endangered, according to the International Union for Conservation of Nature (IUCN) Red List of Threatened Species, and the other two are endangered.

Their teeth on their rostra are easily caught in fishing nets. Sawfish fins are among the most valuable in the global shark fin trade and rostra are also sold for novelty, medicine and as spurs for cockfighting.

Read more at Simon Fraser University

Image: Largetooth sawfish Pristis pristis in an aquarium. (Credit: Contributed/David Wackenfelt)