Conservation biology
The strange-looking sawfish, itself a predator, falls prey to overfishing and habitat destruction.
The long-snouted, shark-like predators called sawfish have vanished from nearly 60% of their historical habitat and are nearing extinction, according to a mathematical method of counting marine species.
Sawfish (family Pristidae) are rays that live near seashores and in mangrove areas: habitats that are rapidly disappearing. To study what this means for the five species in the family, Helen Yan at Simon Fraser University in Burnaby, Canada, and her colleagues reviewed sawfish research conducted between 2014 and 2019 in 64 countries. From this, they estimated the distribution patterns of these fishes, which are known for their large size — some species routinely reach 5 metres in length — and their chainsaw-like noses.
The team found the creatures’ distribution patterns had changed in places affected by fishing pressures and habitat loss. These pressures have driven the fishes to extinction in 55 of the 90 countries whose waters they once occupied.
Saving the sawfish, the researchers say, will require countries to protect the creatures’ offshore habitats and to ban fishers from keeping sawfish that are caught in their nets.