Sawfish have disappeared from half of the world’s coastal waters and the distinctive shark-like rays face full extinction because of overfishing, based on a brand new examine by Simon Fraser College researchers, revealed in Science Advances.
Sawfish, named after their distinctive lengthy, slender noses lined by enamel, known as rostra, that resemble a sawblade, had been as soon as discovered alongside the coastlines of 90 nations however they’re now among the many world’s most threatened household of marine fishes, presumed extinct from 46 of these nations. There are 18 nations the place a minimum of one species of sawfish is lacking, and 28 extra the place two species have disappeared.
In keeping with SFU researchers Helen Yan and Nick Dulvy, three of the 5 species of sawfish are critically endangered, based on the Worldwide Union for Conservation of Nature (IUCN) Crimson Record of Threatened Species, and the opposite two are endangered.
Their enamel on their rostra are simply caught in fishing nets. Sawfish fins are among the many Most worthy within the international shark fin commerce and rostra are additionally bought for novelty, drugs and as spurs for cockfighting.
The present presence of all sawfishes world-wide is unknown, however Dulvy warns full extinction is feasible if nothing is finished to curb overfishing and to guard threatened habitats, reminiscent of mangroves, the place sawfish can thrive.
“Via the plight of sawfish, we’re documenting the primary instances of a wide-ranging marine fish being pushed to native extinction by overfishing,” Dulvy says. “We have recognized for some time that the dramatic growth of fishing is the first menace to ocean biodiversity, however sturdy inhabitants evaluation is troublesome for low precedence fishes whose catches have been poorly monitored over time. With this examine, we deal with a basic problem for monitoring biodiversity change: discerning extreme inhabitants declines from native extinction.”
The examine recommends that worldwide conservation efforts give attention to eight nations (Cuba, Tanzania, Columbia, Madagascar, Panama, Brazil, Mexico and Sri Lanka) the place conservation efforts and satisfactory fishing protections may save the species. It additionally discovered Australia and america, the place satisfactory protections exist already and a few sawfish are nonetheless current, must be thought of as “lifeboat” nations.
“Whereas the scenario is dire, we hope to offset the dangerous information by highlighting our knowledgeable identification of those precedence nations with hope for saving sawfish of their waters,” says Yan. “We additionally underscore our discovering that it is truly nonetheless attainable to revive sawfish to greater than 70 per cent of their historic vary, if we act now.”