Conservation priorities refined

The researchers looked at evolutionary distinctiveness in combination with the criteria typically highlighted by the IUCN for a species to be included on its Red List: the species’ threat status, geographical range and life history traits. Their study found that mackerel sharks (Lamniformes), which are targeted largely by pelagic long-line fisheries, and guitarfishes, wedgefishes and sawfishes (Rhinopristiformes), which are kept as valuable by-catch, represent both high evolutionary distinctiveness and threat status. They are therefore key groups that need better protection.

The analysis highlighted 21 countries across the south-western Atlantic Ocean, West Africa, the south-western Indian Ocean and the north-western and south-western Pacific Ocean to prioritise for conservation action. Knowing which species are most threatened and represent the highest evolutionary distinctiveness, and where they are found, can narrow the focus for conservation strategies. The authors conclude that improved fisheries management, regulated trade and adequate spatial planning are required to mitigate the effects of overfishing, which is the single largest threat to the evolutionary history that sharks, rays and chimaeras represent.