Threatened species of Delphinapterus leucas

The beluga whales of the St Lawrence river are critically endangered. Fewer than 500 remain. Originally, they were the target of whalers; today, they are vulnerable from shipping disturbance including collisions, noise pollution, habitat degradation, and above all toxic contaminants. The beluga is so contaminated by DDT and PCBs that dead carcasses have to be disposed of as toxic waste.