Whales and Dolphins
More than 350 scientists and conservationists from 40 countries have signed a letter calling for global action to protect whales, dolphins and porpoises from extinction.
They say more than half of all species are of conservation concern, with two on the "knife-edge" of extinction.
Lack of action over polluted and over-exploited seas means that many will be declared extinct within our lifetimes, the letter says.
Even large iconic whales are not safe.