In a study published in the Proceedings of the National Academy of Sciences, the researchers overlaid maps of where each of the world’s 129 species of marine mammal species – about a quarter of which are currently facing extinction – is found, creating a composite map that revealed locations with the highest species richness.

‘This is the first time that the global distribution of marine mammal richness has been compiled and presented as a map,’ said co-authors Sandra Pompa and Gerardo Ceballos of the NAUM. ‘The most surprising and interesting result was that all of the species can be represented in only 20 critical conservation locations that cover at least ten per cent of the species’ geographic range.’ Nine of these locations – making up four per cent of the world’s ocean – had particularly high species richness, providing habitat for 108 marine mammal species in all.

Unfortunately, when the researchers looked at how pollution, local climate disruption and commercial shipping overlapped with the species richness in or near these nine key sites, they found evidence that they were particularly badly affected. ‘At least 70 per cent of the richness areas coincide with regions highly impacted by humans,’ said Pompa and Ceballos. ‘This is powerful information that obliges us to enhance marine conservation.’

October 2011