The grey whale population may not have recovered from the effects of hunting as well as previously thought, according to a study.
The research from Stanford and Washington universities in the US found today's grey whale population of almost 22,000 was well below the estimated recovery number of 96,000.
The report adds that large numbers of the whales have recently been discovered starving. This could be the result of a reduction in food supply in their Arctic feeding grounds because of climate change, say researchers.
The study raises questions about how many whales the oceans can now support and whether future numbers could be affected by over-fishing and climate change.