Bones Reveal Right Whales Are Rare, But Not Due To Overhunting (Video)
Image via BBC via video screengrab
The Northern Atlantic right whale is one of the rarest in the ocean. It was thought that overhunting during the 16th and 17th centuries is the cause, with overzealous whalers cutting numbers down so far that they aren't able to recover. Today, there are only around 350 of the whales left, but a new study of an ancient right whale bone found among bones pulled from a 16th century Basque whaling galleon and those found on the shores of Quebec and Labrador near Basque whaling station sites shows that it wasn't overhunting, but a historically low number of species members and lack of genetic diversity that has kept the populations small.Bones from whales were found within a 16th century Basque whaling ship discovered in 1978. After being excavated, the BBC reports that Dr Moira Brown, now at the New England Aquarium in Boston realized that extracting DNA from the bones could reveal information about right whale populations over the last several hundred years.
Along with Dr Brenna McLeod, previously at Trent University in Peterborough, Ontario, Canada and several other colleagues, the researchers pulled DNA from 218 whale bones recovered from the whaling ship and the shores of Quebec and Labrador near old Basque whaling stations. Only one was from a North Atlantic right whale - the rest were from bowhead whales.
Looking at DNA from 27 different parts of the single right whale bone, the researchers found that there were few genetic variations in that 400-year-old bone compared to today's right whale. If a large portion of the species had been lost, there would have been a larger number of genetic variations.
"This would not have been expected if the population had lost a lot of variation as a result of a large reduction in population size due to whaling," says Dr McLeod. "There was absolutely no evidence of a right whale targeted hunt. Whaling did affect the species, by reducing the population size, but not nearly to the extent that was thought."
"Instead of numbering in the 12,000 to 15,000 as was previously assumed and suggested, we think that the population in the western north Atlantic was much smaller, perhaps numbering a few thousand," she said.
Instead of overhunting, the scientists think that perhaps historic climate changes are to blame, such as glaciation events that could have forced the whales to change habitats and therefore food sources and calving grounds.
The North Atlantic right whale is still at dangerously low populations - and ship strikes, run-ins with nets, pollution and other factors are not helping the species to maintain its numbers - but here is one unusual case where whaling doesn't seem to be the culprit for its rarity.
A little more about the North Atlantic right whale:
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