California blue whales have rebounded after dealing with commercial whaling for decades, according to new research from the University of Washington.
Research shows that their numbers are back to where they were before humans started hunting the species.
Cole Monnahan, who is getting his Ph.D. in quantitative ecology at the University of Washington, says he originally stumbled on blue whales as a focus for his thesis work, but it didn't take long for him to get hooked.
The research is published in the journal Marine Mammal Science.
"They are the largest animal that is alive today and that has ever lived, much larger than the largest dinosaurs," he said, according to BBC News. "For me, I think it's really cool. They're like this giant animal and yet we know actually relatively little about them. They're very difficult to study."
To find out why the blue whale population stopped growing over the past 20 years Monnahan used deep sea recordings of their calls to figure out how many California whales are around today.
He then plugged that figure into an equation along with other data, like the number of captured whales due to whaling in the past, and the number of ship strikes taking place.
Blue whales as a species are not doing well around the globe, Monnahan said. The California population of approximately 2,200 has recovered to 97 percent of their historical levels, according to BBC News.
Annual fatal ship strikes only have a minimal impact even when they occur in numbers above legal limits.
"We actually do estimate that they are back where they were before we started whaling. It's just there's a natural limitation on the population," he said.
The study shows that whales are back at a level that the ecosystem can naturally carry. Even so, Monnahan believes it is important that protections for the endangered species remain intact.
"California blue whales are recovering because we took actions to stop catches and start monitoring," said Monnahan. "If we hadn't, the population might have been pushed to near extinction - an unfortunate fate suffered by other blue whale populations."
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