California blue whales have recovered from whaling, according to new research by the University of Washington. Researchers say this is the only population of blue whales to have rebounded from being hunted.

The California blue whales now number about 2,200, and while that number seems low, it represents about 97 percent of their past numbers. Their recovery is largely due to conservation efforts on the U.S. West Coast. Blue whales are the largest animals on earth, measuring nearly 100 feet in length and weighing 190 tons as adults. 

“The recovery of California blue whales from whaling demonstrates the ability of blue whale populations to rebuild under careful management and conservation measures,” says Cole Monnahan, lead author on the research submitted to Marine Mammal Science.

Though California blue whales are the only population of blue whales in the world known to have recovered from whaling, scientists are still making efforts to protect the species. Whaling is the hunting of whales primarily for meat and oil. 

“Our findings aren’t meant to deprive California blue whales of protections that they need going forward,” Monnahan said. "California blue whales are recovering because we took actions to stop catches and start monitoring. If we hadn’t, the population might have been pushed to near extinction – an unfortunate fate suffered by other blue whale populations. It’s a conservation success story.”