The largest animals on Earth, blue whales can reach almost 100 feet long and weigh up to 190 tons. Northern Pacific blue whales were targeted by whalers between 1905 and 1971, reducing their numbers by approximately 3,400. The species has been listed as endangered since 1970.
In a report published Friday in the journal Marine Mammal Science, the authors state that the population of California blue whales has recovered to about 97 percent of their pre-whaling numbers.
“If you can whale them pretty extensively for 50-70 years and they are able to recover I think that says a lot about moving forward,” says Cole Monnahan, the report’s lead author. “In terms of things like climate change, it is hard to predict but I don’t think we would expect a precipitous drop off.”
Researchers note that the biggest threat to the massive cetaceans is no longer whalers but ships. As more ships traverse the busy California coastline, whale shipstrikes become more common.
This has led Santa Barbara authorities and conservation foundations to create an incentive program for cargo ships that agree to slow down as they pass through the narrow corridor formed by the Channel Islands and the west coast. It is a popular feeding ground for whales, which increases their risk of being struck. So far, six international shipping companies have agreed to participate in the pilot program.
Such progressive conservation policies have become a hallmark of California, according to CSULB Professor Chris Lowe. By comparison, blue whale populations in other parts of the world have not shown such healthy recovery.
“California blue whales are recovering because we took actions to stop catches and start monitoring,” says Monnahan. “If we hadn’t, the population might have been pushed to near extinction – an unfortunate fate suffered by other blue whale populations.”
Until 1966, Antarctic blue whales were hunted nearly to extinction. Estimates place their population at 1 percent of their original numbers.