There has been some good news for environmentalists recently: a new study shows that the blue whale population is on the rise, and has made a complete comeback from the days when blue whales were almost decimated from whale hunting. Once on the verge of extinction, the California blue whale population has now almost rebounded to pre-hunting levels.
The study was published today, September 5, in the journal Marine Mammal Science. The study was led by Cole Monnahan, who is currently a doctoral student at UW.
Federal laws have not completely erased threats to the California blue whale -- for example, too many whales are still probably being hit by ships, but the whale population in California is thriving despite this.
Other populations of blue whales in America have not yet made leaps in population after hunting, but the fact that the California blue whale was able to make a return from the brink of extinction is hopeful for other endangered whale species out there.
Blue whales are extremely large, growing up to 100 feet long and weighing up to 190 tons. This is heavier than any other animal on Earth today, and heavier than any animal previously discovered on Earth. The Argentinosaurus, the largest dinosaur ever discovered, is only half the weight of an adult blue whale.
"The recovery of California blue whales from whaling demonstrates the ability of blue whale populations to rebuild under careful management and conservation measures," said Monnahan.
California blue whales are found in the Pacific Ocean, off of California's coastline and all the way to the Gulf of Alaska.
According to the new study, the current California blue whale population is around 2,200, which is about 97 percent of the estimated population before humans started hunting whales. The number 2,200 may not seem very high, but it is quite high in comparison to the number of California blue whales that were caught and killed from 1905 to 1971: 3,400. Based on those numbers, the scientists estimated that the California blue whale population was always somewhat low.
The estimates come from logs kept by Russian whalers. This data has only been available recently, as it was previously kept secret.
The researchers who authored the new paper on California whales said that the fact that the blue whale population is reaching historical levels may explain why the population's growth has been slowing down recently. A previous theory, that blue whales getting hit by ships was causing the population growth to slow down, doesn't explain the trend as well, the scientists said. Only about 11 blue whales are hit by ships along the American coastline a year. The data the scientists gathered suggested that even more whales could be hit by ships before the population dipped.
"Even accepting our results that the current level of ship strikes is not going to cause overall population declines, there is still going to be ongoing concern that we don't want these whales killed by ships," Branch said.
