March 4, 2009—A baby blue whale (shown with photographer) filmed off Costa Rica may be the first to have been photographed underwater and adds to evidence that a blue whale hot spot in the Pacific Ocean is a birthing ground for the endangered species.
During a January 2008 expedition to the "Dome"—a warm-water region that draws blue whales from hundreds of miles away—the researchers had begun to lose hope of finding a calf. Then two telltale spouts began erupting at the sea surface.
"Oh, tell me that one of them is a small blow, please," Bruce Mate, of the Marine Mammal Institute at Oregon State University, says in the documentary.
One of the spouts did turn out to be that of a calf, which approached the research boat—surprising the scientists, given blue whale mothers' protective reputations.
A photographer and videographer dived in and soon had the visual evidence needed to identify the whale as a baby blue.
Averaging 25 feet (7.6 meters) long at birth, blue whale babies nurse for about seven months until they double in size. Gaining about 200 pounds (90 kilograms) a day, they are the biggest babies ever known to have roamed the Earth.
Blue whales were heavily hunted until a worldwide ban in 1966. Today they are listed as endangered by the International Union for Conservation of Nature, meaning they face a very high risk of extinction in the wild.
By comparing new and old photos of blue whale spot patterns—which can be as distinct, in their way, as human fingerprints—expedition member John Calambokidis later identified the Dome mother as a summer resident of California's Channel Islands. The researchers speculate that mother and baby returned to the islands, rich with krill but fraught with danger from increasing shipping traffic.
The destinations of other whales at the Dome remain a mystery—unfortunately for conservationists looking to safeguard blue whale migration routes.
On a previous trip, researchers had found that more than 75 percent of the whales at the Dome were from the U.S. West Coast. But the recent expedition found only 25 percent.
"It caught us by surprise," Calambokidis told National Geographic News. A whale expert from the Cascadia Research Collective in Washington State, Calambokidis has received funding from National Geographic's Committee for Research and Exploration. (The National Geographic Society owns National Geographic News.)
The Dome's importance to the struggling species, though, is no mystery.
"We're quite confident now that this is one of the very, very important areas for blue whales in the entire world," Mate said.
Corrected March 5, 2009: The original version of this story stated that experts believe the calf in the video above may be the first live newborn blue whale caught on camera. Researchers cast doubt on that claim, and the story has been amended accordingly.
ON TV: Kingdom of the Blue Whale airs in the United States on the National Geographic Channel, Sunday, March 8, at 8 p.m. ET/PT.