Whales are known to get around, sure, often migrating from warmer breeding grounds to colder waters where food is more abundant. But just how far can whales migrate? According to researchers from Oregon State University, the answer is “a lot:” Satellite tracking reveals that one endangered North Pacific gray whale named Varvara traveled from Russia’s Sakhalin Islands to Baja, Mexico and back – a round trip of nearly 14,000 miles.
The whale’s journey is so remarkable, in fact, that it has scientists doubting distinctions between whale species.
“The fact that endangered western gray whales have such a long range and interact with eastern gray whales was a surprise and leaves a lot of questions up in the air,” said Bruce Mate, director of the Marine Mammal Institute at Oregon State University and lead author on the study. “Past studies have indicated genetic differentiation between the species, but this suggests we may need to take a closer look.”
Eastern gray whales nearly went extinct due to the whaling industry, and their numbers plummeted enough to warrant placement on the endangered species list. Thanks to conservation efforts, their numbers grew enough for them to be delisted in 1996. Today they thrive, with an estimated population of about 18,000 members.
Western gray whales, thought to be an entirely different species, have a similar story. They were actually believed to be extinct until the 1970s, when a small group of about 150 animals was discovered near Russia off the Sakhalin Islands. That population has been closely monitored by both Russian and American marine biologists since the 1990s.
What has scientists questioning the genetic diversity is the fact that Varvara’s journey took her to three major breeding sites for eastern gray whales. The researchers now wonder whether the species are distinct at all. They may have been, at one time, but now it’s possible that what are believed to be western grays near Russia are really just a group of eastern grays expanding their range.
“The ability of the whales to navigate across open water over tremendously long distances is impressive and suggests that some western gray whales might actually be eastern grays,” Mate said. “But that doesn’t mean that there may not be some true western gray whales remaining. If so, then the number of true western gray whales is even smaller than we previously thought.”
Since learning just how far these whales are capable of traveling, scientists have compared photographs of whales taken in Russia with those taken in British Columbia and Mexico and found dozens of instances of whales making the trip. Conservation for western gray whales, if they still exist, proves difficult: Their habitats put them directly in contact with industrial fisheries, and their unknown migration routes make them difficult to track.