Whales are big-arse animals. They’re so big, in fact, that satellite technology is now good enough to spot them from space.
It seems improbable, and yet new research shows satellites can not only spot whales, but help scientists distinguish between species. The findings have major implications for conservation, particularly in hard-to-reach locales (which is to say, basically the whole ocean).
Previous studies have provided a proof of concept for spotting whales from space, but the results have been mixed owing to the poorer resolution of older satellites. The new findings published this week in Marine Mammal Science under the delightfully-named study “Whales From Space,” rely on satellites launched by Digital Globe in 2014 that provide an eye-opening resolution of 30cm.
That offers a view that the researchers say is 1.6 times better than previous imagery, something that “is essential for identifying an object as a whale, and for differentiating species.”
Rather than scanning the whole ocean, the researchers with the British Antarctic Survey and University of Cambridge chose four locations known to be hotspots for either grey, fin, humpack, and southern right whales. Those locations include ocean off of Hawaii, Mexico, Argentina, and Italy, and the imagery they analysed was captured at times when no other whale species were likely to be present.
After blending colour and black and white imagery, researchers painstakingly scanned each image. Looking over a 100km² area took about three-and-a-half hours on average. They also conducted an automated analysis to gauge the reflectivity of individual images. Whales tend to be more reflective than dark ocean but less so than boats, planes, and other objects that can be snapped from space.
They then kept what they called “the purest ‘whale pixels’” for analysis, words that have likely never appeared in that order ever before.
The images with whales are astoundingly detailed. Far from being just little blobs, the whales’ tails and flippers are clearly visible, making it possible to identify specific species. Even the white patches on southern right whales’ head were clearly visible in some images. The images are serendipitous enough to capture whales breaching, swimming, and doing other whale things in the middle of the ocean.
This could be a big deal for conservation when it comes protecting endangered species like the blue whale, as well as unlocking the secrets of cetaceans in the high seas.
“This is really cool to expand capabilities with the imagery,” Michelle LaRue, an ecologist at the University of Minnesota who has used satellites to track seals (which look little grains of black rice) and was a reviewer of the study, told Gizmodo.
“I think whales in particular pose an extra level of complexity due to the need for calm sea state and their being at the surface, but my hope is this technology can add to other datasets from aerial and shipboard surveys.”
Unfortunately, the automated technique still had a tough time distinguishing between whales and the ocean so researchers are stuck eyeballing images for whales for now. Improving their whale-spotting algorithm could make it more useful in the future, especially as satellite imagery improves further. And crowdsourcing the hunt for whale pixels — something LaRue was able to do with her seal search — could help speed the process along.
Regardless, it’s still worth marvelling that we can see whales from freaking space.