Can Satellites Really Detect Whales From Space?

This article is from Hakai Magazine, an online publication about science and society in coastal ecosystems. Read more stories like this at hakaimagazine.com.

The pandemic forced all sorts of people to bring their jobs home with them. For Cortney Watt, an ecologist at Fisheries and Oceans Canada, that meant building six fake belugas in her garage. It was a strange project with an even stranger purpose: to see if she could see the whales from space.

Watt built the belugas from canvas and lumber and tested out a pulley system in a swimming pool to control the depths of the dummies. In experiments in various lakes, Watt tested how deep below the water’s surface a satellite could see her fake whales. She can apply those results to count real belugas in the Arctic. Surprisingly, current satellite imagery is clear enough that Watt can even see when one beluga dives below another. It’s an unexpectedly optimistic finding for the budding field of whales-from-space research.

The effort to track whales with satellites has seen a slow start. The first successful attempt was in 2002—decades after researchers first used satellites for land-based wildlife studies. But the appeal is obvious. Photographers can spot whales from a small plane, but that’s limited by how far the plane can travel. Underwater microphones can monitor whales, but only if they’re singing. A research boat might visit an Arctic fjord one time, but a satellite can take images all season.

“The benefit of having a satellite image is you can get a huge instantaneous image of an area,” says Watt.

Whales may be the largest creatures on Earth, but finding them with satellites has its problems. For instance, commercial satellite companies serve the highest bidders first—rarely whale researchers. And researchers can’t piggyback off existing photos because few other customers care much about the ocean beyond the coastline. Scroll a few kilometers off the coast on Google Maps and watch the resolution crumble.

Even if a whale does surface for a photo, a 12.5-meter North Atlantic right whale only appears as an 83-pixel smudge on the sharpest satellite images. Researchers can zoom in, but the whale will never be any clearer than a muddy amalgamation of 83 colored squares. And since one satellite photo can cover up to 200 square kilometers, it’s like taking a picture of a toothpick on the sidewalk from an upstairs balcony.

Another hurdle is the whales themselves. Belugas, Watt found, are easy to distinguish with their highly contrasted pale skin. In comparison, southern right whales are the same color as the water and much harder to spot, while humpbacks hide behind acrobatic splashes.

The lack of satellites is another obstacle to the field’s growth.

Currently, the best commercial satellite is the WorldView-3: “the Cadillac of satellites,” says Matus Hodul, a remote sensing researcher at Simon Fraser University in British Columbia. The WorldView-3 is the sharpest satellite available outside the military, and it can pick up whales’ individualized colors and patterns. Last year, Hodul used the satellite to identify the first specific whale from space, a North Atlantic right whale named Ruffian recognizable by his distinctive white scars.

The conditions for the photo were perfect: no clouds, no waves, and hundreds of whales softly skimming the surface of Cape Cod Bay in Massachusetts. In that one image, Hodul spotted 72 North Atlantic right whales out of a worldwide population of maybe 350. The species is one step from extinction, but incredibly, researchers still don’t know where half of the population goes each summer. Satellites could fix that.

Everyone, however, is fighting for time on the WorldView-3, Hodul says, and a single image can cost tens of thousands of dollars. But issues of coverage, cost, and clarity will change with time. One company is ready to launch a chain of six commercial satellites this year, while another is developing a satellite with resolution three times sharper than the WorldView-3.

While the engineers build more satellites, whale researchers still have plenty of work to do on Earth.

Right now, says Hodul, the best way to spot whales by satellite—whether the images were taken specifically for finding whales, or snapped for other reasons—is to have someone painstakingly go through each image. “You’re going to be looking at hours and hours of water with one or two whales interspersed,” he says.

An automatic whale finder would save everyone time, but there aren’t enough images to train an algorithm yet. “We need automation, but we need people to share their data,” says Hannah Cubaynes, a research associate at the British Antarctic Survey. Ideally, the growing number of researchers using satellites to search for whales could contribute their results to an open library, including key details like species, location, and satellite used. Programmers could then build an algorithm that passively pinpoints whales and helps researchers fill in the blanks on migration routes.

The conservation value is clear, says Cubaynes: to save the whales, researchers first need to know how many there are. “Ultimately,” Cubaynes says of satellite research, “it’s finding whales where we’ve never been before.”

Watt isn’t packing up the homemade belugas just yet. She still has plenty of research questions in the Arctic. So far, she’s only surveyed for belugas in the fjords where they congregate. What happens when the whales are in open water overlapping with other species? Can a satellite distinguish one mammal from the next? Maybe it’s time to build some fake narwhals and find out.

This article is from Hakai Magazine, an online publication about science and society in coastal ecosystems. Read more stories like this at hakaimagazine.com.

Related stories from Hakai Magazine:

• Giving Bambi the Boot
• In Norway, Whale Watchers Churn a "Soup of Chaos"