Drones can spot a whale wasting away

A photograph taken above a whale can reveal that it's wasting away. In research on endangered Southern Resident killer whales, animals in poor body condition were two to three times more likely to die in the following year than healthier animals. That turns an overhead photograph into something much more useful than a beautiful view: an early warning. Researchers can follow changes in individual whales and spot declining condition while the animal is still alive, creating an opportunity to respond before it deteriorates beyond recovery.

The technique is called photogrammetry, which means taking measurements from photographs. A photograph alone doesn't tell you an animal's actual size. Researchers need a scale, using the distance to the animal and the camera's focal length to translate the image into real measurements. With that information, they can estimate length, track growth and assess body condition. Photographs also help identify individual animals, so the measurements don't have to remain anonymous snapshots. They can become repeated observations of the same whale. Drones bring this established photographic technique above animals that researchers also study from boats, land and crewed aircraft.

Sometimes the warning is brutally visible. One Southern Resident female developed a narrowed outline around her head as she lost fat, leaving the shape of her skull more apparent. An aerial photograph recorded that emaciated condition just three months before her death. Across the study, researchers also found links between Chinook salmon abundance and body condition in some pods, although the pattern wasn't the same for every group. That's the conservation value of measuring living whales: the images can connect an animal's shrinking body with the food available to it, helping managers investigate where and when more accessible prey could matter most.

Other drones deliver equipment rather than just carry cameras. Researchers have used them to place temporary tags on whales' backs with suction cups. The conventional approach involves bringing a small boat alongside and reaching out with a long pole. A drone can approach from above instead, reducing the need for repeated close boat approaches. Once attached, a tag can record details such as depth, speed, orientation and acceleration; some also carry cameras and sound-recording equipment. These are intimate records of dives and activity, collected while the whale moves through the water. The attachment is temporary, typically lasting around a day for the tags described by Ocean Alliance.

The research boat hasn't vanished. It's farther away. In humpback research off Hawaiʻi, teams have deployed tags by drone while their vessel remained several hundred meters from the animals. The approach has also let them tag a skittish singing male they couldn't have reached with a pole. Those close-up movement records help researchers investigate energy expenditure and the biological consequences of disturbances such as vessel traffic. Paired with measurements of body condition, this kind of work gives conservation a more useful question than simply asking whether a whale is still there: how well is it living, and what's making that harder?