In the mid-1980s, Kathy Heise found herself tending a lighthouse overlooking a foggy channel in the Pacific Northwest. It became the perfect place to learn about killer whales, calling and echolocating along the Inside Passage of Vancouver Island, British Columbia. These were the early days of echolocation research. Heise and her husband — both budding marine biologists — were hoping to answer blue-sky questions about echolocation. How do killer whales use echolocation? Does turbid water affect it? And how does echolocation differ between whale populations?
After they arrived, she and her husband attached an underwater microphone (called a “hydrophone”) to the shore of Chatham Point in Johnstone Strait, 18 metres beneath the water line. Then, they started eavesdropping round the clock on the clicks and chirps of passing whales and dolphins.
When some whale chatter came over the line, they hustled out of the house and down to the shore. If the weather was good — often a crapshoot in the Pacific Northwest — she climbed into a skiff and motored out to the action. The first priority was to photo-ID the whales and confirm which social group they belonged to. (The British Columbian coastline is home to two fish-eating resident whale groups and a third group of marine-mammal eating Bigg’s whales, formerly known as transients.)
“Echolocation is very directional,” Heise explains. “If the animal is facing you, you’ll hear it. If the animal is facing away, depending on the angle, you don’t hear it. That’s how you can tell if the whales are coming toward you.” She carried with her a World-War-2 navy hydrophone, mounted on a pole, which she turned in all directions, scanning the ocean for calls.
The transient whales, she observed, listened silently for their prey to make a noise. The hydrophone would be quiet, but from the boat she could often see prey (typically porpoises or seals) floating silently at the surface, keeping their splashing to a minimum. Sometimes they would hide up against the research boat. When the whales made a kill, the ocean would suddenly explode with the eerie sounds of transient whale vocalizations.
At the time, these were entirely new and novel observations; no researcher had documented a transient whale-kill before. At Chatham Point, Heise also witnessed the arrival of Pacific white-sided dolphins on the coastline. These dolphins used to live farther out at sea and researchers knew very little about them. When they moved inshore, it gave researchers like Heise the opportunity to study them up-close and in the wild.
However, Heise was up against the technical limitations of the time. Her World War 2 hydrophone, for instance, could record up to 25 kilohertz. (The human ear hears sound frequencies up to 20 kilohertz.) We know now that whale echolocation extends to over 100 kilohertz, particularly when they zero in on prey.
Thirty years later, the technology has advanced hugely and Kathy Heise’s work on echolocation continues apace. In a recent study, she attached suction-cup eye-coverings to Pacific white-sided dolphins and observed how they used echolocation in a controlled habitat. The dolphin’s echolocation ability is impressive, but they don’t always use it reliably. According to the World Wildlife Federation, 300,000 dolphins, whales and porpoises entangle themselves in fishing nets and drown each year. Knowing more about how they become entangled could lead to improved fishing gear and save lives.
In the coming years, Kathy Heise’s work on echolocation will continue to expand in new directions. She advises non-profits, the shipping industry and local ports on guidelines that reduce underwater noise. Chatham Point is still a special place for her, where she had her first encounters with echolocation and saw how instrumental it was in the lives of whales and porpoises. Now she’s putting that knowledge to work, keeping the peace for underwater animals.