Whale watching is a popular pastime for tourists in coastal regions around the world. But marine biologists take cetacean surveillance to the next level. By attaching video cameras and electronic tags to these marine mammals, scientists are answering longstanding questions about how whales travel, feed, and live in the world’s oceans.
These details are critical to finding out how these species behave and to supporting conservation efforts where protective measures are required. But until recently, observing the ocean’s largest inhabitants was no easy task. Only in the past two decades have ever-more sophisticated tags and software allowed researchers to gather thorough data about whale behavior.
“What drives our research is a curiosity to understand how these enigmatic, gigantic animals live and operate,” says Jeremy Goldbogen of Stanford University. “For a lot of these big whales, how do they survive in an increasingly urbanized ocean, where they’re dealing with ships and fishing gear? We’re trying to understand basic information about their behavior, and that’s what these tags provide us with.”
Marine animal tagging began in the 1960s, with components that included kitchen timers. Now, a typical monitor includes the same gear as a basic cell phone, with tools like a clock, accelerometer, magnetometer, and audio-video recording equipment. Once attached, the kit stays on for about 24 hours and records how fast and deep a whale is diving, how it moves through space, and even the sound of water rushing past an animal on the move. “I call it digital natural history,” says Goldbogen. “We have a digital record, with video and 3D movement, of what a whale does on a daily basis.”
Ari Friedlaender of University of California, Santa Cruz has tagged more than a dozen dolphin and whale species, including humpback whales, blue whales, and minke whales—near Cape Cod, off the coast of California, and in the frigid waters of Antarctica, respectively. He and his colleagues analyze depth data and audio recordings to understand how these massive animals—who subsist on great quantities of relatively tiny prey like krill—get their meals.
Audio recording, for example, lets researchers measure the flow noise around each animal as it moves through the water. When whales travel at a brisk pace, there’s a lot of flow noise, but when they slow down, that sound is dulled—not unlike the sound of wind rushing around your car while you’re on the freeway as compared to the relative silence when you’re idling at a stop sign. By tracking when the speed of a whale increases, and then suddenly and dramatically decreases, these researchers are able to map the “lunges” that rorqual whales like humpbacks use to gulp down huge mouthfuls of prey at a time.
Tags also let researchers eavesdrop on what whales hear in their ocean environments which, in places with a lot of ship traffic and human activity, is a lot of racket. “In the ocean, where sound is a primary mechanism for communication, that can be a really disruptive thing for social animals,” says Friedlaender.
And tags that stay on for 24-hour spans let researchers observe more behaviors than ever before. For example, when Friedlaender and colleagues tagged humpback whales in Stellwagen Bank National Marine Sanctuary off the coast of Massachusetts, they discovered the species had several ways of foraging on the seafloor—feeding behaviors that also put whales at risk of entanglements in bottom-set fishing gear.
In 2014, Friedlaender and team were working in Antarctica and tagged minke whales for the first time—yielding new data that showed the species has carved out a niche by hunting krill under sea ice where larger species like humpbacks can’t go. “Part of it is just sitting and watching, which is quite powerful,” says Goldbogen.
Find out more about how researchers are using whale tags in the exhibition Unseen Oceans, which opens on March 12.
A version of this story originally appeared in the Winter 2018 issue of Rotunda, the Member magazine.