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Changing the Way We Track the Ocean’s Giants
Dr. Alex Zerbini
For 25 years, Dr. Alexandre Zerbini has used the Argos system to track the ocean’s giants, and along the way, he had to reinvent the very tags that made it possible.
How a Childhood Encounter Inspired a Marine Biologist
In the sheltered bays of Península Valdés, on the Atlantic coast of Argentina, a southern right whale rolls at the water’s surface, venting a plume of mist into the cold air. The giant is visible for just a moment. Then, slipping under the water, the whale disappears, bound for a mysterious network of feeding grounds. For generations of conservationists, this is where the story ends, a whale seen, then swallowed by the sea. For Alex Zerbini, this is where his work begins.
Following whales beyond the horizon and returning with a record of their behavior once they dive out of sight, has led him to nearly every ocean. His drive to follow the mysterious animals across the planet was inspired decades earlier, on another beach. A young Alexandre, walking along a strip of sand in Brazil, would encounter a dolphin, igniting a life-long passion that has changed the way we track whales.
At just nine years old, walking along the beach with his father and brother, Zerbini came across a dolphin, tangled in a fisher’s net. He approached the fisher and asked what he intended to do with the trapped animal. The fisher bluntly explained to young Zerbini that he intended to cut up the dolphin and feed it to his dogs. Zerbini recalls something clicking in his mind and a sense of curiosity blooming. “I need to understand more,” he remembers thinking. “I need to know more.” His parents insist that Alex’s interest in becoming a marine biologist started as early as 3 or 4 years of age, and he hasn’t stopped talking about it since.
Tracking Whales Across the World’s Oceans
Today Zerbini is one of the world’s leading authorities on tracking large whales by satellite, with appointments at the University of Washington’s Cooperative Institute for Climate, Ocean, and Ecosystem Studies, NOAA’s Marine Mammal Laboratory, MarEcoTel, and Insitituto Aqualie. He has worked with the Argos system for about 25 years, spending much of that time chasing a deceptively simple question: what do whales do when no one is watching, and once we know, how do we keep them safe?
He works from no single lab, and there is no specific field season. Zebrini works with teams scattered across the globe, and his own calendar reads like a migration route. During 2026, he ran a project in Argentina in May, collaborated with Rutgers University tagging humpback and fin whales off New Jersey, joined a research cruise for killer whales in the Gulf of Alaska, managed a major right whale campaign in Argentina in September, and continued ongoing work in South Africa with the University of Pretoria. “I’m all over the world tagging and collaborating with people,” he said.
Why Satellite Tracking is Essential for Whale Conservation
Zerbini’s restlessness serves a larger purpose. Each of his projects attempt to provide answers to the mysteries lying in the depths of our oceans. As he explores the earth’s seas, he asks why satellite tracking is an essential component in whale conservation, finding real-world studies to ensuring our future.
Tracking Orcas Across the Ocean
For example, in Alaska, there are three “ecotypes” of killer whale; one that hunts marine mammals, one that eats fish, and one so elusive, scientists simply call it “offshore.” These diverse orca ecotypes behave so differently, that telling them apart and predicting their movements plays a major role in ensuring their safety. For instance, the fish-eaters tangle with trawl fisheries and are sometimes caught in their nets and killed, so mapping their core habitat lets Zerbini warn the industry where the risk of cross traffic with orcas runs highest.
Dually, because this work to map orca habitat is funded by the U.S. Navy, the tags also answer a question the organization is obliged to address in its environmental impact assessments: of the killer whales Naval exercises may affect, what share of impact belongs to each ecotype, and where. The Navy already knows roughly how many killer whales are out there; what it lacks is the specific percentages of each type of orca populate which regions. Through his research, Zerbini provides data, highlighting that the mammal-eaters favor one sea for a stretch of time while the fish-eaters work another. This is the kind of detail necessary for improved Naval planning.
Right Whales and Trade Routes
In Argentina, right whales serve as a test group for a new generation of miniaturized tags, and as a window on how a warming ocean reshapes migration and habitat utilization. Across the Atlantic, in South Africa, conflict in the Middle East has pushed shipping traffic down the continent’s coast, increasing the risk of collisions and endangering the whales in the region. Zerbini’s collaborators are working to determine whether a small nudge to a shipping lane could spare a whale’s life and improve safety.
But the through-line of Zerbini’s career is not any one species. It is the instrument itself, and a discovery that forced him to become an inventor.
Reinventing Whale Tags for Better Science and Animal Welfare
Early in his research, Zebrini and his colleagues were losing tracking tags at an alarming rate. In some cases, they saw a 40 percent failure rate, and it wasn’t the electronics. The problem was the way in which the tag was attached. Most whale tags must be deployed from a distance and anchored beneath the skin. Previously, no one had questioned whether this process was hurting the animals. As Zerbini puts it, rather plainly, the earlier mindset disregarded whether there was discomfort at the tag site. “If something bad is happening, they’re [the whale] going to stop us from doing this,” he said.
Zerbini understood the challenge and wanted to try a different approach. Collaborating with scientists who closely study humpback whales in the Gulf of Maine, they inspected deployed tags, and what they found was cause for concern. Some of the tags were fracturing inside the whales’ bodies, the transmitter shearing off while the anchor remained. Some of the animals experienced severe swelling at the implantation site and increased irritation.
So, they fixed them. The redesigned tags were more durable; they stayed on longer and swelling and irritation stopped. The tagged animals were measurably healthier. The benefit was scientific as well as ethical. “If the tags are affecting the natural behavior of the animals,” he explains, “then the data no longer represent the population, and conservation advice built on skewed data can be wrong.”
Zerbini’s rule for anyone entering the field is both a research standard and a creed, “Choose the right tag, test it, use a large enough sample, and treat the animals carefully and with love.”
How Argos Improved Whale Tracking
The tags themselves are, in a sense, sacrificial. They act like a piercing, Zerbini says. The body slowly rejects the tag, and it falls off. Long-term tags are never recovered. Therefore, everything depends on what the animal transmits before the tag is lost, which is why the recent overhaul of the Argos system provided a boost to his work, like an electric current igniting new opportunities. The arrival of the Kinéis nanosatellite constellation has been, in his words, “a massive improvement in data quantity and data quality.” His one note on the system: that the new pipeline was as automated as the old one. However, he sees this as an expected growing pain of a system still settling.
The Goniometer – Tag Retrieval Made Possible
Not all of the tracking happens from orbit, though. In the field, Zerbini leans on a goniometer, a highly sensitive handheld direction finder that listens for a tag’s own Argos signal and points toward it, giving a bearing and a rough distance from as far as several kilometers off in good conditions.
The goniometer is how his teams relocate a tagged whale on the water weeks to months after deployment. Tracking the tag using the device allows them to get close enough to photograph the animal and judge its body condition. This is the follow-up that tells them whether a tag is doing harm. And for the shorter-term tags that are meant to be retrieved, the goniometer is often paired with radio telemetry. This is how they home in on a small transmitter bobbing somewhere on the sea and recover it, along with the data stored inside, before the currents carry it out of reach.
As Zerbini tells newcomers, the more ways you have to find an instrument (the Argos satellites, radio, the goniometer), the better your odds of getting it back.
Gratitude from the Field, a Challenge for the Future
Asked what else he wanted the people behind Argos to hear, Zerbini offered thanks and a challenge. He and his fellow users deeply appreciate the leap the new satellites represent, and he urged Argos, CLS, and Woods Hole Group to keep pushing. He insists the technology helps the animals, and it reaches far beyond them into countless human uses.
Then he turned to his interviewers with an invitation of his own: come out in the field with us. His projects always have room, he told them, and next year’s field work would be a great opportunity for a visit, a few days on the water is enough to see how a whale is actually tagged. It is the same reason he has long brought tag engineers along: an afternoon beside a whale tends to change how a person designs and deploys the thing that goes on it.
Which in the end, is the same instinct that stopped a nine-year-old on a Brazilian beach; to go closer, and to know more.
This spotlight is drawn from Dr. Zerbini’s July 2026 interview with the Argos team. Spoken quotes have been lightly edited for clarity without altering their meaning. Biographical and technical background (institutional roles; details of the Kinéis constellation) verified against public sources including CICOES/University of Washington, NOAA, CLS/Argos, and Wildlife Computers.
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