For ten years, marine biologists and Indonesian fishers worked together on the unlikeliest of partnerships — and it just paid off in a big way.
Scientists from Konservasi Indonesia and the Elasmobranch Institute Indonesia have published the results of a decade-long satellite tracking study of whale sharks (Rhincodon typus), the gentle, school-bus-sized filter feeders that drift through the Indo-Pacific. By tagging more than 70 individuals, the team produced one of the largest whale shark tracking datasets ever assembled — and the first detailed survey of its kind in the Indo-Pacific, where roughly 60% of the world's whale shark population swims.
The data revealed migration routes, feeding hotspots, and a previously unknown nursery where young whale sharks gather. Indonesian authorities are now using the findings to design a new marine protected area tailored to the species' actual movements rather than guesses on a map.
A fish story that starts with anchovies
The breakthrough came from an unusual source: bagan fishers, who work from floating wooden platforms across Papua, Sumbawa, and Sulawesi. At night, they shine lights into the water to attract shoals of anchovies. Where the anchovies go, the whale sharks follow — and over time, the world's biggest fish learned that the easiest meal in the sea was hovering directly under those platforms.
"The whale sharks are a good omen for the fishers," says Edy Setyawan, the study's lead conservation scientist. "They know when the whale sharks come, that means that lots of small fish or anchovies are around."
By 2010, that relationship had grown into something rare in the ocean: a stable, predictable meeting point between people and a giant, endangered animal. Marine biologist Mark Erdmann, who had been working in Indonesia since the 1990s, spotted the opportunity. Instead of chasing whale sharks across thousands of miles of open ocean, his team could simply meet them at the bagans, calmly fitting fin-mounted satellite tags capable of returning up to three years of data.
What the tags revealed
Starting in 2015, researchers tagged whale sharks at four key sites: Cenderawasih Bay, Kaimana in West Papua, Saleh Bay in Sumbawa, and the Gulf of Tomini in Sulawesi. The whale sharks were monitored for stress levels before, during, and after tagging — and the procedure proved safe enough to scale up.
What followed was a flood of data. The tags pinged satellites every time a shark surfaced, painting detailed maps of corridors that link feeding grounds across thousands of kilometers. Some animals stayed local. Others made long, looping journeys. And in one corner of the region, researchers identified a nursery area where young whale sharks repeatedly returned — a critical clue for protecting the species' future.
Whale sharks are slow-growing and reproduce late in life, which makes them especially vulnerable to fishing nets, boat strikes, and shrinking food supplies. Knowing where the youngest individuals gather is the kind of information that turns a vague conservation goal into a specific, defensible boundary on a map.
From data to a marine protected area
Indonesian agencies are now using the tracking data to draft the boundaries of a new marine protected area designed around real whale shark behavior. The results were published this month in the journal Frontiers in Marine Science.
The collaboration model is also drawing attention. Rather than excluding fishers, the study leaned on their daily knowledge of the sea — and benefited from a coexistence that has quietly evolved between bagan platforms and whale sharks over the past 15 years. If the new protected area can preserve both the sharks and the fishers' livelihoods, it could become a template for how conservation works in busy, biodiverse seas across Southeast Asia.
For now, more than 70 tagged giants are still cruising Indonesian waters, sending home the data points that will shape their own protection.
