A satellite tag is really just a data-collection instrument, and it's worth being specific about what that data actually is. Once attached to a whale shark, a tag records depth profiles, the surrounding ocean temperature, and the animal's long-distance movement over time — feeding the Galápagos Whale Shark Project a continuous picture of where a given shark goes and how it behaves at depth, long after it's out of sight of any boat.
Tagging isn't a one-off event, either. GWSP plans deployments across a research season, tagging multiple sharks rather than leaning on a single animal's data to represent the whole population, since individual whale sharks can behave quite differently from one another.
Tagging is also only one tool among several the project runs. Photo-identification — matching the unique spot pattern on each shark's flank, the same principle used to identify individual whales — builds a long-term catalogue independent of any tag. Blood sampling adds health data a tag alone can't capture. And starting in 2025, the project added ultrasound to its toolkit, opening up questions about reproduction and body condition that neither tagging nor photo-ID can answer by themselves.
All of it feeds the same downstream purpose: building a body of evidence detailed enough to make the case for expanding marine protected areas, rather than relying on anecdote or a handful of sightings to argue for it.
Source: adapted from Galápagos Shark Diving's own published article on its Galápagos Whale Shark Project partnership.