Fin whales are the second largest animals on Earth, second only to blue whales. And like their slightly larger blue whale cousins, fin whales were hunted nearly to extinction during the whaling days. They’re still listed as endangered, though their numbers are recovering.
In order to know how well they’re doing, scientists need to map out the different populations of fin whales. In other words, they need to know which groups of fin whales tend to interbreed with each other and which groups stand apart. This will allow them to determine which populations are numerous and doing well and which are small and perhaps in need of extra protection.
Scientists often use genetic data to map out populations. But fin whales are distributed throughout the world’s oceans. To get DNA samples from everywhere would be hugely expensive. But perhaps there’s an easier solution.
Fin whales sing, and like humans, the sounds they make are different in different parts of the world. So NOAA biologists are identifying different groups based on their song type, and then testing some of them genetically to see if those groups comprise reproductively distinct populations. If they do, then scientists will be better able to protect fin whales just by listening to them.