
GOTLAND, SWEDEN—It’s a cold, dreary day in early March, and Josefin Sundin is standing in one of the two aquarium rooms at the Ar Research Station on a remote corner of Gotland, a Swedish island in the Baltic Sea. “This is where it all happened,” she says, while gazing around as if searching for fresh clues. Her colleague and friend Fredrik Jutfelt takes cellphone pictures.











