The fishermen of Iceland became concerned around a decade ago. The capelin, a small fish that’s a staple catch, and a crucial link in the ocean ecosystem, stopped migrating like they used to. To whom did they turn? A team of mathematicians.
“So what I think about is particles but each particle gets to make decisions. And it makes decisions based on what the particles around it are doing," Dr. Alethea Barbaro said. Barbaro is a mathematician at Case Western Reserve University.
"So I think about where a particle is, where it wants to go, then I move it there by multiplying it by some time step." She models the behavior of social organisms using an interacting particle model, where each particle represents one, or a group of, organisms. Her group found this works really well for predicting the movements of the capelin.
“It's really, it's a dance between the math and the science. We actually were able to take out the homing instinct and recreate the migration without the homing instinct. They actually were not sure whether or not the capelin have a homing instinct. But, what our model showed is that it's possible to get these migration routes without a homing instinct. And what that means - sadly, for the fisheries - is that it's less likely that the capelin would always go where they've historically gone, and, we were able to predict the 2008 migration.”
