A fisherman prepares to cast his line standing in the surf as a full moon rises at Mollymook Beach, located south of Sydney, Australia, February 23, 2016. REUTERS/David Gray

TORONTO (Thomson Reuters Foundation) - Climate change is pushing fish toward the planet’s North and South poles, robbing traditionally poorer countries closer to the Equator of crucial natural resources, U.S. biologists said in a study published on Wednesday.

Key species of fish are migrating away from temperate zones and toward the poles as global temperatures rise, according to a research team from Rutgers University, Princeton University, Yale University and Arizona State University.

The migration patterns of fish, a critical food source for millions of people, are likely to exacerbate inequality between the world’s poor and rich, they said.

The world’s wealthier areas tend to be in cooler regions closer to the poles.

“Natural resources like fish are being pushed around by climate change, and that changes who gets access to them,” said Malin Pinsky, one of the study’s authors and a marine biologist, in a statement.

The study, published on Wednesday in the journal “Nature Climate Change,” used data on fish migration patterns along with a mathematical formula that tracked the movement of natural resources and shifts in wealth.