Abstract

Imagine you are standing on a boat. You look out, searching in all directions for a glimpse of a whale. But you can’t find any. Your excitement fades. Where are the whales? 

Many years ago, an ocean without whales was a real concern because we hunted them too much. Then we banned whaling and their populations grew. Yet some whale species are declining again. Why? 
To find out, we analyzed data from the feeding grounds of the North Atlantic Right whale. We found that warmer ocean temperatures made food harder to find. Without enough food, fewer whales were born. Also, whales started swimming north to find more food. This puts them in danger from getting hit by ships and tangled in fishing nets. So now they face a new threat from humans: climate change.