Seabirds and humpback whales give early warning to marine heatwaves

Between 2014 and 2016, an extreme marine heatwave struck the North Pacific Ocean, affecting nearshore and pelagic (offshore, open ocean) ecosystems from southern California to Alaska. This unprecedented event, characterized by unusually warm ocean temperatures over a large area, was the longest-duration marine heatwave recorded to date. The Gulf of Alaska endured some of the most severe consequences of this heatwave, now known as the Pacific Marine Heatwave or “the Blob” (Fig. 1). Marine heatwaves, like the Blob, are increasing in frequency and intensity over time, and they can cause large-scale disruptions to marine ecosystems. The increased occurrence of these events across the world's oceans in recent decades necessitates an understanding of their impact on biological communities.