Humpback whales migrate to tropical waters with temperatures ranging from 22 to 28 degrees Celsius to mate and give birth, where ocean warming could now lead to a shift in their range. Using data from regional surveys and 20 years of observations in a tropical and subtropical breeding area off the coast of Ecuador, we show that while the whales prefer the tropical breeding area off Esmeraldas, whale sightings in the cooler subtropical breeding area increase under warmer (ENSO—El Niño) conditions. Our results suggest that under ENSO conditions, humpback whales may reach the limit of their temperature tolerance in the warm tropical waters around Esmeraldas, whereas under La Niña conditions, cooler areas such as Peru and Manabí are less suitable, prompting the whales to migrate further north.
YAQU PACHA has supported this work for many years, and now this article by Judith Denkinger has been published.
