Humpback whales migrate to tropical waters with temperatures of 22 to 28 degrees Celsius to mate and give birth, where ocean warming may now be causing a shift in their range. Using data from regional surveys and 20-year observations in a tropical and subtropical breeding area off the coast of Ecuador, we show that although cetaceans prefer the tropical breeding area off Esmeraldas, cetacean sightings in the cooler subtropical breeding area are increasing 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, while under La Niña conditions, cooler areas such as Peru and Manabí are less suitable and whales move further north.
YAQU PACHA has supported this work for many years and now this article has been published by Judith Denkinger.