A HUNGRY whale is a quiet whale. A new first-of-its kind study found the marine mammals vocalised less after a marine heat wave decimated their prey, making whale songs a barometer of the effects of climate change on ocean ecosystems. 

The waters of the Monterey Bay National Marine Sanctuary off central California in the United States are rich feeding grounds for blue, fin and humpback whales that cruise the coast during their annual migrations. Whales sense their surroundings largely through sound and create complex vocalisations, or songs, when they’re searching for mates and food.