"Scientists analyzed whale songs recorded in the marine sanctuary between 2015 and 2021"
"A hungry whale is a quiet whale. A new first-of-its kind study found the marine mammals vocalized 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 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 vocalizations, or songs, when they’re searching for mates and food.
Scientists at the Monterey Bay Aquarium Research Institute (MBARI) and their colleagues analyzed whale songs recorded by underwater microphones in the marine sanctuary between 2015 and 2021, a period that included a years-long marine heat wave that researchers have linked to climate change. It devastated populations of krill, anchovies and sardines that the cetaceans eat.
“The whales all exhibited the lowest levels of song when conditions were the worst,” but vocalized more when the heat relented, said John Ryan, an biological oceanographer at MBARI and the lead author of the peer-reviewed paper published last month in the journal PLOS One. “Because they experience these very strong changes in their ecosystem in ways that we can perceive, they are good ecosystem sentinels.”"
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