Below the surface of the oceans, The majestic songs of whales fluctuates To the rhythm of the waves of repeated marine heat. This is revealed by a study by Monterey Bay Aquarium Research Institute (Mbari), carried out between 2015 and 2021 in the North Pacific and New Zealand waters.
During these six years, a hydrophone placed at the bottom of the ocean allowed researchersAnalyze the vocalizations of several species of whales : blue whales, common rorqual and humpback whales. The objective? Better decode the rhythm of underwater life, detect imbalances and monitor the impact of human activity and climatic disruption on the behavior of marine species.
The disappearance of the Krill, an essential diet of the blue whale
Marine heat waves between 2015 and 2021 are caused almost disappearance of the Krillmain source of feeding blue whales. The latter, unlike other species studied, cannot vary their diet and depend on the krill to survive.
In 2013, a marine heat wave abnormally extended in the Pacific, from Alaska to Mexico, nicknamed “The Blob”, had a serious impact on the population of Krill. « The whole ecosystem is upset, and the Krill disappears. So the animals that depend on it are found without anything ”, explains Kelly Benoit-Bird, also a member of the Mbari study. This is the case with blue whales.
“It is only once the trendy hydrophone that I have achieved to what extent this world of sounds can help us to understand the human impact, nature, and the balance between the two,” says John Ryan, oceanograph researcher, member of the MBARI study.
While the latter evolve in an environment modified by climate change and the noise of maritime activity, Their voice is a vital indicator ocean health.
A decrease in whale song by 40%
With the scarcity of prey, the blue whales are constraints to spend more time looking for food. Consequence of this imbalance? They seek to save and devote less time to singing. This is what explains a 40% drop in vocalization of these marine mammals.
As summarizes the oceanographer John Ryan, “If you look more closely, it comes back to Try to sing as you die of hunger. All their time was spent looking for food. »»
References of the article:
National Geographic, Blue whales are going eerily silent—and scientists say it’s a warning sign
Science and life, blue whales become strangely silent, and it is not a good sign according to researchers
Plos One, Audible changes in marine trophic ecology: Baleen whale song tracks foraging conditions in the eastern North Pacific
