Blue whales sing less when they are hungry and more when they are plentiful, a recent study has revealed. Researchers have listened to whales off the coast of California for six years and found their songs increased following the ocean heat wave despite multiple press outlets claiming that blue whales remain silent.
Whales have a variety of vocalizations, but only men sing. There is evidence that men use songs to attract women and communicate with other men, John Ryan, the lead research author of the biological oceanographer at the Monterey Bay Aquarium Institute in California. “It’s a key part of how they feel about their world and interact with each other,” he told Live Science.
The song also offers researchers the opportunity to study whales. Sound travels very well into the water, making it more efficient in vast oceans than looking for animals looking for.
You might like it
“If we’re nearby and on the surface, we can see one of these whales. It’s on the surface, but we have to be very close,” Ryan said. “In contrast, if one of these whales is anywhere within the thousands of kilometers of area around our hydrophone, we hear them.”
In February, Ryan and his colleagues presented their research in the journal PLOS One, which used a hydrophone or underwater microphone, recording blue (Balaenoptera Musculus), Humptera (Megaptera novaeangliae), and Finale (Balaenoptera bysalus). The team then compared the acoustic data with National Oceanic and Atmospheric Administration (NOAA) fisheries data. Scientists have found that whales sing fluctuate based on food availability, and whales sing less when food resources are scarce.
The study began in 2015 at the peak of a catastrophic ocean heat wave known as “blobs.” This heat wave disrupts marine ecosystems and leaves whales starved. As a result, 2015 was the year in which researchers heard a year in which there were fewer whale songs. However, as temperatures cooled and the marine ecosystem slowly recovered, the whales found their voices again.
Related: The eerie “Biotwang” noise coming from the Mariana Trench was finally explained 10 years later
In July, National Geographic reported that the blue whale was silent. However, although the amount of whale songs in the study was different year by year, all three whale species were sung more at the end of the study period compared to the beginning. In other words, the whale was not silent at all. They were heard more frequently after the heat wave.
The Blue Whale song rose dramatically between 2015 and 2018, falling between 2018 and 2020, and again in 2021. Researchers believe that whales cannot put much energy on songs when food availability is low.
“In particular, with blue whales, they can’t switch prey, so they need to search farther and wider for the only prey they eat,” Ryan said. “If they have to devote more time and energy to foraging, then I can imagine that there will be less time and energy available for other actions.”
Chemical analysis of whale skin samples confirmed that blue whales continued to eat Krill when there were few available. In contrast, humpback whales switched between krill and fish (anchovies and sardines) depending on availability. As a result, research shows that it was the only whale species that had a continuous rise in singing over the course of six years.
“Whale food resources changed over the six-year study period, so we found that humpbacks are more resilient than blue whales,” Ryan said. “This is because humpback whales have a more flexible foraging strategy and are eating different types of prey,” he added.
The findings were consistent with a 2023 study published in the journal Ecology and Evolution, which found certain blue whales calling New Zealand during the summer of 2016 and 2018. Both studies highlight the negative effects of marine heat waves on whales.
Extreme ocean heat waves have tripled over the past 80 years, with even wider heat waves in 2023 and 2024. The latest Whale Song survey covers data collected by June 2021, so it is currently unclear what happened. But while climate change has made the world’s oceans warmer, whales off the coast of California have not “stop singing.”
Ryan said he has been collecting data since the end of the research period and is currently studying those numbers. When asked if the whales were silent since 2021, he replied: “No.”
Is the blue whales declining?
Blue whales are much more unusual than they did in the early 1900s before modern commercial whaling destroyed the population. Since then, NOAA says blue whale hunting has been banned and its population has grown. However, most population estimates are years ago.
The latest draft NOAA US Pacific Marine Mammal Stock Value says that there are approximately 1,898 blue whales in the population of the eastern North Pacific. However, the estimates are based on data collected in 2018. The global population is estimated to be between 5,000 and 15,000 adults, according to the IUCN Red List of Threatened Species, but that figure is also based on the 2018 rating.
Source link
