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Scientists have discovered a brand new to science call that humpback whales make. This previously unheard and unrecorded “impulsive sound” has been dubbed the “gunshot” by the research team.
Reported in the journal JASA Express Letters, the new call was recorded in November 2019, during the summer in the South Atlantic Ocean in a region called the Vema Seamount. Over 11 days, the moored hydrophones (a mike designed to go underwater) recorded over 600 calls that were not whale songs. Most of those calls were so-called “whups”, which are low and frequency modulated. But occasionally they picked up these previously unknown “gunshots.” Both types of calls were mostly recorded at night and in particular over a period of three days.
“We still don’t fully understand what the ‘gunshot call’ means, and it is fantastic to record it in humpback whales for the first time, it really shows how much we still have to learn about these incredible animals," Dr Kirsten Thompson, of the University of Exeter and Greenpeace International Research Laboratories, one of the scientists who led the project, said in a statement.
Researchers have linked the “whup” as a way for mother-calf pairs to remain in close contact. The sound helps them locate one another. The “whup” is also heard when humpback whales feed.
"Our study confirms that the whales passing Vema during their long journey across the oceans are feeding," Dr Thompson added. "Seamounts can provide rich habitat for all sorts of migratory species and we urgently need widespread protection of the global oceans to ensure these habitats can persist.”
Research such as this show that the high seas (Vema is 1,000 kilometers from South Africa) are rich in life and are worth protecting. When this location was discovered in 1959 it became quickly overfished. The area is now partially closed to fishing but there is no internationally binding treaties that protect these areas of the ocean.
“Fifty years ago, governments came together to turn around the fate of humpback whales and seeing many populations thrive gives us a glimpse of their lives in the high seas. Only 3% of the global oceans are properly protected and that’s nowhere near good enough to safeguard habitats that whales rely on,” Dr Thompson said.
The research was part of a scientific expedition conducted by Greenpeace International under the leadership of the Universities of Stellenbosch (South Africa) and Exeter (UK). In the 1960s the global population of humpback whales was around 5,000 but it has now recovered to more than 135,000 individuals.
