Mysterious Pacific whale sound

WHOI scientists have tracked a lone whale with a distinctive 52-hertz frequency call every year over a 12-year span—and over thousands of kilometers—using the Navy's hydrophone network built to monitor submarines. (Illustration by Jayne Doucette, WHOI)

From Wildlife Extra:

The world’s loneliest and unidentified whale swims alone around the Pacific

Hertz 52 – The unknown whale

April 2013. In 1989, a team of Woods Hole Oceanographic Institution (WHOI) biologists first detected an unusual sound in the North Pacific Ocean. It had all the repetitive, low-frequency earmarks of a whale call, but at a unique frequency-52 Hertz-far higher than the normal 15-to-25-hertz range of blue or fin whales. They recorded it again in 1990 and 1991.

With the end of the Cold War, the U.S. Navy partially declassified its Sound Surveillance System (SOSUS), a hydrophone network built to monitor Soviet submarines. Using SOSUS, the WHOI team picked up the lone call of the same 52-hertz whale and have tracked it every year since, as it roamed widely through the North Pacific, from offshore California to the Aleutian Islands off Alaska.

Only call of its kind ever heard

“It is perhaps difficult to accept that if this was a whale, that there could have been only one of this kind in this large oceanic expanse, yet in spite of comprehensive, careful monitoring year-round, only one call with these characteristics has been found anywhere, and there has been only one source each season,” the scientists wrote in their study, published in Deep-Sea Research.

Malformed, deaf or a hybrid

The 52-hertz call may be due to a malformation, or the whale may be a hybrid of two species, the scientists speculated, but whatever the cause, it “has provided an unusual opportunity to document the seasonal activities of what we believe to be an individual whale.” The route the whale follows is unlike any known species, but could be described as half way between blue and fin whales.

It has also been suggested that the whale might be deaf. Dr. Kate Stafford, a researcher at the National Marine Mammal Laboratory in Seattle, said there were reasons to believe that the whale was healthy. “The fact that this individual has been capable of existing in that harsh environment for at least these 12 years indicates there is nothing wrong with it,” she said.

Of course, it sounds like a whale, but there is no proof of that. The animal, or whatever it is making the moise, has never been seen, and the time lag between when the calls are recorded and when the information is examined and released make it impossible, currently anyway, to go and find Hertz 52.

Every year 1992 – 2004, the WHOI team picked up the 52-hertz call sometime between August and December and monitored it until the whale swam out of range, always within a few weeks in January or early February. Traveling 31 to 69 kilometres per day, it was tracked over a low of 708 kilometres one season and a high of 11,062 kilometres in 2002-03.

“The usual tracking for an individual whales last hours at best,” the scientists said.

The research was conducted by Mary Ann Daher, Joseph George, David Rodriquez, and William Watkins, who pioneered the field of marine mammal acoustics with William Schevill at WHOI in the 1950s, and who died in September.

Update June 2015: here.

2 thoughts on “Mysterious Pacific whale sound

  1. Pingback: Rare Omura’s whales studied in Madagascar | Dear Kitty. Some blog

  2. Pingback: North Atlantic right whales’ voices, new research | Dear Kitty. Some blog

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