Researchers at the Woods Hole Oceanographic Institute in Massachusetts have uncovered the oldest known recording of whale songs, captured off the coast of Bermuda.

Peter Tyak, a marine bioacoustician and emeritus research scholar at the institute, told Discover Wildlife that the recording was made on March 7, 1949, but researchers who captured the sounds did not catalogue it at the time because they did not know what it was.

Mr Tyak said: “WHOI archivists came across this last fall while digitising audio from a primitive underwater recording device and they immediately knew how significant it was.”

Whale songs were first documented by Bermudian Frank Watlington, who was working with the US Navy in the 1950s to develop underwater microphones intended to locate Russian submarines.

While Mr Watlington could not initially identify the noise, he played the recording to fishermen who were able to identify the sound of whales singing.

That recording, Solo Whale, was later included in a record of whale songs, and was added as an insert in National Geographic Magazine.

The newly uncovered 1949 recording was made as researchers were working with the US Office of Naval Researchers on experiments including testing of sonar systems and measuring the volume of explosives.

It was recorded on an early experimental underwater recorder known as the WHOI 'suitcase' and then etched onto plastic discs using an office dictation machine.

Laela Sayigh, a senior research specialist at WHOI, said earlier recordings are of great interest to scientists as they capture a time when the oceans were quieter and whales had to compete with less noise to be heard.

She added: “Data from this time period simply don’t exist in most cases.

“The ocean is much louder now, with increases in both number and types of sound sources.

“This recording can provide insight into how humpback whale sounds have changed over time, as well as serving as a baseline for measuring how human activity shapes the ocean soundscape.”