Researchers recently discovered that blue whales are lowering the frequencies of their songs, year after year. No one knows why, but scientists speculate that it is linked to human-caused changes in whale populations or in the ocean itself.
Whale populations were hunted almost to extinction in the 19th century. Some scientists speculate that lower frequency singing allows individuals to communicate with the remaining whales that are few and far between. Other possibilities point to the whales adjusting their song to compensate for changes in their environment. For example, shipping traffic has increased ocean noise by 12 decibels since the 1950’s and the whales may need to sing ‘louder’ to communicate. In absence of ocean noise, blue whale songs can reach over 800 miles.
This study, led by researchers from Scripps Institution of Oceanography and a whale song monitoring company, Whale Acoustics, found this change occurred in populations in seven different oceans.
“It’s even more remarkable, given that the songs themselves differ in different oceans” said blue whale research expert, John Calombokidis. “There seem to be these distinct populations, yet they’re all showing this common shift.”
Read the full story: http://www.wired.com/wiredscience/2009/12/blue-whale-song-mystery/#more-14978
- Tara Duffy, Blue Ocean Institute Graduate Intern, Stony Brook University