Study Shines Light on Noise and Whale Songs

For decades, humans have been enchanted with the songs of the humpback whale. First recorded in the 1960s, these songs have long captured our imagination and were even central to mobilizing support for the ‘Save the Whales’ Movement throughout the ‘60s and ‘70s.

Despite our fascination with humpback’s and their songs, however, there remain many unanswered questions as to why these whales are so musically inclined.

New research from scientists at Woods Hole Oceanographic Institute has provided some fresh insight into the world of whale songs. In a paper published this month in the journal Biology Letters, Aran Mooney and his team researched two components of whale songs: sound waves and particle velocity.

Unlike sound waves (the force that vibrates your ear drums), particle velocity (the physical vibration of a substance as sound moves through it) has yet to be studied thoroughly and is not fully understood. While researching off the coast of Maui, Mooney’s team discovered that particle velocity produced by whale songs—originally thought to travel a few meters at most—might travel much farther than originally thought.

Mooney found that they could measure vibrations from 200 meters away, but suspects that they could be felt as far as one kilometer away.

Humpback Whales Live in an Ocean of Increasing Noise

Previous research has shown that humpback whales could be potentially sensitive to particle vibrations in the water column. Unlike many marine mammals, humpbacks’ ear bones are fused to their skulls, which could allow for their jaws to act as giant, mammalian tuning forks, picking up particle velocity produced by other humpbacks, and potentially humans.

The humpback whale’s hearing evolved over millions of years in an ocean environment wholly different from the one we are now witnessing.

Today, a host of altogether new and alien sounds ring throughout the ocean. Offshore oil and gas explorations use literally earth-shaking blasts fired from airguns dragged along the surface. The blasts are powerful enough to penetrate the planet’s crust and bounce back to the surface, releasing the signatures of pockets of hydrocarbons from deep within the rock.

You need not be exploring for oil and gas to be adding to the sonic landscape of the oceans, however. According to Jesse Ausubel, the director of the Human Environment program at the Rockefeller University, “A cargo ship is basically a large rock concert passing by.”

And humpback whales don’t seem to show any affinity for this human-made noise. There is evidence to suggest that humpbacks respond negatively to anthropogenic sound, often ending their songs or even changing their songs’ frequencies in order to be heard over the unending and ever-increasing industrial drone.

With new shipping, mining, and construction ventures happening all the time, and ocean noise doubling every two decades, Mooney and his team’s findings could spell more problems for humpback whales. Most human-made noise in the ocean is low frequency, which contributes to low frequency particle motion. From Mooney’s research, it seems humpbacks could be especially sensitive to this noise. While we humans may not be able to hear well underwater, these sounds could come as relevant communication signals for humpbacks and other marine mammals.

A Call for Ocean Planning

Looking forward, a growing understanding of humpbacks, their songs, and their hearing capacity will continue to inform how we interact with these mammals, but also how we should protect them.

Though Mooney’s study took place off the coast of Maui, it has many implications for our dealings with humpback whales here in New England. Every year, humpbacks migrate mammoth distances, passing through our coastal waters in the spring and fall months, as they move between their tropical breeding grounds and their polar feeding grounds.

For us to be informed and prepared enough to accommodate these whales, it will be essential to look toward ocean planning and its potential for informing our relationship to the ocean. One component of the Northeast Ocean Plan is its data portal, which will include data and findings about marine mammals that’s accessible to everyone, and will be especially key for those in decision-making roles.

In New England, ocean planning continues to be of utmost importance and we hope decision makers will continue to rely on it in order to protect humpbacks and other marine animals traveling along our shores. The recent submission of the Northeast Ocean Plan marked a serious step forward in how we relate to our ocean resources and it will certainly prove invaluable as we look to protect our neighborhood humpbacks.