Sea Sounds, Ship Strikes, and Cetacean Small Talk

Bookmark and Share

A shuddering start, followed by a calculated growl. A rattling hiss that speeds away. A wayward clicking, the uncanny insect. A 1950s sci-fi siren of something strange and otherworldly.

A deep, booming thud.

Again.

The dull drone of a tanker passing through the Massachusetts Bay, lasting hours.

These are sounds of the sea, and they are human-made sounds. A motorboat, a Navy sonar’s shriek, the knock of oil exploration. After digging through this “acoustic smog,” one might occasionally hear the low whoop of a right whale’s up-call.

Southern Right Whale

This cetacean small-talk is one of many of the right whale’s calls—others hold names like a set of horror film sound effects: the gunshot (perhaps through a silencer), the scream (more like a very large whining dog), and the moan (which sounds like, well, a moan). But the up-call is the one being picked up by buoys in the Massachusetts Bay, in an effort to reduce ship strikes.

The most recent estimate of their population reported by NOAA is 444. This is higher than IUCN’s 2008 estimate of 300-350, of which far less than 250 were adults capable of reproducing.

Sorting through sounds is no easy task, especially with all the activity that goes on in the bay. After the software in the buoys collects and sorts the sounds that might come from right whales (short sounds in a low range), it sends them back to the Right Whale Listening Network at the Cornell Lab of Ornithology for analysis.

But the analysts do not only listen to the sounds, they look at sonograms, which show frequency (which we hear as pitch) over time. When they find right whale activity, they pass on the information to a service that alerts ships nearby.

In case you’ve an interest in trying your eyes and ears at analyzing some sonograms, the same methods are used by citizen scientists on whale.fm, a project that analyzes massive collections of whale calls. Many of the calls on whale.fm are recorded responses to sounds such as sonar, and can be used to learn about whale behavior.

Right Whales are listed as an endangered species on the IUCN Red List, based on their evaluation of the whale from 2008. The whales were once hunted extensively, partly for the ease of retrieving resources from their bodies—upon death, they float.

'Catch of the day' from the UK National Archives

Even decades after international protection from commercial whaling in 1935, their populations have not recovered. In modern days, they are threatened by ship strikes, since ship speeds and activity increased between 1950 and 1970.

Though a restriction placed in 2008 keeps large vessels traveling along the east coast to 10 knots or lower, a sunset clause may end these restrictions in December 2013. NOAA and the National Marine Fisheries Service have proposed to make this law permanent, and have lately been reviewing comments collected from the summer on this matter.

Between shipping restrictions, traffic reroutes, and alerts, researchers have seen an 80-90% decrease in ship strikes. Efforts similar to these are now being made off the coast of California, where blue whales have often been hit by ships coming toward San Francisco and LA.

Related Posts Plugin for WordPress, Blogger...

Creative Commons License
Sea Sounds, Ship Strikes, and Cetacean Small Talk by PLOS Blogs Network, unless otherwise expressly stated, is licensed under a Creative Commons Attribution 4.0 International License.

This entry was posted in bioacoustics, oceanography and tagged , , , . Bookmark the permalink.

Comments are closed.