Deep-sea acoustic buoys listen for rare beaked whales off California

cuviers beaked whale
CC BY 2.0 NOAA Photo Library

NOAA's Southwest Fisheries Science Center in La Jolla, California is setting out to learn more about a rare and mysterious group of whales. Beaked whales spend long stretches of time in the far depths of the ocean -- often more than 2,000 meters below the surface -- spending as much as 85 minutes far below before surfacing for air. This behavior means that they are rarely, if ever, seen. In fact, many of the species of beaked whales have never been observed alive.

While scientists don't have a lot of information about this group of whales, they do know that their numbers are declining in the California Current. The best known of the beaked whales, Cuvier's beaked whale, has declined in population from 10,700 in 1981 to 7,500 in 2008.

NOAA is using a unique technology to learn more about these animals that are hard to see. Scientists developed a system of deep-sea acoustic buoys that will drift and listen for the sounds of these mysterious animals. At least 20 of these buoys are being deployed, each with a listening device that descends 330 feet below the surface to record whale songs.

The buoys will drift about 10 nautical miles per day and cover 100 to 200 miles over the course of the 20-day research survey. Researchers will also tow listening devices behind a ship where they will look for any visual evidence of these whales during the 20 days.

"The great advantage of the buoys is that their collective 400 days at sea is like increasing our ship effort by a factor of 10 with very little increase in cost," said Jay Barlow, co-chief scientist of the survey.

NOAA scientists aren't sure what is causing these whales' numbers to decline, but there are many potential threats like changes in the deep-sea food web and human caused pollution and noise. There has been evidence of these whales beaching after military sonar use.

The evidence collected with these high tech buoys will help scientists figure out how many of these whales are off the coast of California and where so that they can better protect the populations.

Deep-sea acoustic buoys listen for rare beaked whales off California
Some species dive so deep, they have never been observed alive.

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