Narwhal echolocation beams may be the most directional of any species

November 09, 2016

Analysis of some of the first recordings of wintering narwhals showed that they may have the most directional sonar of any species, according to a study published November 9, 2016 in the open-access journal PLOS ONE by Jens Koblitz from Bioacoustics Network, Germany, and colleagues.

The narwhal is considered one of the Arctic's most sensitive marine mammals: more than 80 percent winter in one place--Baffin Bay--and their summering refuges include Lancaster Sound, which is expected to become a year-round shipping route as the ice retreats with climate change. To get a baseline of narwhal sonar and its use, the researchers recorded the species' echolocation beams at 11 pack ice sites in Baffin Bay, West Greenland, in 2013. Hydrophones were placed at depths between 3 and 18 meters.

The recordings revealed that narwhal clicks are the most directional sonar signal of any species, which may help to reduce echoes from the water or sea ice surface. The researchers also determined click intensities, and found that narwhals scan vertically with sonar during ascents and descents. Besides characterizing narwhal sonar to provide a reference for future acoustic monitoring in the region, the data gathered in this study might be used to distinguish narwhal sonar from that of belugas, the Arctic's other toothed whale. Knowing how narwhals use sound could inform future work on how they might be affected by a changing Arctic environment.

"The data collected in a most challenging environment show that the narwhal emits echolocation clicks with the most directional beam of all echolocators," says Jens Koblitz.
-end-
In your coverage please use this URL to provide access to the freely available paper: http://dx.plos.org/10.1371/journal.pone.0162069

Citation: Koblitz JC, Stilz P, Rasmussen MH, Laidre KL (2016) Highly Directional Sonar Beam of Narwhals (Monodon monoceros) Measured with a Vertical 16 Hydrophone Array. PLoS ONE 11(11): e0162069. doi:10.1371/journal.pone.0162069

Funding: ONR funded the study on a grant to K. Laidre (N00014-11-1-0201). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing Interests: The authors have declared that no competing interests exist.

PLOS

Related Arctic Articles from Brightsurf:

Archive of animal migration in the Arctic
A global archive with movement data collected across three decades logs changes in the behaviour of Arctic animals

The Arctic is burning in a whole new way
'Zombie fires' and burning of fire-resistant vegetation are new features driving Arctic fires -- with strong consequences for the global climate -- warn international fire scientists in a commentary published in Nature Geoscience.

Warming temperatures are driving arctic greening
As Arctic summers warm, Earth's northern landscapes are changing. Using satellite images to track global tundra ecosystems over decades, a new study found the region has become greener, as warmer air and soil temperatures lead to increased plant growth.

Arctic transitioning to a new climate state
The fast-warming Arctic has started to transition from a predominantly frozen state into an entirely different climate with significantly less sea ice, warmer temperatures, and more rain, according to a comprehensive new study of Arctic conditions.

New depth map of the Arctic Ocean
An international team of researchers has published the most detailed submarine map of the Artic Ocean.

Where are arctic mosquitoes most abundant in Greenland and why?
Bzz! It's mosquito season in Greenland. June and July is when Arctic mosquitoes (Aedes nigripes) are in peak abundance, buzzing about the tundra.

What happens in Vegas, may come from the Arctic?
Ancient climate records from Leviathan Cave, located in the southern Great Basin, show that Nevada was even hotter and drier in the past than it is today, and that one 4,000-year period in particular may represent a true, ''worst-case'' scenario picture for the Southwest and the Colorado River Basin -- and the millions of people who rely on its water supply.

Arctic Ocean changes driven by sub-Arctic seas
New research explores how lower-latitude oceans drive complex changes in the Arctic Ocean, pushing the region into a new reality distinct from the 20th-century norm.

Arctic Ocean 'regime shift'
Stanford scientists find the growth of phytoplankton in the Arctic Ocean has increased 57 percent over just two decades, enhancing its ability to soak up carbon dioxide.

Spider baby boom in a warmer Arctic
Climate change leads to longer growing seasons in the Arctic.

Read More: Arctic News and Arctic Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.