Nav: Home

'Mic check' for marine mammals

November 30, 2016

Washington, D. C. November 30, 2016 -- Hearing is a vital sense for marine mammals who use it to forage, communicate and navigate. Many of these mammals produce specific vocalizations that can be used to identify the species and track their locations via acoustic monitoring. Traditionally, scientists have used underwater microphones to listen for marine mammals, either on the seafloor or towed behind a boat. But now scientists can use autonomous underwater vehicles, gliders and floats specially equipped with hydrophones, to listen to marine mammals in ways impossible until now.

The direct comparison of these methods conducted by a team of researchers spanning both U.S. coasts will help us to better collect data to monitor marine life for both conservation and management of protected species.

The use of gliders and floats in passive acoustic monitoring helps address the spatial and temporal tradeoff of stationary and towed instruments.

"Towed instruments provide great spatial coverage. A boat can 'mow the lawn' over a large area in a relatively short period of time, while stationary recorders on the seafloor have great temporal coverage, but they record only within a certain range of the hydrophone," said Selene Fregosi, a researcher at the Cooperative Institute for Marine Resources Studies, Oregon State University and National Oceanic and Atmospheric Administration in Newport, Oregon. "A mobile, autonomous recorder can both cover a large area and survey for weeks or months at a time, without the high cost of operating a large research vessel." Understanding how the methods compare and what their strengths and limitations are is a key to the monitoring of sea life.

During the 172nd Meeting of the Acoustical Society of America and the 5th Joint Meeting with Acoustical Society of Japan, being held Nov. 28-Dec. 2, 2016, in Honolulu, Hawaii, Fregosi will explain how the research team tested the two methods simultaneously by deploying their glider and float in the area where cabled, bottom mounted hydrophones were installed. The cabled hydrophone array localized where animals were, and by using those locations researchers evaluated the performance of the glider and float. By recording simultaneously on all the different instruments, data on the capabilities of the autonomous systems was collected.

The most challenging factor in this testing was fighting bad weather to deploy and recover the instruments.

"We had a very short window of time we could work in the area of the cabled array when there wasn't a Navy exercise, so we didn't really have much time to wait for good weather days. Plus, we had communication problems with the glider halfway through the deployment," Fregosi said. "We weren't getting regular messages every 6 hours as usual, so going out to recover it was a bit like looking for a needle in a haystack. But we got lucky that the glider managed to communicate right when we needed it to."

The test of how well these instruments can detect different species of marine mammals, and over what distances, is just the first step towards using acoustic data collected by gliders and floats to estimate marine mammal density and abundance. These are critical measurements for conservation and management of these protected species.

The next step is to take these comparisons and use the baseline detection capabilities of these instruments to better interpret results in a biological context. Fregosi looks forward to putting these tools to work. "I am hopeful that the use of gliders and other autonomous instruments will become more widespread. They can lead to data collection in areas that weren't feasible to study before," Fregosi said.
Presentation 3pABb3, "Simultaneous recordings of marine mammal calls by a glider, float, and cabled hydrophone array," by Selen Fregosi is at 3:15 p.m. HAST, Nov. 30, 2016 in Room Coral 2.


The 172nd Meeting of the Acoustical Society of America
The meeting is being held Nov. 28-Dec. 2, 2016 in Honolulu, Hawaii


Main meeting website:

Technical program:

Meeting/Hotel site:

Press Room:


In the coming weeks, ASA's World Wide Press Room will be updated with additional tips on dozens of newsworthy stories and with lay-language papers, which are 300-1200 word summaries of presentations written by scientists for a general audience and accompanied by photos, audio, and video. You can visit the site during the meeting at


We will grant free registration to credentialed journalists and professional freelance journalists. If you are a reporter and would like to attend, contact Emilie Lorditch (, 301-209-3029) who can also help with setting up interviews and obtaining images, sound clips, or background information.


A press briefing featuring the acoustics of snapping shrimp and coconut beetles plus, how speech sounds influence female vocal attractiveness will be webcast live from the conference on Wednesday, Nov. 30th from 10 - 11 a.m. HAST in room Iolani I.


The Acoustical Society of America (ASA) is the premier international scientific society in acoustics devoted to the science and technology of sound. Its 7,000 members worldwide represent a broad spectrum of the study of acoustics. ASA publications include The Journal of the Acoustical Society of America (the world's leading journal on acoustics), Acoustics Today magazine, books, and standards on acoustics. The society also holds two major scientific meetings each year. For more information about ASA, visit our website at

Acoustical Society of America

Related Marine Mammals Articles:

Genetic evidence points to nocturnal early mammals
New genetic evidence suggesting that early mammals had good night-time vision adds to fossil and behavioral studies indicating that early mammals were nocturnal.
How chewing like a cow helped early mammals thrive
In a paper published March 21, 2017, in Scientific Reports, David Grossnickle, a graduate student in the Committee on Evolutionary Biology at the University of Chicago, proposes that mammal teeth, jaw bones and muscles evolved to produce side-to-side motions of the jaw, or yaw, that allowed our earliest ancestors to grind food with their molars and eat a more diversified diet.
African elephants may be the shortest-sleeping mammals
African elephants in the wild sleep an average of two hours a day and regularly go nearly two days without sleep, according to a study published March 1, 2017 in the open-access journal PLOS ONE by Paul Manger from University of the Witwatersrand, South Africa, and colleagues.
Are drones disturbing marine mammals?
Marine researchers have made sure that their research drones aren't disturbing their research subjects, shows a report in Frontiers in Marine Science.
'Mic check' for marine mammals
Hearing is a vital sense for marine mammals who use it to forage, communicate and navigate.
Most mammals have a greater life expectancy in zoos
Life in the wild harbors the risk of predation, food shortages, harsh climates, and intense competition.
Herbivorous mammals have bigger bellies
As an international study conducted by the University of Zurich based on 3-D reconstructions of animal skeletons reveals for the first time: Herbivorous mammals have bigger bellies than their usually slim carnivorous counterparts.
Assessing the effects of human-caused activities on marine mammals
Rising levels of noise in the ocean have been identified as a growing concern for the well-being of marine mammals, but other threats such as pollution, climate change, and prey depletion by fisheries may also harm marine mammals and influence their response to additional noise.
Contamination from marine mammals may hamper recovery of California condors
Biologists have discovered high levels of pesticides and other contaminants from marine mammals in the tissues of endangered California condors living near the coast that they say could complicate recovery efforts for the largest land bird in North America.
Mammals diversified only after dinosaur extinction left space
Humans' early mammal relatives likely diversified 66 million years ago, after the extinction of dinosaurs opened up space for animals such as big cats, horses, elephants and eventually apes to evolve.

Related Marine Mammals Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Jumpstarting Creativity
Our greatest breakthroughs and triumphs have one thing in common: creativity. But how do you ignite it? And how do you rekindle it? This hour, TED speakers explore ideas on jumpstarting creativity. Guests include economist Tim Harford, producer Helen Marriage, artificial intelligence researcher Steve Engels, and behavioral scientist Marily Oppezzo.
Now Playing: Science for the People

#524 The Human Network
What does a network of humans look like and how does it work? How does information spread? How do decisions and opinions spread? What gets distorted as it moves through the network and why? This week we dig into the ins and outs of human networks with Matthew Jackson, Professor of Economics at Stanford University and author of the book "The Human Network: How Your Social Position Determines Your Power, Beliefs, and Behaviours".