Offshore Wind Farms Could Disturb Marine Mammal Behavior

Offshore Wind Farms Could Disturb Marine Mammal Behavior

As the number and size of offshore turbines increase, so does the possible disruption to aquatic life.

Media Contact:
Larry Frum
AIP Media
301-209-3090
media@aip.org

DENVER, May 26, 2022 – When an offshore wind farm pops up, there is a period of noisy but well-studied and in most cases regulated construction. Once the turbines are operational, they provide a valuable source of renewable energy while emitting a constant lower level of sound that has not been fully investigated.

Frank Thomsen, of DHI, will discuss how this constant noise may impact wildlife in his presentation, “Operational underwater sound from future offshore wind turbines can affect the behavior of marine mammals.” The session will take place May 26 at 4:25 p.m. Eastern U.S. as part of the 182nd Meeting of the Acoustical Society of America at the Sheraton Denver Downtown Hotel.

Thomsen and colleagues reviewed published sound levels from operational wind farms to identify trends with turbine size. In general, the larger the turbine, the higher the noise emissions.

However, newer wind farms using quieter driving technology can to a certain extent cancel out the impact of larger turbines. Older gear box technology reaches disruptive levels for marine mammals up to 6.3 kilometers away. In contrast, newer direct drive turbines are expected to only impact animal behavior within a 1.4-kilometer radius.

“It is very unlikely that operational noise will lead to any injury or even hearing impairment, but behavioral changes could be a concern, as our study shows,” Thomsen said. “It’s possible that impact zones of individual turbines overlap, but that still does not mean that the wind farm is a no-go area for marine life. We see harbor porpoises frequently swimming in the vicinity of turbines.”

The long-term consequences of this noise on wildlife are still largely unknown. The impact could depend on the number of turbines and their overlapping affected areas.

In theory, the sound can lead to behavior changes in marine mammals and mask calls from whales, but harbor porpoises are frequently seen swimming in the vicinity of wind farms in Europe, so it may not be as simple as it seems.

“Since offshore wind farms have a relatively long lifespan, and there will be many of them, the potential impacts should not be overlooked,” said Thomsen. “The point of our work is to raise awareness.”

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In the coming weeks, ASA’s Worldwide Press Room will be updated with additional tips on dozens of newsworthy stories and with lay language papers, which are 300 to 500 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 https://acoustics.org/world-wide-press-room/.

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We will grant free registration to credentialed journalists and professional freelance journalists. If you are a reporter and would like to attend, contact AIP Media Services at media@aip.org. For urgent requests, staff at media@aip.org can also help with setting up interviews and obtaining images, sound clips, or background information.

ABOUT THE ACOUSTICAL SOCIETY OF AMERICA
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), JASA Express Letters, Proceedings of Meetings on Acoustics, Acoustics Today magazine, books, and standards on acoustics. The society also holds two major scientific meetings each year. See https://acousticalsociety.org/.

DeepSqueak Tool Identifies Marine Mammal Calls

DeepSqueak Tool Identifies Marine Mammal Calls

User-friendly deep learning model analyzes bioacoustics signals from whales, dolphins

Media Contact:
Larry Frum
AIP Media
301-209-3090
media@aip.org

DENVER, May 23, 2022 – Lurking beneath the ocean’s surface, marine mammals use sound for navigation, prey detection, and a wide range of natural behaviors. Passive acoustic data from underwater environments can provide valuable information on these animals, such as their presence or absence within an area, their density and abundance, and their vocal response to anthropogenic noise sources.

As the size and number of acoustic datasets increase, accurately and quickly matching the bioacoustics signals to their corresponding sources becomes more challenging and important. This is especially difficult in noisy, natural acoustic environments.

Elizabeth Ferguson, from Ocean Science Analytics, will describe how DeepSqueak, a deep learning tool, can classify underwater acoustic signals at the 182nd Meeting of the Acoustical Society of America during her presentation, “Development of deep neural networks for marine mammal call detection using an open-source, user friendly tool.” The session will take place May 23 at 11:25 a.m. Eastern U.S. as part of the conference at the Sheraton Denver Downtown Hotel.

Spectrograms show how acoustic signals of different frequencies vary with time. They look like heat maps, with brighter regions indicating higher sound intensity at that frequency and time. DeepSqueak uses deep neural network image recognition and classification methods to determine the important features within spectrograms, then match those features to specific sources.

“Although we used DeepSqueak to detect underwater sounds, this user-friendly, open source tool would be useful for a variety of terrestrial species,” said Ferguson. “The capabilities of call detection extend to frequencies below the ultrasonic sounds it was originally intended for. Due to this and the capability of DeepSqueak to detect variable call types, development of neural networks is possible for many species of interest.”

DeepSqueak was originally developed to classify ultrasound signals from rodents, but its neural network framework allows the technique to adapt to detect sounds at other frequencies. Ferguson and her team used the method and data from hydrophones on the Ocean Observatories Initiative’s Coastal Endurance Array to detect humpback whales, delphinids, and fin whales, which have highly variable calls with a wide range of frequencies.

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WORLDWIDE PRESS ROOM
In the coming weeks, ASA’s Worldwide Press Room will be updated with additional tips on dozens of newsworthy stories and with lay language papers, which are 300 to 500 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 https://acoustics.org/world-wide-press-room/.

PRESS REGISTRATION
We will grant free registration to credentialed journalists and professional freelance journalists. If you are a reporter and would like to attend, contact AIP Media Services at media@aip.org. For urgent requests, staff at media@aip.org can also help with setting up interviews and obtaining images, sound clips, or background information.

ABOUT THE ACOUSTICAL SOCIETY OF AMERICA
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), JASA Express Letters, Proceedings of Meetings on Acoustics, Acoustics Today magazine, books, and standards on acoustics. The society also holds two major scientific meetings each year. See https://acousticalsociety.org/.

3aAB7 – Modeling the potential for vessel collision with Southern Resident killer whales

Dana Cusano1,*, Molly Reeve2, Michelle Weirathmueller2, Karlee Zammit3, Steven Connell1, David Zeddies2

1 JASCO Applied Sciences (Australia) Pty. Ltd., Capalaba, QLD, 4157, Australia
2 JASCO Applied Sciences (USA) Inc., Silver Spring, MD, 20910, USA
3 JASCO Applied Sciences (Canada) Ltd., Victoria, V8Z 7X8, Canada
* Lead author: dana.cusano@jasco.com

Popular version of 3aAB7 – Modeling the potential for vessel collision with southern resident killer whales
Presented Wednesday morning May 25, 2022
182nd ASA Meeting
Click here to read the abstract

With the rise in global shipping traffic, marine mammals are at an ever-increasing risk of vessel collision. These incidents may result in injury or mortality, which can be especially detrimental to endangered species. Predicting the risk of vessel collisions for a given species through modeling can be a useful way to determine whether protective measures are needed.

The risk of vessel collision is often assessed using statistical models that overlay the the density and distribution of animals with that of vessels. This approach does not typically account for the behavior of the animal, in part due to a lack of information on the specific responses of individual animals to vessels. This can include aversive behavior like moving away from the vessel or changing speed, which could have an important impact on collision estimates.

An alternative approach to measuring the risk of vessel collision is modeling the individual behavior of the animals around the vessels. This type of modeling is often used to estimate the sound exposure of simulated animals, called ‘animats’, that move within computed sound fields. For this study, we built on such a model, the JASCO Animal Simulation Model Including Noise Exposure, which is used primarily for estimating the sound exposure of individual animals. A vessel collision framework was developed for Southern Resident killer whales (SRKWs), an endangered species with a small and declining population size. We chose to model an area in Boundary Pass, British Columbia. This is an important habitat for this species that also encompasses a busy shipping lane. In the model, we included the movement data of real vessels that traveled through the area as well as the modeled sound fields of those vessels. We then incorporated animats into the model, which were programmed to behave like SRKWs based on published high-resolution animal movement data. Lastly, we allowed our simulated animals to avert away from vessels based on factors known to initiate a response in this species: the loudness of vessels, the distance to those vessels, and the total number of vessels. Including aversion allowed the animats to respond increasingly to louder, closer, and multiple vessels by changing their heading, speed, and behavioral state. Animats were considered to be involved in a vessel collision if they got within a calculated encounter area of a modeled vessel despite any aversive reactions.

Conceptual diagram of the sources of disturbance (colored shapes) and their magnitude (color gradient) used to predict the level of aversion that an animat experiences at any time step. The Southern resident killer whale in the diagram represents a snapshot of one time-step in the model.

Animats were mostly able to avoid vessel collision, however a small number came within the encounter area of a vessel and were thus considered to be struck by that vessel. We are now investigating whether there are any patterns in the combinations of factors that lead to these collisions. The next steps in developing the model further will be to incorporate uncertainty, investigate the sensitivity of the behavioral parameters, and incorporate additional data on aversive behavior in SRKWs. The goal of this approach is to determine the scenarios where SRKWs are most at risk of vessel collision. Ultimately, this model can be generalized to model collision risk in other species.

 

Killer Whales Lingering in Newly Melted Arctic Ocean

Killer Whales Lingering in Newly Melted Arctic Ocean

Melting ice opens new predation ground for killer whales as they spend more time in previously neglected territory

Media Contact:
Larry Frum
AIP Media
301-209-3090
media@aip.org

SEATTLE, December 2, 2021 – Killer whales are intelligent, adaptive predators, often teaming up to take down larger prey. Continuous reduction in sea ice in the Arctic Ocean is opening areas to increased killer whale dwelling and predation, potentially creating an ecological imbalance.

During the 181st Meeting of the Acoustical Society of America, which will be held Nov. 29 to Dec. 3, Brynn Kimber, from the University of Washington, will discuss how killer whales have spent more time than previously recorded in the Arctic, following the decrease in sea ice. The talk, “Tracking killer whale movements in the Alaskan Artic relative to a loss of sea ice,” will take place Thursday, Dec. 2, at 5:35 p.m. Eastern U.S.

Killer whales will often traverse to different areas to target varieties of prey. In a study including eight years of passive acoustic data, Kimber and their team monitored killer whale movements using acoustic tools, finding killer whales are spending more time than previously recorded in the Arctic Ocean, despite risks of ice entrapment there. Their readings indicate this change is directly following the decrease in sea ice in the area.

“It’s not necessarily that killer whales haven’t been reported in these areas before, but that they appear to be remaining in the area for longer periods of time,” said Kimber. “This is likely in response to a longer open water season.”

The reduction in sea ice may have opened new hunting opportunities for killer whales if certain species of prey are unable to use the ice to avoid the highly adaptive predator. For example, the endangered bowhead whale is vulnerable to predation by killer whales, likely to increase due to longer open water seasons.

“Although there is high spatial and interannual variability, the September Arctic sea ice minimum is declining at an average rate of 13% per decade, when compared to values from 1981 to 2010,” said Kimber. “Killer whales are being observed in the Chukchi Sea (in the Arctic Ocean) in months that were historically ice covered and more consistently throughout the summer.”

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WORLDWIDE PRESS ROOM
In the coming weeks, ASA’s Worldwide Press Room will be updated with additional tips on dozens of newsworthy stories and with lay language papers, which are 300 to 500 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 https://acoustics.org/world-wide-press-room/.

PRESS REGISTRATION
We will grant free registration to credentialed journalists and professional freelance journalists. If you are a reporter and would like to attend, contact AIP Media Services at media@aip.org. For urgent requests, staff at media@aip.org can also help with setting up interviews and obtaining images, sound clips, or background information.

ABOUT THE ACOUSTICAL SOCIETY OF AMERICA
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), JASA Express Letters, Proceedings of Meetings on Acoustics, Acoustics Today magazine, books, and standards on acoustics. The society also holds two major scientific meetings each year. See https://acousticalsociety.org/.

Echolocation Builds Prediction Models of Prey Movement

Echolocation Builds Prediction Models of Prey Movement

Bats use echoes of own vocalizations to anticipate location, trajectory of prey

Media Contact:
Larry Frum
AIP Media
301-209-3090
media@aip.org

SEATTLE, November 30, 2021 — Bats are not only using their acoustical abilities to find a meal — they are also using it to predict where their prey would be, increasing their chances of a successful hunt.

During the 181st Meeting of the Acoustical Society of America, which will be held Nov. 29 to Dec. 3, Angeles Salles, from Johns Hopkins University, will discuss how bats rely on acoustic information from the echoes of their own vocalizations to hunt airborne insects. The session, “Bats use predictive strategies to track moving auditory objects,” will take place Tuesday, Nov. 30, at 1:50 p.m. Eastern U.S.

In contrast to predators that primarily use vision, bats create discrete echo snapshots, to build a representation of their environment. They produce sounds for echolocation through contracting the larynx or clicking their tongues before analyzing the returning echoes. This acoustic information facilitates bat navigation and foraging, often in total darkness.

Echo snapshots provide interrupted sensory information about target insect trajectory to build prediction models of prey location. This process enables bats to track and intercept their prey.

“We think this is an innate capability, such as humans can predict where a ball will land when it is tossed at them,” said Salles. “Once a bat has located a target, it uses the acoustic information to calculate the speed of the prey and anticipate where it will be next.”

The calls produced by the bats are usually ultrasonic, so human hearing cannot always recognize such noises. Echolocating bats integrate the acoustic snapshots over time, with larger prey producing stronger echoes, to predict prey movement in uncertain conditions.

“Prey with erratic flight maneuvers and clutter in the environment does lead to an accumulation of errors in their prediction,” said Salles. “If the target does not appear where the bat expects it to, they will start searching again.”

By amalgamating representations of prey echoes, bats can determine prey distance, size, shape, and density, as well as identify what they are tracking. Studies have shown bats learn to steer away from prey they deem unappetizing.

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WORLDWIDE PRESS ROOM
In the coming weeks, ASA’s Worldwide Press Room will be updated with additional tips on dozens of newsworthy stories and with lay language papers, which are 300 to 500 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 https://acoustics.org/world-wide-press-room/.

PRESS REGISTRATION
We will grant free registration to credentialed journalists and professional freelance journalists. If you are a reporter and would like to attend, contact AIP Media Services at media@aip.org. For urgent requests, staff at media@aip.org can also help with setting up interviews and obtaining images, sound clips, or background information.

ABOUT THE ACOUSTICAL SOCIETY OF AMERICA
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), JASA Express Letters, Proceedings of Meetings on Acoustics, Acoustics Today magazine, books, and standards on acoustics. The society also holds two major scientific meetings each year. See https://acousticalsociety.org/.

2pAB4 – Towards understanding how dolphins use sound to understand their environment

YeonJoon Cheong – yjcheong@umich.edu
K. Alex Shorter – kshorter@umich.edu
Bogdan-Ioan Popa – bipopa@umich.edu
University of Michigan, Ann Arbor
2350 Hayward St
Ann Arbor, MI 48109-2125

Popular version of 2pAB4 – Acoustic scene modeling for echolocation in bottlenose dolphin
Presented Tuesday Morning, November 30, 2021
181st ASA Meeting
Click here to read the abstract

Dolphins are excellent at using ultrasound to discover their surroundings and find hidden objects. In a process called echolocation, dolphins project outgoing ultrasound pulses called clicks and receive echoes from distant objects, which are converted into a model of the surroundings. Despite significant research on echolocation, how dolphins process echoes to find objects in cluttered environments, and how they adapt their searching strategy based on the received echoes are still open questions.

Fig. 1. A target discrimination task where the dolphin finds and touches the target of interest. During the experiment the animal was asked to find a target shape in the presence of up to three additional “distraction” objects randomly placed in four locations (red dashed locations). The animal was blindfolded using “eye-cups”, and data from the trials were collected using sound (Dtag) and motion recording tags (MTag) on the animal, overhead video, and acoustic recorders at the targets.

Here we developed a framework that combines experimental measurements and physics-based models of the acoustic source and environments to provide new insight into echolocation. We conducted echolocation experiments at Dolphin Quest Oahu, Hawaii, which consisted of two stages. In the first stage, a dolphin was trained to search for a designated target using both vision and sound. In the second stage, the dolphin was asked to find the designated target placed randomly in the environment in the presence of distraction objects while “blind-folded” using suction cups, Fig. 1. After each trial, the dolphin was rewarded with a fish if it selected the correct target.
Target discrimination tasks have been used by many research groups to investigate echolocation. Interesting behavior has been observed during these tasks. For example, animals sometimes swim from object to object, carefully inspecting them before making a decision. Other times they swim without hesitation straight to the target. These types of behavior are often characterized using measurements of animal acoustics and movement, but how clutter in the environment changes the difficulty of the discrimination task or how much information the animals gather about the acoustic scene before target selection are not fully understood.
Our approach assumes that the dolphins memorize target echoes from different locations in the environment during training. We hypothesize that in a cluttered environment the dolphin selects the object that best matches the learned target echo signature, even if it is not an exact match. Our framework enables the calculation of a parameter that quantifies how well a received echo matches the learned echo, called the “likelihood parameter”. This parameter was used to build a map of the most likely target locations in the acoustic scene.

During the experiments, the dolphin swam to and investigated positions in the environment with high predicted target likelihood, as estimated by our approach. When the cluttered scene resulted in multiple objects with high likelihood values, the animal was observed to move towards and scan those areas to collect information before the decision. In other scenarios, the computed likelihood parameter was large at only one position, which explained why the animal swam to that position without hesitation. These results suggest that dolphins might create a similar “likelihood map” as information is gathered before target selection.
The proposed approach provides important additional insight into the acoustic scene formulated by echolocating dolphins, and how the animals use this evolving information to classify and locate targets. Our framework will lead to a more complete understanding of the complex perception procedure used by the echolocating animals.