1. COSA Committee Meeting Proposed by Alaska Region: Carol Fairfield
June 22-23, 2017
Presentation by: Drs. Erica Staaterman & Jill Lewandowski, PhDs Bioacoustician/Environmental Assessment Chief
Proposed by Alaska Region: Carol Fairfield
Ecologist
Contact
(907)
This study was proposed by Carol Fairfield in the Alaska Region. She could not be here today, so BOEM’s Bioacoustician, Dr. Erica Staaterman and her supervisor, Dr. Jill Lewandowski, will make this presentation due to their background in marine acoustic issues. Carol’s contact information is provided here, and the Alaska Studies Chief Cathy Coon is also available for further discussion.
So you can see right from the start that this project is a collaboration between HQ and the Alaska Region, and the Renewables Program has also expressed support and interest in this far-reaching study.

2. BOEM Information Need:
Generation of Synthetic Audiograms by Applying Finite Element Modeling to CT Scans for Baleen Whales & Walrus
BOEM Information Need:
Assess potential impact of anthropogenic noise on marine mammals
Results could be applied across all BOEM Regions- dependent on the species
Date Information is Required:
The three year project would provide information for our environmental analysis on completion
Varies by Region – used in EIS, EA, ITR, LOA, BiOps
The title is: Generation of Synthetic Audiograms by Applying Finite Element Modeling to CT Scans for baleen whales &/or Pinnipeds
I will explain terms in the title as I progress through the slides.
BOEM, and any other agencies and groups involved in marine activities that produce noise, must assess potential impacts of such noise on marine mammals that could be found in the area. This applies to all areas and marine mammals worldwide, and thus the results from this study will be applicable to all BOEM regions in which a particular species is found. It will likewise greatly increase the state of knowledge relative to the hearing ranges of species, particularly baleen whales, that might otherwise not be obtainable due to their size and approachability.
Information that will be obtained during this study will be used in numerous NEPA-related and incidental take/harassment actions, many of which are listed here.

3. Background Relationship with Previous Work/Efforts:
Expands on NOAA Fisheries Acoustic Guidance, modification under review
Relationship with Concurrent/Future Efforts:
Logical extension of ONR sponsored demonstration of FEM technique applied to a fin whale head, and recently an entire minke whale
Other Relevant Information:
May be able to apply technique to museum specimens, vastly expanding species for analysis
Previous efforts undertaken by BOEM, NOAA Fisheries, the Navy, industry and many other groups have begun to gain familiarity with hearing ranges and thresholds of numerous toothed whale species, but precious little is know relative to the larger baleen whales and some of the other ice-obligate pinnipeds. NOAA Fisheries currently has updated Acoustic Guidance criteria currently out for review. As many of you know, potential effects of noise on marine mammals has been a concern for years, though measuring the hearing capabilities of these large, and often unapproachable species has been a stumbling block for years.
Until now…….
ONR sponsored a new technique, specifically applying Finite Element Modeling (FEM) to get to this information through analyses of cat scans obtained using equipment designed for testing rockets. This machine is large enough to be able to scan a large whale head, and even an entire whale. As this technique is being developed, it appears that the researchers may be able to use properly prepared museum skeletons and skulls, which will greatly expand the species which we may be able to apply this to.
So let’s get into the specific objectives and methodology.

4. Study Objectives
Derive hearing sensitivity & sound reception mechanisms by analyzing CT scans using finite element modeling to visualize what occurs when sound interacts with skull anatomy
Potential species:
Baleen whales – humpback, bowhead
Pinnipeds – walrus
The study objectives are to “Derive hearing sensitivity & sound reception mechanisms by analyzing CT scans with a finite element model to visualize what occurs when sound interacts with skull anatomy”.
The species we are proposing to study are:
Baleen whales – humpback, bowhead
Pinnipeds – walrus
We do have some leeway on the species to apply this to, but accessibility to either very fresh whale heads or properly prepared museum specimens may dictate our initial species to use in this study. Alaska is unique in that we potentially have access to animals harvested for subsistence purposes.

5. Methods
Our goal is to determine hearing sensitivity & directionality for EACH species
Unknown for almost all baleen whales
Bandwidth of repertoires overlap with anthropogenic noise
Applied finite element modeling to CT scans
Ted Cranford & Petr Krysl (2015)
Divide complex shape into network of simpler shapes (FEM)
Use FEM toolkit to visualize interactions between sound and morphology of whale’s head
2 mechanisms that excite bony ear complexes
Bone conduction & pressure
Transform sound pressure cochlea input audiogram
The goal is to determine the Acoustic Threshold of hearing for each species of marine mammals. Some of this has been done by using captive animals to obtain audiograms of what sounds a species can actually hear. If the morphology of an animal is such that it cannot hear a range of frequencies of sound, than it can be assumed that particular sound will have no impact on that species.
Techniques have been developed to obtain audiograms from marine mammals that can be restrained or are held in a captive setting (i.e. auditory evoked potential). But its next to impossible to apply these techniques to the larger whales, like the baleen species. In very basic terms this technique, pioneered by Cranford & Krysl in 2015, combine new computational techniques (specifically Finite Element Modeling) with analyses of morphology in the head of a whale, to determine what sounds an animal is capable of hearing – which is its audiogram.
Using Finite Element Modeling, they were able to visualize interactions that occur throughout the whale’s head when exposed to sound. Very briefly, their results indicated there were two mechanisms that excite the bony ear complexes, bone conduction, found to be the dominant one, and pressure mechanism transmitted through soft tissues. By transforming the sound pressure into cochlea input and then transforming this into a synthetic audiogram.

6. Previous Results
Interactions between sound waves & skull cause deformations that induce motion in the ear complex
Baleen whales have bony ear complexes attached to the skull yielding low frequency sensitivity. Toothed whale ears are suspended from skull – BUT they still have bone conduction (still investigating)
Different head morphology = different skull deformation = different audiograms
Results from the 2015 work indicated that interactions between sound waves and the skull cause deformations in the skull that induce motion in the ear complex. Interestingly, they illustrated that the boney complexes are actually attached to the skull in baleen whales, whereas they are attached only by ligaments and thus not firmly attached to the skull in toothed whales. This accounts for the difference in sensitivity to various frequencies, with baleen whales generally more sensitive to low frequency sounds – which anthropogenic sounds often are. So for each species, the morphology of the head results in differing deformation when exposed to sound, which translate to different audiograms.
This animation illustrates the modeled deformation and thus movement of a fin whale skull for 250 Hz sound wave. Of course these movements are extremely small, so to visualize this, it has been amplified 20,000 times.
Deformation and motion of fin whale skull for 250 HZ incident wave; Amplified 20,000 times

7. Relationship to Strategic Science Questions
Conventional* & Renewable Energy, Marine Minerals Program
How can BOEM best assess cumulative effects within the framework of environmental assessments?
What are the acute and chronic effects of sound from BOEM regulated activities on marine species and their environment?
How can BOEM better use existing or emerging technology to achieve more effective or efficient scientific results?
What affected resources, measures, and systems are best used for long-term monitoring?
How are ocean currents and biota affected by reduced sea ice conditions?*
*Alaska-Specific question addressed
The results of this study will inform all 3 programs which fall under BOEM’s responsibilities, including Conventional Energy, Renewable Energy and Marine Minerals Programs.
In addition, it also will inform 6 of the 9 Strategic Science Questions, and 2 of the 3 Alaska-Specific questions. (List these for the presenter)

8. Implications to BOEM CUTTING EDGE APPROACH TO ACOUSTICS
Incoming sound is not received equally from all directions
Sound in front of whale has greatest amplitude and thus more potential impact
If sound received from behind, it may not have the same level of impact, if at all.
We may be over-estimating “take”
Unnecessary public scrutiny
Lawsuits, etc.
Very important implications to O&G activities
So what are the implications relative to the oil and gas activities?
This study represent THE cutting edge in the assessment of effects of sound on marine mammals.
It turns out that the directionality of the incoming sound is of great importance. If the sound enters the skull from in front of the animal, the greatest amplitude is received, resulting in more potential impact. If the sound is received from the side or behind the animal, it may not have the same level of impact, if at all. The Marine Mammal Protection Act defines “take” as harass, hunt, capture, or kill, or attempt to do any of this. What we are likely doing, is over-estimating the number of marine mammals that are actually harassed or harmed, thus we may be over-estimating “take” of marine mammals. If we are able to prove that these numbers are actually LOWER than once thought, we can eliminate unnecessary public scrutiny, lawsuits, oneness on industry, etc. And THIS could have over-arching implications relative to oil and gas activities.
Thank you for your time, and for your support for this hugely influential study. I would be happy to take questions you might have.