SEA Senior Scientist co-authors IUCN Best Practices Publication on Seismic Surveys

SEA Senior Scientist Dr. Brandon Southall and Dr. Doug Nowacek from Duke co-authored a new publication regarding responsible environmental practices for monitoring and mitigation of seismic airgun surveys. The document is entitled  “Effective planning strategies for managing environmental risk associated with geophysical and other imaging surveys.” It was launched at the World Conservation Congress last night in Honolulu. The PDF of the report is attached. It is also available on the IUCN’s Library Portal online:

Brandon Southall to give DOSITS webinar – Wed 16 March




Members of the international regulatory community have an expressed need for training materials on underwater acoustics as well as instructional resources that can be quickly accessed and viewed. To meet this need, the Discovery of Sound in the Sea (DOSITS) Team is facilitating a free, five-part webinar series on topics related to underwater sound.

Two webinars took place in 2015.  The first reviewed science of sound concepts, the second, sound production and reception in marine animals.  These webinars, PDF versions of the webinar presentations, and other associated resources, have been archived to the DOSITS website (

The third webinar will take place on Wednesday, March 16, 2016, at 12:00 pm (U.S. East Coast time).  Dr.’s Dorian Houser and Brandon Southall will review the potential effects of underwater sound on marine mammals.

Interested individuals must register in advance for this webinar.  To register please visit:

To learn more about this webinar series and view other, upcoming webinar dates and speakers, please visit the DOSITS webpage, Webinar Series for Regulators of Underwater Sound.

Questions?  Please contact Holly Morin at


New publication on Heterogenous Prey Distribution and Beaked Whales


Along with my co-authors Kelly Benoit-Bird and Mark Moline, I would like to bring to your attention a paper recently published in Proceedings of the Royal Society of London B (Biological Sciences) entitled Predator-guided sampling reveals biotic structure in the bathypelagic. The full reference, online location, and full abstract are provided below. We are happy to provide .pdf copies of the article on request by email ( or as a professional courtesy.

Brandon Southall


Benoit-Bird KJ, Southall BL, Moline MA. 2016. Predator-guided sampling reveals biotic structure in the bathypelagic. Proc. R. Soc. B 283: 20152457.

We targeted a habitat used differentially by deep-diving, air-breathing predators to empirically sample their prey’s distributions off southern California. Fine-scale measurements of the spatial variability of potential prey animals from the surface to 1200 m were obtained using conventional fisheries echosounders aboard a surface ship and uniquely integrated into a deep-diving autonomous vehicle. Significant spatial variability in the size, composition, total biomass, and spatial organization of biota was evident over all spatial scales examined and was consistent with the general distribution patterns of foraging Cuvier’s beaked whales (Ziphius cavirostris) observed in separate studies. Striking differences found in prey characteristics between regions at depth, however, did not reflect differences observed in surface layers. These differences in deep pelagic structure horizontally and relative to surface structure, absent clear physical differences, change our long-held views of this habitat as uniform. The revelation that animals deep in the water column are so spatially heterogeneous at scales from 10 m to 50 km critically affects our understanding of the processes driving predator–prey interactions, energy transfer, biogeochemical cycling, and other ecological processes in the deep sea, and the connections between the productive surface mixed layer and the deep-water column.


Marine Mammals and Noise in the Arctic


A recent media piece on noise in the Arctic was published online in Arctic Deeply. SEA Senior Scientist and close colleague Chris Clark of Cornell were among those featured in the article about the science and traditional knowledge of sound and mammal behavior in the Arctic. The link is below as well as several excerpt from the piece.

SE Alaskan horizon

Marine Mammals Unsettled as Arctic Noise Grows

February 19th, 2016 by Cheryl Katz

Industrial noise from ships, offshore development and military activity is exposing Arctic marine mammals to unprecedented amounts of man-made racket. With the retreat of the sea ice, scientists figure the Arctic Ocean will only get louder. Can they muffle the din?

Noise from industrial activities can disturb sea life throughout the world’s oceans, but the problem may be especially acute in the Arctic.Unnatural noise, such as airguns, ship engines, pile drivers and sonar pings, can damage a marine animal’s hearing, mask underwater communication and disrupt critical activities, including migration. The cacophony is compounded in the Arctic by weather noise that was once dampened by the ice blanketing the ocean.

Marine mammals, such as whales, rely on acoustic signals to forage, navigate, find mates and guide other key behaviors. The excess noise from human activities shrinks these animals’ acoustic habitat – the underwater area in which they are able to communicate – and this can hinder reproduction and jeopardize the population’s survival.

The problem can be especially pronounced in the Arctic, where the noise is heightened by the uniformly cold temperature of polar waters. Sound travels over longer distances and is closer to the surface in the Arctic than in temperate oceans – relaying noise across the same depths at which Arctic marine mammals spend most of their time. As a result, noise from a ship engine can be heard dozens of kilometers away and blasts from seismic airgun arrays, which fire several loud pulses a minute to map the ocean floor for oil and gas deposits, are audible for hundreds of kilometers.

“The sound scenes that we’re imposing on the Arctic Ocean are profoundly huge,” said Christopher Clark, a bioacoustics researcher at Cornell University in Ithaca, New York, who has studied bowhead whales in northern Alaska for more than 30 years. The underwater noise levels from airguns, ships and offshore construction can be several times higher than the loudest natural background sounds. “The Arctic situation is critical because man-made noise activities have been relatively infrequent” until fairly recently, Clark said.

Silenced Songs and Thwarted Migration

The effect of noise on marine mammals is determined by a complex interplay of factors. Pitch, frequency, ambient conditions, distance, whether the sound source is moving and other specifics all influence an animal’s response to sound, said Brandon Southall, a bioacoustics researcher at U.C. Santa Cruz and the former director of the U.S. National Oceanic and Atmospheric Administration’s ocean acoustics program.

For example, bowhead whale communication can be disrupted by relatively low noise levels in two distinct ways depending on the total amount of sound they receive over time. A recent study published in the journal PLOS One looked at the reaction of bowheads in the Beaufort Sea to noise from airguns during oil exploration from 2007 to 2010.

But other activities, such as military operations by nations with Arctic borders, appear to be ramping up. And ship traffic will likely increase in places as the sea ice continues to recede.

“I think we’ve learned enough, and there’s been enough responsible development, that it can be done in ways that minimize the effects,” said Southall. For starters, governments could restrict noisy activities during the spring when females with calves are present, and enforce “exclusion zones” that require airguns to stop if species such as bowheads or beluga come close.

“There’s some informed and adaptive ways,” Southall said. “But they need to be supported in a combination of science and traditional knowledge.”

Ocean Noise Feature on California Public Radio

SEA Senior Scientist Dr. Brandon Southall contributed to a recent feature story on ocean noise and some of the monitoring in the Cordell Bank NMSanctuary. The story aired on KQED public radio in San Francisco and is online as the featured post at KQED Science: and the link to the specific post is: The radio story is embedded in the post and there is an audio player at the top. This feature was also included in it’s entirety on the California report on all NPR stations across the state this past weekend.

B. Southall and Expert Working Group Present: “A Risk Assessment Framework to Assess the Biological Significance of Noise Exposure on Marine Mammals”

An expert working group consisting of B. Southall, W. Ellison, C. Clark, and D. Tollit presented a poster summarizing a recently developed risk assessment framework to evaluate the potential significance of noise exposure on marine mammals. The poster was presented at the 21st Conference on the Biology of Marine Mammals in San Francisco. The abstract of the poster is given below and a full version of the poster is available here (or is available from

EWG Framework_SMM posterEWG Framework_FINAL poster

Developing objective and defensible methods to predict potential noise impacts on marine mammals is a very challenging issue with a rapidly evolving scientific basis. An expert working group of biologists, engineers, and acousticians developed a risk-assessment framework for evaluating potential effects of discrete noise exposures. The objective was to develop a systematic, analytical process using certain logical elements of previous assessment methods to predict effects on hearing and behavior, integrated with a biologically relevant framework in which to interpret the significance of those predictions. The scope was deliberately narrow in considering potential effects of seismic airgun surveys on Gulf of Mexico marine mammals. However, the intent was to derive an analytical process that could be both readily modified as new data become available and more broadly applicable. The resulting framework includes several important components: (1) ecologically relevant means of predicting animal distribution; (2) variance in animal density estimates; (3) behavioral aversion in animal movement models; (4) quantitative means of evaluating potential population consequences of disturbance (PCOD) relative to exposure magnitude and duration; and (5) risk-assessment methods that account for uncertainty in key parameters for evaluating disturbance as a function of biological and environmental context. The framework includes sequential stages consistent with current U.S. regulatory assessment methods and additional processes designed to provide biologically meaningful context to interpret potential responses. It benefited from and applied several parallel, recent advances in noise exposure criteria, PCOD modeling, and environmental risk assessment. It represents a significant step in evolving from relatively simplistic methods to more sophisticated approaches that consider biological, environmental, and contextual covariates. Applications of the analytical framework to several real-world scenarios are presented in terms of the framework’s performance and practicality, together with envisaged next steps for advancing the framework. Key progressions include incorporating increasingly sophisticated species-typical social structure, behavioral aversion, and habitat-selection parameters, into movement models and considering multiple noise sources over ecologically relevant spatial and temporal scales.

Brandon Southall’s second guest column in Times publications

The current issue of the Aptos/Capitola-Soquel/Scott’s Valley Times publications include a guest column by SEA Senior Scientist, Dr. Brandon Southall. This is a follow-on article to his 2 November 2015 article on ocean noise, focusing on some of the world-leading research being conducted by local Monterey Bay researchers. The article is on page 24 of the 1 January 2016 issue, which is available at: A specific link to the individual articles will be available in the coming days. The text of the article and links to the featured research projects is given below.


“Local Researchers – Global Studies on Marine Sound” for The Times Publications

By Brandon L. Southall, Ph.D.

SEA & University of California, Santa Cruz

The ocean’s living soundscape reflects teeming life, wild weather, and the deep rumbling of the Earth’s movement. As discussed in my 2 November article, humans are newcomers to this scene but have increasingly added various noises. Some sources are loud and intermittent – others are less intense but chronic around ports and population centers.

How these may negatively effect marine life, especially marine mammals, has been the subject of much research, debate, and regulatory and conservation interest, increasingly so in recent decades. These are complex questions with local, national, and global implications.

We are fortunate to have world-class researchers here in Monterey Bay studying how these amazing animals perceive their environment, behave naturally, and respond to disturbances, including noise. Some work in controlled laboratory settings. Others study wild animals with increasingly sophisticated multi-sensor tools. Still others use mathematical models to predict consequences of disturbance for animal populations.

The University of California, Santa Cruz has long been a leader in studying marine mammals, both at Long Marine Laboratory and around the world. For instance, Dr. Colleen Reichmuth, a research biologist at the Institute of Marine Science, Pinniped Cognition and Sensory System Laboratory studies hearing, visual, and tactile (“feel”) systems in seals and sea lions. Her team carefully measures how these amphibious mammals perceive sounds in quiet conditions, below and above water. Animals are trained to voluntarily participate in hearing studies, telling us what they hear by pressing a paddle, much like elementary school children in hearing screening tests. This allows Colleen and colleagues to measure how they hear and how noise can affect them.

Local researchers are using new technologies to measure marine mammal behavior in the field. Dr. Jeremy Goldbogen of Stanford University’s Hopkins Marine Station has pioneered multi-sensor data sampling and analytical methods using tags attached to individual marine mammals. His collaborative studies have shown detailed features of feeding strategies and behavioral changes in response to noise using high resolution movement sensors, simultaneous acoustic measurements of prey, and even high-definition videos from cameras riding on the backs of whales.

With many other colleagues, we’ve been applying these and other tools in a multi-disciplinary research team studying behavior and the effects of noise, including military sonar, on marine mammals in the Channel Islands The U.S. Navy has supported this research to better understand potential negative effects of their sonars. We have discovered many exciting new aspects of behavior in almost a dozen species, including that many animals clearly respond to such sounds, but their responses depend on the species tested, their behavior at the time, and contextual factors including distance from sound sources.

Many of the broader questions are moving from how individual behavior changes to how disturbance could negatively affect populations. Dr. Dan Costa’s long-standing research program at UC Santa Cruz studies the movement, foraging ecology, and energetics of various marine animals His work integrates aspects of feeding, reproduction, and survival for different species and what levels of disturbance would be required to result in population consequences.

These and other local researchers in our Monterey Bay hotbed of marine science are doing amazing science with local and global implications, increasing our understanding of how animals make, perceive, and respond to noise. Our appreciation has matured beyond more extreme concerns about dramatic loud events to an appreciation for more subtle kinds of responses and what they tell us about responsibly managing our activities in the ocean to ensure we continue to conserve these remarkable animals.

SEA Presentations at 21st Biennial Conference on the Biology of Marine Mammals

Researchers from Southall Environmental Associates were involved in many presentations of cutting-edge marine mammal science at the recent 21st Biennial Conference on the Biology of Marine Mammals in San Francisco. It was an outstanding meeting, culminating with a reception at City Hall (see below) to commemorate the return of the biennial meetings to the city in which the first meeting was held 42 years ago.





Here are some of the abstracts involving SEA Senior Scientist Dr. Brandon Southall:

Southall, B., DeRuiter, S., Friedlaender, A., Hazen, E.L., Goldbogen, J.A., Stimpert, A.K., Langrock, R., Harris, C.M., Thomas, L., Schorr, G., Allen, A., Gailey, G., Falcone, E., Moretti, D., and Calambokidis, J. (2015). Complementary analyses of behavioral responses to sonar in blue whales (Balaenoptera musculus).

Benoit-Bird, K., Arranz, P, Tyack, P.L. Moline, M, and Southall, B. (2015). Predator-prey dynamics in the mesopelagic: Odontocete foraging ecology and antipredatory behavior of prey.

Nowacek, D.P., Clark, C.W., Donovan, G., Gailey, G., Golden, J., Jasny, M., Mann, D.A., Miller, P.J., Racca, R., Reeves, R.R., Rosenbaum, H., Southall, B., Vedenev, A., and Weller, D.W. (2015). Marine seismic surveys and ocean noise: mitigation, monitoring and a plan for international management.

Stimpert, A.K., DeRuiter, S., Falcone, E., Joseph, J., Douglas, A.B., Moretti, D., Friedlaender, A., Calambokidis, J., Gailey, G., Tyack, P.L., Southall, B., and Goldbogen, J.A. (2015). Tagged fin whale call production, associated behavior, and response to anthropogenic sound in the Southern California Bight.

DeRuiter, S., Isojunno, S., Noirot, Stimpert, A.K., Zimmer, W., Leung, M.R., Harris, C.M., Thomas, L., Southall, B., Tyack, P.L., and Miller, P.J. (2015). Sperm whale foraging behavior in response to anthropogenic sound.

Ellison, W.T., Clark, C.W., Mann, D.A., Southall, B., and Tollit, D.J. (2015). A risk assessment framework to assess the biological significance of noise exposure on marine mammals.

Fregosi, S., Klinck, H., Horning, Markus, Mellinger, D.K., Costa, D.P., Mann, D.A., Sexton, K., Huckstadt, L.A., and Southall, B. (2015). Turn down for what: Animal-borne controlled exposures as an innovative tool for dive manipulation in free-ranging marine mammals.

Heenehan, H.L., Bejder, L, Tyne, J.A., Southall, B., Southall, H., and Johnston, D.J. (2015). Using soundscape metrics to describe changes to ambient noise levels in the resting bays of Hawaiian spinner dolphins (Stenella longirostris).

Allen, A., Goldbogen, J.A., Friedlaender, A., Calambokidis, and Southall, B. (2015). An automated lunge detector for baleen whale tag data: application and results for fin whales off Southern California.

Bowers, M., DeRuiter, S.L., Friedlaender, A.S., Nowacek, D.P., Quick, N.J., Southall, B., Read, A.J. (2015). Short-finned pilot whales and Risso’s dolphins respond strongly and divergently to biphonic calls of mammal-eating killer whales.

Harris, C.M., Isojunno, S., Thomas, L., A.S., Southall, B., Miller, P.J., Read, A.J., and Tyack, P.L. (2015). Behavioral responses of cetaceans to anthropogenic sound: A community persective on research priorities and future steps.

Jason, J., Blackwell, S.B., Heide-Jorgense, M.P., Southall, B., Friedlaender, A., Thometz, N.M., and Williams, T.M. (2015). Measuring instantaneous energetic costs in highly maneuverable marine mammals.

Brandon Southall Publishes “Science at Sea” Featured Column (Times Publishing)

SEA President and Senior Scientist was recently invited to publish a featured column in the Science at Sea series in the Aptos, Capitola/Soquel, and Scotts Valley Times newspapers. His piece is available in the current version of these publications and is available online:

026_Sunrise over Catalina_B Southall

The text of the first several paragraphs of the article are given here – reprints are available on request.

Views can be spectacular looking out on the ocean, but our Monterey Bay marine layer often obscures your gaze. And when you dip below the waves and peer into the sea, other than those rare moments of wavering clarity, the darkness is enveloping. But listen to the living underwater soundscape and a whole new world emerges.

From the rhythmic ocean metronome of waves to the clicks and moans of animals and from the rumble of underwater earthquakes to the crack of lightning striking the surface, nature fills the sea with sound. Unlike our early perceptions, there is little silence in the ocean.

Animals have made sound under water for millions of years. They use social calls to track their young and compete with one another. Some even use songs to attract mates. Many species use sound as a general means of orientation – knowing where they are going and if predators are around. Some specialized animals, the dolphins and porpoises, have specialized biosonar sounds like bats to focus in on individual prey while they are feeding.

Sound is so critical to many marine animals, particularly those with backbones, in part because light is so limited in the ocean. While many species can see quite well and some smell or feel things close to them, the physics of water means that making and listening to sounds is simply the best way to accomplish these key life functions.

(please see the above link for more…)



Tagged blue whale in SOCAL-BRS project (Taken under NMFS permit #14534, J. Calambokidis)

We wanted to pass along a recent manuscript on optimal foraging in blue whales as a function of oxygen use and prey density.

Hazen, E., Friedlaender, A., & Goldbogen, J. A. 2015. Blue whales change their foraging strategies relative to prey density. Scientific Advances, e1500469

The abstract is below and the full text is open access and available at:


Terrestrial predators can modulate the energy used for prey capture to maximize efficiency, but diving animals face the conflicting metabolic demands of energy intake and the minimization of oxygen depletion during a breath hold. It is thought that diving predators optimize their foraging success when oxygen use and energy gain act as competing currencies, but this hypothesis has not been rigorously tested because it has been difficult to measure the quality of prey that is targetedby free-ranging animals. We used high-resolution multisensor digital tags attached to foraging blue whales (Balaenoptera musculus) with concurrent acoustic prey measurements to quantify foraging performance across depth and prey density gradients. We parameterized two competing physiological models to estimate energy gain and expenditure based on foraging decisions. Our analyses show that at low prey densities, blue whale feeding rates and energy intake were low to minimize oxygen use, but at higher prey densities feeding frequency increased to maximize energy intake. Contrary to previous paradigms, we demonstrate that blue whales are not indiscriminate grazers but instead switch foraging strategies in response to variation in prey density and depth to maximize energetic efficiency.


Please also see a subset of media resulting from this article (click to link to each)


SOCAL-BRS is a study of basic behavior and responses to controlled sound exposures in a variety of marine mammal species.

Southall Environmental Associates, Inc.

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