For those of you who have followed the from-the-field blog for the Southern California Behavioral Response Study (SOCAL-BRS) before, welcome back and thanks for the interest and support over the past year regarding our publications and presentations. For others of you not familiar with the project, we hope you will find some interesting information about our work through the blog and the project website <>

We have posted a lot of new information, updates, photos, and papers from the front page of the website. Additionally, you can find a drop-down menu with a dedicated page for each field season, including SOCAL-14 which is just beginning now. On this page <> you can find a simply worded public summary document with information about the configuration and objectives of the project for this field season.

We will be on the water for the next ten days starting tomorrow and the weather looks very favorable for the next few days offshore. Look for semi-regular posts about our effort and progress as soon as we are able to get enough internet access to upload some images and summaries. Thanks again, and especially to the program sponsors (U.S. Navy Living Marine Resources Program and Office of Naval Research Marine Mammal Program) for allowing us to be out here doing this work.

Brandon Southall

SOCAL-BRS Chief Scientist



IMO adopts guidelines to reduce underwater noise from commercial ships.


The International Maritime Organization (IMO) recently adopted guidelines to reduce underwater noise from commercial ships.

The new guidelines:

–         recognize that shipping noise can have short-term and long-term impacts on marine life;

–         call for measurement of shipping noise according to objective ISO standards, which are themselves on the verge of adoption;

–         identify computational models for determining effective quieting measures;

–         provide guidance for designing quieter ships and for reducing noise from existing ships, especially from propeller cavitation; and

–         advise owners and operators on how to minimize noise through ship operations and maintenance, such as by polishing ship propellers to remove fouling and surface roughness.

While these (as yet) are voluntary guidelines, not mandatory code, they put the IMO’s imprimatur on noise reduction. Thanks go to the U.S. government, which put the issue on IMO’s agenda and shepherded it through the IMO’s processes, and to Germany, Australia, Spain, the UK, and other governments that supported and helped develop the guidelines.  Thanks also to the coalition of progressive trade groups, research and academic scientists, and NGOs who partnered with member states to get this done, most notably NRDC.  The more difficult work – implementation – lies ahead, but the guidelines are a milestone in the advancement of this issue.

Later this month, there will be a short article in the Journal of Ocean Technology written by Brandon Southall on the history and evolution of this issue, the text of which is given below. If you would like a copy of the IMO document describing what was voted on and the guidelines, please contact


Partnerships for Global Change on Ship Noise

Brandon L. Southall

An international collaboration of scientists, environmental groups, government agencies, and forward-thinking sectors of the shipping industry aims to reduce noise from large ships and associated negative effects on ocean life. And a landmark vote to adopt new guidelines for vessel quieting is just around the corner.

Imagine being beneath the sea with a quiet re-breather system, listening to the underwater world. Among the rushing of waves, snapping shrimp, glumping fish, and whistling dolphins you hear the rumble of a distant ship. You might wonder what it was and whether it was approaching. Or you might recognize it as a symbol of human advancement – a vital flow of industry delivering goods to far corners of the world. To many of us that began working together a decade ago it represented both a challenging, broad-scale concern for sound-sensitive marine life and an opportunity to effect change proactively beyond confrontational divisions that permeate many environmental issues.

Unlike Cousteau’s vision of a silent world, the ocean is naturally noisy – sounds of earthquakes and whales are heard for hundreds of kilometers. But some areas, particularly coastal northern hemisphere regions, have seen major increases in low-frequency (<1000 Hz) noise. The source is human growth and industry, particularly the tens of thousands of commercial ships now continuously plying the seas as our primary global means of distribution.

Public awareness of how sounds affect animals is driven by dramatic but rare events like whale beachings following sonar events. Ship-radiated noise presents less obvious but continuous, broadly-distributed issues. These sounds can affect marine animals in sub-lethal yet significant ways, reducing communication ranges particularly for species reliant on low-frequency sounds to socialize and navigate like whales, seals, and fishes.

Reducing impacts from the aggregate noise of many vessels is challenging given the global scale, typical lifespan of a large ship, and the historical lack of regulation. But progress has been made since the recognition of this as an important conservation matter at the first international symposium on shipping noise convened in 2004 by the U.S. National Oceanic and Atmospheric Administration (NOAA) and workshops on vessel quieting by NOAA and the environmental organization Okeanos – Foundation for the Sea. An international collaboration of proactive representatives of the shipping industry, environmental, government, and scientific communities is pushing solutions forward through the International Maritime Organization (IMO) Marine Environment Protection Committee. This spring, the IMO will vote on new guidelines outlining engineering solutions to reduce incidentally radiated noise from large commercial ships. This is an historic milestone in a long quest toward tangible reduction of the global noise footprint of one of our oldest and most important industries.



New Paper on “200 kHz” sonar with side lobes audible to marine mammals



On behalf of my co-authors, I would like to let you know about a new paper on the audibility of high frequency sonar systems to some marine mammals. We investigated the acoustic “leakage” of energy into side lobes from the 200 kHz center frequency of three commercially-available sonar systems. These active sonar systems were being used in efforts to detect and track marine mammals around a tidal power turbine site and they were not expected to be audible to the animals based on their very high frequency. However, behavioral observations of killer whales suggested they were in fact detecting them. Our acoustic analysis of the systems indicates that there is sufficient downward spread of energy in the side bands to expect that these odontocete cetaceans could in fact hear them. We conclude that received levels at animals would very likely be well below those that could be harmful, but that they could be audible and potentially affect behavior over ranges of hundreds of meters. A reference to the paper, weblink to the Open Access manuscript, and the article abstract are given below. The lead author was PNNL engineer Zhiqun (Daniel) Deng and both he and I would appreciate any comments or questions on the paper.

Deng ZD, Southall BL, Carlson TJ, Xu J, Martinez JJ, et al. (2014) 200 kHz Commercial Sonar Systems Generate Lower Frequency Side Lobes Audible to Some Marine Mammals. PLoS ONE 9(4): e95315. doi:10.1371/journal.pone.0095315

The spectral properties of pulses transmitted by three commercially available 200 kHz echo sounders were measured to assess the possibility that marine mammals might hear sound energy below the center (carrier) frequency that may be generated by transmitting short rectangular pulses. All three sounders were found to generate sound at frequencies below the center frequency and within the hearing range of some marine mammals, e.g. killer whales, false killer whales, beluga whales, Atlantic bottlenose dolphins, harbor porpoises, and others. The frequencies of these sub-harmonic sounds ranged from 90 to 130 kHz. These sounds were likely detectable by the animals over distances up to several hundred meters but were well below potentially harmful levels. The sounds generated by the sounders could potentially affect the behavior of marine mammals within fairly close proximity to the sources and therefore the exclusion of echo sounders from environmental impact analysis based solely on the center frequency output in relation to the range of marine mammal hearing should be reconsidered.

Please also see a PNNL press release on the study:

Greenwire put a short piece out on the paper which you can find at:

Marine mammals can detect sounds from readily available sonar systems — study

Jessica Estepa, E&E reporter

Published: Wednesday, April 16, 2014

Whales and other marine mammals likely can detect sounds from sonar systems that had been considered out of their hearing range, a new finding that scientists say should play into policymaking.

While marine mammals are known to be sensitive to certain sounds emitted by echo sounders, some systems were considered safe because they operated at frequencies of 200 kilohertz — thought to be outside their hearing range.

But the new report published yesterday in the journal PLOS ONE found that these sounders — commercially available for uses such as exploration and navigation — release a second, lower frequency that can be heard by marine mammals.

A team led by study authors Daniel Deng, a chief scientist at the Pacific Northwest National Laboratory, and Brandon Southall, senior scientist and president of Southall Energy Associates Inc., examined the potential impacts of three different systems as part of a bigger assessment on the environmental impact of a proposed tidal energy project in Puget Sound, Wash.

Deng and his team measured the frequencies from the systems in field tests. The data collected was then used to determine whether the lower frequencies would fall into the hearing ranges of marine mammals.

They found that these lower frequencies fell between 90 to 130 kilohertz, well within the audible range for the animals.

While the mammals could detect the sounds at those rates, the study noted that’s below potentially harmful levels, such as causing tissue damage. They also determined that the frequencies could only be heard by animals who were nearby.

Still, researchers said the signals could affect animal behavior. Southall noted that some species, such as harbor porpoises, may leave local areas if they hear the frequencies.

Sonar systems are “commonly exempted” from environmental permitting requirements, according to the study. Both Deng and Southall suggested that policymakers should at least consider whether high-frequency systems may affect animals.

The study provides scientific evidence that policymakers can use, according to Deng. “We believe this should be a consideration for them,” he said.

Southall said other systems should be investigated in similar ways. He added that there is a need for controlled behavioral investigations about cetacean responses.

“We aren’t saying that these are necessarily a major issue, but managers should revisit just flatly excluding things from the regular kinds of consideration and assessment because the frequency on the side of the box says they should be ultrasonic,” Southall, previously with the National Oceanic and Atmospheric Administration, said in an email.



New Paper on Spotted Seal Hearing

We are very happy to announce the recent publication on hearing and the masking effects of noise in spotted seals. This is the first-ever such measurement of hearing in this species both in air and under water. This study was conducted in highly controlled and quiet acoustic environments and the results indicate very acute hearing by these phocid seals both above and below the water. Jillian Sills, a graduate student in Dr. Colleen Reichmuth’s lab at UC Santa Cruz <see: www.pinnipedlab.orb> was the lead author of this seminar article. SEA’s Brandon Southall was fortunate to work with the UCSC team on this important project, which is continuing with the first-ever measurements of how seismic airguns affect the hearing of seals. Related studies are also underway with ringed seals, another important species of Arctic seal, and future work is planned with bearded seals.

Sills, J. M., Southall, B. L., & Reichmuth, C. (2014). Amphibious hearing in spotted seals (Phoca largha): underwater audiograms, aerial audiograms and critical ratio measurements. The Journal of experimental biology217(5), 726-734.

New paper on seismic surveys and mitigation of impacts on marine mammals

SEA Blog,

A paper was on responsible practices for conducting seismic surveys in environmentally sensitive areas was published recently in Aquatic Mammals. The lead author was Dr. Doug Nowacek from Duke University’s Marine Laboratory, who is a close colleague of SEA’s president Brandon Southall who was also an author on the paper. A copy of the .pdf is available with an email to

An IUCN press release on the paper is available at <> and the first part of the release appears below:

Keeping whales safe in sound

A unique collaboration between the oil and gas industry, scientists and conservationists proves a way to minimize seismic survey impacts on rare whales and other species. A step-by-step guide to reducing impacts on whales and other marine species during seismic sea floor surveys has been developed by experts with IUCN’s Western Gray Whale Advisory Panel (WGWAP)and Sakhalin Energy Investment Company Ltd. In the study, published in the journal Aquatic Mammals, the authors present the most thorough, robust and practical approach to minimizing and monitoring the risk of harm to vulnerable marine species when intense sounds are used to survey the sea floor primarily in the search for oil and gas.



Articles on the paper appeared in various news agencies and papers around the world – here are a few links:


We have come to the end of field operations for the SOCAL Behavioral Response Study in 2013 (SOCAL-13). It was a very busy field season with four different periods, each with a slightly different set of objectives and configurations. In May we based from San Clemente Island and worked with colleagues at the SCORE range using a small range vessel to test and operate our new, smaller sound source. In July we used a small boat configuration from several shore bases  in partnership with the U.S. Navy to coordinate with ongoing fleet training operations to conduct the first-ever controlled exposure experiment using an operational vessel with mid-frequency active military sonar. This included a tag deployed on and successful CEE with a real Navy ship and a Cuvier’s beaked whale (above: taken under NMFS permit #14534 by J. Calambokidis).  Later in July and into August we completed another such collaboration with both real Navy sources and our simulated source using a more centralized configuration based from the dive vessel Truth (below with a blue whale, taken under NMFS permit #14534 by J. Calambokidis). Finally, ending just recently was our final research phase of the season, which was based from the Truth and included some additional towed listening systems and the use of simulated sonars.

Across the four phases of SOCAL-13 we collected a total of ~165 hours of high-resolution acoustic and movement tag data from deployments on 2 Cuviers beaked whales, 18 Rissos dolphins, 10 fin whales, 8 blue whales and a minke whale (which was the first successful such deployment on this species). There were a total of 20 full sequences in 2013, involving Cuvier’s beaked whales, fin whales, Rissos dolphins, and blue whales. A total of 32 individual tagged animals were involved in these 20 CEEs, which included 7 simulated sonar (using scaled sound source), 5 actual MFA sonar (using real Navy vessels engaged in ongoing training operations), and 8 control sequences (no sound). Many of these involved multiple tagged animals, including at times individuals of multiple species.

We have made great strides in this work through the dedicated effort of a large number of very talented and hard-working people and with the support of the U.S. Navy and the Office of Naval Research. We continue to analyze and publish the work from this project. Look for continued updates here including publications and reports from the project which will be forthcoming over the coming months. We are hoping and planning for two more field seasons on this project in 2014-15, with an increased emphasis on the use of realistic exposure scenarios. For more information on the project, please look for updates at <>.


Catalina Rissos

It’s been a full few days for SOCAL-BRS, mainly working Rissos dolphins around Catalina Island. We tried to get further offshore yesterday and today but rougher offshore weather pushed us back in. We have had a few firsts the last few days including our first 12+ hour deployment on a Rises and our first experiment with two then three simultaneously tagged Rissos at the same time (see above and below: taken under NMFS permit #14534, credit A. Friedlaender)

We have seen huge amounts of squid (and squid fishing boats) in the shallow waters around the Channel Islands and, not surprisingly, some of the squid-eating predators like Rissos dolphins chasing them in these areas. We have specific rules and protective measures regarding proximity to land and so sometimes have to just observe and obtain baseline diving, feeding, and echolocation behavior on these animals when they are closer in to shore. But that’s just fine as we are adding (rapidly) to the basic understanding of foraging and other behavioral patterns in these amazing animals that are important parts of our southern California bight ecosystems. Six tagged Rissos in three days is a good string for these previously difficult to tag species. We are hoping the weather forecasts for our last few days out here are wrong and we get a chance to add a few more and maybe another fin whale or two.



Fin whale trifecta

We have been focused on baleen whales the last few days in the SOCAL-13 project, primarily fin whales. Over the past three days we deployed ten tags on fin whales (and one on a blue whale) and ran two CEEs plus a full control sequence with a total of seven tagged animals. All of these had accompanying prey imaging and sampling of some of the surface evident krill schools on which the krill were feeding. In several cases we were able to tag two whales in the same group (including the mother-juvenile pair shown above – credit A. Friedlaender taken under NMFS permit #14534). This lets us look at the coordination (or lack thereof) in movement and vocal patterns in these animals, including any possible differential responses to similar sound exposures. We are still hoping to get back offshore to some of the deeper water areas to work with beaked whales and other focal species, but the offshore weather at present in southern California is not particularly agreeing. We will provide subsequent updates on our progress as possible.

START SOCAL-13 PHASE II – Double Rissos

We’re very glad to be back together for this last phase of our SOCAL-BRS project for 2013. We pushed out from Santa Barbara yesterday and came south in pretty good weather. A group of humpback whales has been working in some mixed-species aggregations chasing fish in the Santa Barbara Channel and we came across a few of them right off the bat. We moved on with no tags deployed and searched deeper waters south of Santa Cruz Island. We found two different groups of Cuvier’s beaked whales (Ziphius cavirostris) near Santa Barbara Island and came fairly close to tagging one but didn’t manage to.

Today we had really fantastic weather for most of the day and we searched large areas offshore. We didn’t find any beaked whales but came across quite a few groups of Rissos dolphins (Grampus griseus). There were several good candidate groups and by early afternoon we managed to deploy two tags on adult animals in two different groups. Our controlled exposure experiment (CEE) focused on one group with the second tagged animal about 10 miles away. Tagging and CEE on two simultaneous Rissos dolphins (see tagged Rissos below – taken under NMFS #14534, credit J. Calambokidis) at different ranges is a new accomplishment for us in SOCAL-BRS and a good start to our final field phase over the next two weeks.

For more information on the SOCAL-BRS project, make sure to check out all the resources and photos in our blog and at


SOCAL-13 Phase I End


We have come to the end of the first full research phase for the SOCAL-BRS project in 2013. In terms of our success with the high-priority beaked whale species, this was the most successful period we have had in this project. We had two successful tag deployments (see above – taken under NMFS #14534-2, credit J. Calambokidis) and at least three other very close attempts with multiple groups. We had both successful visual focal follows over many “shallow” dives and acoustic tracking of focal groups through deeper foraging bouts covering many miles. Having multiple groups detected and tracked with multiple tags deployed and a full CEE sequence with workable weather for five straight days well offshore was unprecedented for us as well.

On the days we did not manage beaked whales we had lots of luck with Rissos dolphins (8 total tags, 4 CEEs), fin whales (2 tags, 2 CEEs – below photo taken under NMFS #14534-2, credit J. Calambokidis) and targeted deployments on blue whales (3 tags, 3 CEEs).


Another major development, as described in the public summary for this project linked to the SOCAL-13 page on <>, was our first coordinations with the U.S. Navy to coordinate with already ongoing training operations to have real military sonar systems used as sound sources in our CEEs rather than the small, scaled simulations we have used to this point. Our colleagues at the Navy just issued some additional information on this partnership and have more information about it available in several locations – please see:

Thanks again for following us out here and for the many comments and nice emails I have and continue to receive. We will be back for phase II in September and will resume the from the field blog at that point. We will have some additional updates and information on forthcoming presentations and manuscripts before then likely as well, as we have another paper coming out from the project soon.

Tagged blue whale (see gold DTAG attached to left side of the whale) with our research boat “TRUTH” in the background (taken under NMFS #14534, credit J. Calambokidis)





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.

Reducing environmental impacts from essential human activities requires unique approaches to meet challenging conservation objectives in the 21st century. SEA, Inc. works globally with diverse scientific teams and cutting-edge technologies to provide real-world solutions. Learn more about SEA