Good start with fin whales

SOCAL-BRS is now operational for our second field phase of 2015. We are working with several research vessels including the Truth out of Santa Barbara and have been searching the coastal and offshore waters for our focal species. These include endangered blue and fin whales as well as beaked whales and Risso’s dolphins. Again, you can find much more information about our objectives and methods in the SOCAL-15 Public Summary linked from the SOCAL-15 page in the drop down menu on the SOCAL-BRS main page.This blog will serve to provide short updates of our field progress.

The first few days have seen a few good things, but honestly a fair amount of area covered without a lot of focal animals. The very warm surface ocean temperatures you may have been reading about almost certainly has a lot to do with that and we are simply not seeing many large whales feeding in areas where we commonly see them. This is proving a little challenging, but the approach on this project has always been to have contingency areas and focal species. Accordingly, we have moved to some slightly more offshore areas. Yesterday we tagged a Risso’s dolphin but the tag was off quickly and today we had some good success in managing to tag an adult fin whale with an acoustic and movement recording tag (see below – credit: J. Calambokidis taken under NMFS permit # 14534).

DTAG fin whale_Calambokidis

We hope to move a little further offshore tomorrow to search some new areas with relatively good weather. If we stay out there our communications are quite limited, but we will update the blog with more information. In the meantime, please do check out the rest of the site for some of our work, including the many recent papers announced and linked from the site resulting from our experimental research on this project.

SOCAL-BRS in the Field – Follow us!

On behalf of all the collaborators and partnering organizations that are a part of the amazing field research effort known as the Southern California Behavioral Response Study (SOCAL-BRS), I would like to make folks who follow our blog aware that we have just started another phase of field work in this continuing project.

You can find more information specifically on this year’s plans and objectives at <> and specifically <>. There is a .pdf public summary describing the work there and many of the dozen peer-reviewed scientific publications from this prolific project are available there. I serve as the Chief Scientist of this project and am willing and completely available to address any questions or comments or requests for reprints or informations <>

We have made an very specific point to be very transparent and open in our interactions and information about this project. The above referenced summary is an example, as is our from-the-field blog which will appear here and will give semi-regular updates on our progress. There will be postings every several days at this site to provide that information, including photos to show focal species and tagged animals. Today was our first day on the water and while the distribution of baleen whales looks to be quite thin right now – owing almost certainly to the quite warm water – we did have visual detections and tag attempts on blue and fin whales and Risso’s dolphins today (but had just one very short attachment).
Thanks for your interest in our work and for following the from the field blog. Please do provide appropriate feedback and comments here or by email.


New SOCAL-BRS publication on fin whale vocalizations



The SOCAL-BRS team is proud to announce the publication of an important new paper on the calling behavior of endangered fin whales (like the one below, tagged with one of the sensors described in the paper – credit J. Calambokidis under NMFS permit #14534).

DTAG fin whale copy

Dr. Alison Stimpert of Moss Landing Marine Laboratory led the study, which provides key baseline information on the calling and kinematic movement behavior of these amazing animals. The reference for this paper and the DOI number is given below – you can freely obtain this paper through Open Access.


Stimpert et al. Animal Biotelemetry (2015) 3:23

DOI 10.1186/s40317-015-0058-3

Sound production and associated behavior of tagged fin whales (Balaenoptera physalus) in the Southern California Bight

Alison K Stimpert1*, Stacy L DeRuiter2,3, Erin A Falcone4, John Joseph5, Annie B Douglas4, David J Moretti6, Ari S Friedlaender7,8, John Calambokidis4, Glenn Gailey4, Peter L Tyack9 and Jeremy A Goldbogen10


1 Vertebrate Ecology Laboratory, Moss Landing Marine Laboratories, Moss Landing, CA, USA.

2 Centre for Research into Ecological and Environmental Modelling, School of Mathematics and Statistics, University of St Andrews, The Observatory, Buchanan Gardens, St Andrews, Fife KY16 9LZ, Scotland, UK.

3 Mathematics and Statistics Department, Calvin College, 3201 Burton SE, Grand Rapids, MI 49546, USA.

4 Cascadia Research Collective, 218 1/2 W.Fourth Ave., Olympia, WA 98501, USA.

5 Ocean Acoustics Laboratory, Department of Oceanography, Naval Postgraduate School, Monterey, CA, USA.

6 Naval Undersea Warfare Center, Newport, RI, USA.

7 Department of Fisheries and Wildlife, Marine Mammal Institute, Hatfield Marine Science Center, Oregon State University, Newport, OR 97365, USA.

8 Southall Environmental Associates, Aptos, CA 95003, USA.

9 Sea Mammal Research Unit, Scottish Oceans Institute, School of Biology, University of St Andrews, East Sands, St Andrews KY16 8LB, Scotland, UK.

10 Department of Biology, Hopkins Marine Station, Stanford University, 120 Ocean View Blvd., Pacific Grove, CA 93950, USA.


The new SOCAL-15 page on is now available at: <>. On this page you will find a public summary of our research plans for 2015 <>.

We expect to have our primary research efforts in August and October-November this year and we will provide a blog announcement of the beginning of the from-the-field blog posts that a number of people have enjoyed following as we report our progress in (near) real time from the field.



Blue whale tagged off Palos Verdes (J. Calambokisis, NMFS permit #14534)



On behalf of the research team collaborating on the SOCAL-BRS project to study the behavior of marine mammals in southern California and their responses to human sounds including military sonar, I am pleased to report the completion of our 2014 annual research report. This includes some work that ran later in the season this year and we recently completed the report and are glad to make it publicly available.

The report is available at <>


Risso’s dolphins in social interactions off California (Credit: B. Southall; NMFS permit #14534)

Within this report we provide details on our activities and accomplishments in 2014. We also reference the increasing number of scientific publications the project has and continues to generate. A number of these papers are referenced in the report and available in our resources page here and linked from the main SOCAL-BRS page available at <>. Any of these are also available by email at


Southall, B. L., J. Calambokidis, P. Tyack, D. Moretti, J, Hildebrand, C. Kyburg, R. Carlson, A. Friedlaender, E. Falcone, G. Schorr, A. Douglas, S. DeRuiter, J. Goldbogen, J. Barlow. (2011). Project report: Biological and Behavioral Response Studies of Marine Mammals in Southern California, 2010 (SOCAL-10).

Southall, B. L., J. Calambokidis, P. Tyack, D. Moretti, J, Hildebrand, C. Kyburg, R. Carlson, A. Friedlaender, E. Falcone, G. Schorr, A. Douglas, S. DeRuiter, J. Goldbogen, J. Barlow. (2012). Project report: Biological and Behavioral Response Studies of Marine Mammals in Southern California, 2011 (SOCAL-11).

Southall, B. L., D. Moretti, B. Abraham, J. Calambokidis, P.L. Tyack. (2012). Marine Mammal Behavioral Response Studies in Southern California: Advances in Technology and Experimental Methods. Marine Technology Society Journal 46, 46-59.

Goldbogen J.A., Calambokidis J., Friedlaender A.S., Francis J., DeRuiter S.L., Stimpert A.K., Falcone E., Southall B.L. (2012). Underwater acrobatics by the world’s largest predator: 360° rolling manoeuvres by lunge-feeding blue whales. Biology Letters 9:20120986.

Southall, B. L., J. Calambokidis, P. Tyack, D. Moretti, J, Hildebrand, C. Kyburg, R. Carlson, A. Friedlaender, E. Falcone, G. Schorr, K. Southall, A. Douglas, S. DeRuiter, J. Goldbogen, J. Barlow. (2013). Project report: Biological and Behavioral Response Studies of Marine Mammals in Southern California, 2012 (SOCAL-12).

DeRuiter S.L., Southall B.L., Calambokidis J., Zimmer W.M.X., Sadykova D., Falcone E.A., Friedlaender A.S., Joseph J.E., Moretti, D., Schorr G.S., Thomas L., Tyack P.L. (2013). First direct measurements of behavioural responses by Cuvier’s beaked whales to mid-frequency active sonar. Biology Letters 9: 20130223.

Goldbogen J.A., Southall B.L., DeRuiter S.L., Calambokidis J., Friedlaender A.S., Hazen E.L., Falcone E.A., Schorr G.S., Douglass A., Moretti D.J., Kyburg C., McKenna M.F., Tyack P.L. (2013). Blue whales respond to simulated mid-frequency military sonar. Proceedings of the Royal Society B: 20130657.

Yack, T.M., J. Barlow, J. Calambokidis, B. Southall, S. Coates. (2013). Identification of previously unknown beaked whale habitat in the Southern California Bight using a towed hydrophone array. J. Acoust. Soc. Amer. 134, 2589-2597.

Southall, B. L., J. Calambokidis, P. Tyack, D. Moretti, A. Friedlaender, E. Falcone, G. Schorr, K. Southall, A. Douglas, S. DeRuiter, J. Goldbogen, J. Barlow. (2014). Project report: Biological and Behavioral Response Studies of Marine Mammals in Southern California, 2013 (SOCAL-13).

Friedlaender A.S., Goldbogen, J..A. Hazen E.L., Calambokidis, J.A., Southall, B.L. (2014). Feeding performance of sympatric blue and fin whales exploiting a common prey resource. Marine Mammal Science. DOI: 10.1111/mms.12134.

Goldbogen, J. A., A. K. Stimpert, S. L. DeRuiter, J. Calambokdis, A. S. Friedlaender, G. S. Schorr, D. J. Moretti, P. L. Tyack, B. L. Southall. (2014). Using accelerometers to determine the calling behavior of tagged baleen whales. The Journal of Experimental Biology, jeb-103259.

Stimpert, A. K., DeRuiter, S. L., Southall, B. L., Moretti, D. J., Falcone, E. A., Goldbogen, J. A., Friedlaender, A., Schorr, G.S., & Calambokidis, J. (2014). Acoustic and foraging behavior of a Baird’s beaked whale, Berardius bairdii, exposed to simulated sonar. Scientific Reports, 4: 7031. DOI: 10.1038/srep07031.

Goldbogen, J. A., Hazen, E. L., Friedlaender, A. S., Calambokidis, J., DeRuiter, S. L., Stimpert, A. K., & Southall, B. L. (2014). Prey density and distribution drive the three‐dimensional foraging strategies of the largest filter feeder. Functional Ecology. DOI: 10.1111/1365-2435.12395.

B. Southall Delivers Visionary Research Seminar on SOCAL-BRS at ONR S&T Expo


Dr. Brandon Southall gave an invited “Visionary Research” presentation at the recent ONR Science and Technology Expo in Washington D.C. This expo highlights cutting edge research and innovative technology supported by ONR. Given their long-standing support of marine mammal research in a wide variety of areas, including sound and it’s potential effects. Dr. Southall’s lecture covered a variety of these issues but focused primarily on the technological and methodological innovations made in the SOCAL-BRS project. More information on the S&T expo is available at <> and a .pdf of Dr. Southall’s presentation is available on request <>.

New SOCAL-BRS publication on foraging kinematics and prey distribution of blue whales


On behalf of the SOCAL-BRS project, I am happy to announce the publication of another paper resulting from our work. Lead by Dr. Jeremy Goldbogen of Stanford’s Hopkins Marine Station with a number of colleagues from the SOCAL-BRS team, this paper focuses on the fine-scale kinematics of foraging behavior in endangered blue whales and how they change as a function of prey distribution. These data provide both a better basic understanding of behavior in these remarkable, largest-ever animals, but also critical baseline information from which the potential consequences of disturbance from human activities may be determined. The reference for the paper is given below as well as the summary. The .pdf is available on request from

Goldbogen, J. A., Hazen, E. L., Friedlaender, A. S., Calambokidis, J., DeRuiter, S. L., Stimpert, A. K., & Southall, B. L. (2015). Prey density and distribution drive the three‐dimensional foraging strategies of the largest filter feeder. Functional Ecology. DOI: 10.1111/1365-2435.12395.


1. Despite their importance in determining the rate of both energy gain and expenditure, how the fine-scale kinematics of foraging are modified in response to changes in prey abundance and distribution remain poorly understood in many animal ecosystems.

2. In the marine environment, bulk-filter feeders rely on dense aggregations of prey for energetically efficient foraging. Rorqual whales (Balaenopteridae) exhibit a unique form of filter feeding called lunge feeding, a process whereby discrete volumes of prey-laden water are intermittently engulfed and filtered. In many large rorqual species the size of engulfed water mass is commensurate with the whale’s body size, yet is engulfed in just a few seconds. This filter-feeding mode thus requires precise coordination of the body and enlarged engulfment apparatus to maximize capture efficiency.

3. Previous studies from whale-borne tags revealed that many rorqual species perform rolling behaviours when foraging. It has been hypothesized that such acrobatic manoeuvres may be required for efficient prey capture when prey manifest in small discrete patches, but to date there has been no comprehensive analysis of prey patch characteristics during lunge feeding events. We developed a null hypothesis that blue whale kinematics are independent of prey patch characteristics.

4. To test this hypothesis, we investigated the foraging performance of blue whales, the largest filter-feeding predator and their functional response to variability in their sole prey source, krill using a generalized additive mixed model framework. We used a combination of animal-borne movement sensors and hydroacoustic prey mapping to simultaneously quantify the threedimensional foraging kinematics of blue whales (Balaenoptera musculus) and the characteristics of targeted krill patches.

5. Our analyses rejected our null hypothesis, showing that blue whales performed more acrobatic manoeuvres, including 180° and 360° rolling lunges, when foraging on low-density krill patches. In contrast, whales targeting high-density krill patches involved less manoeuvring during lunges and higher lunge feeding rates.

6. These data demonstrate that blue whales exhibit a range of adaptive foraging strategies that maximize prey capture in different ecological contexts. Because first principles indicate that manoeuvres require more energy compared with straight trajectories, our data reveal a previously unrecognized level of complexity in predatorprey interactions that are not accounted for in optimal foraging and energetic efficiency models.

New Publication on Detection of Complex Sounds in Seals and Sea Lions

Complex masking
On behalf of lead author Kane Cunningham, we would like to provide some information on our recent paper on the detection of complex sounds by seals and sea lions.  The goal of this study was to test how auditory data predict detection of complex sounds in quiet and noisy conditions.  Our results indicate that pinnipeds may utilize certain common features of natural sounds to enhance detectability (the key figure demonstrating these results is shown above).  We believe that this study is relevant given current efforts to predict the effects of anthropogenic noise on marine mammal species. This paper is available online through JASA or a .pdf may be obtained by request from
“Auditory sensitivity of seals and sea lions in complex listening scenarios.”
 Cunningham, K. A., Southall, B. L., & Reichmuth, C.
 The Journal of the Acoustical Society of America136(6), 3410-3421 (2014).
Standard audiometric data, such as audiograms and critical ratios, are often used to inform marine mammal noise-exposure criteria. However, these measurements are obtained using simple, artificial stimuli—i.e., pure tones and flat-spectrum noise—while natural sounds typically have more complex structure. In this study, detection thresholds for complex signals were measured in (I) quiet and (II) masked conditions for one California sea lion (Zalophus californianus ) and one harbor seal (Phoca vitulina ). In Experiment I, detection thresholds in quiet conditions were obtained for complex signals designed to isolate three common features of natural sounds: Frequency modulation, amplitude modulation, and harmonic structure. In Experiment II, detection thresholds were obtained for the same complex signals embedded in two types of masking noise: Synthetic flat-spectrum noise and recorded shipping noise. To evaluate how accurately standard hearing data predict detection of complex sounds, the results of Experiments I and II were compared to predictions based on subject audiograms and critical ratios combined with a basic hearing model.  Both subjects exhibited greater-than-predicted sensitivity to harmonic signals in quiet and masked conditions, as well as to frequency-modulated signals in masked conditions. These differences indicate that the complex features of naturally occurring sounds enhance detectability relative to simple stimuli.

New SOCAL-BRS Publication on Baird’s Beaked Whale Behavior

Baird's Beaked whale


We are pleased to announce a recent publication from the SOCAL-BRS project on the basic behavior and responses to simulated military sonar in a Barid’s beaked whale. These data were particularly significant in being the first high-resolution movement and acoustic measurements for any individual of this species. The photo above (Taken under NMFS permit #14534-2; credit A. Douglas) shows the subject described in the feature being tagged.  The reference for this paper and abstract are given below. A .pdf copy is available on request from: <> or <>.


Stimpert, A. K., Stacy Lynn DeRuiter, B. L. Southall, D. J. Moretti, E. A. Falcone, J. A. Goldbogen, Ari Friedlaender, G. S. Schorr, and John Calambokidis. “Acoustic and foraging behavior of a Baird’s beaked whale, Berardius bairdii, exposed to simulated sonar.” Scientific reports 4 (2014).

Beaked whales are hypothesized to be particularly sensitive to anthropogenic noise, based on previous

strandings and limited experimental and observational data. However, few species have been studied in

detail. We describe the underwater behavior of a Baird’s beaked whale (Berardius bairdii) from the first

deployment of a multi-sensor acoustic tag on this species. The animal exhibited shallow (23 +/- 15 m max

depth), intermediate (324 +/- 49 m), and deep (1138 +/- 243 m) dives. Echolocation clicks were produced with

a mean inter-click interval of approximately 300 ms and peak frequency of 25 kHz. Two deep dives included

presumed foraging behavior, with echolocation pulsed sounds (presumed prey capture attempts) associated

with increased maneuvering, and sustained inverted swimming during the bottom phase of the dive. A

controlled exposure to simulated mid-frequency active sonar (3.5–4 kHz) was conducted 4 hours after tag

deployment, and within 3 minutes of exposure onset, the tagged whale increased swim speed and body

movement, and continued to show unusual dive behavior for each of its next three dives, one of each type.

These are the first data on the acoustic foraging behavior in this largest beaked whale species, and the first

experimental demonstration of a response to simulated sonar.



20140919-JAC-0004 After a few rough weather days – hot and windy with high seas – we got a break on our last day for this phase of SOCAL-14. It was nice and calm as we worked back towards our end point near LA and we found a number of different animals feeding on some rich aggregations of krill near the oil rigs in the San Pedro Channel – sea lions, dolphins, birds, fish, and minke, humpback, and blue whales. We managed to get two blue whales in the same group tagged simultaneously and follow them for most of the day tracking their movements, behavior, and calling as well. One of these blue whales (a large female who was the lead animal in this pair shown above – taken under NMFS permit #14534, credit J. Calambokidis). We completed a successful experimental sequence with both whales who continued feeding, although it was halted slightly early when a sea lion swam close enough to the sound source that we had to terminate the experiment because of our permit mitigation requirements. Sea lions especially seem to be quite unaffected by and possibly even attracted to the sound source we use, which is an interesting observation even though they are not the direct subjects. We have an incredibly talented and dedicated group of professionals on this project. We cover a lot of water in sometimes rough seas and work with some of the most challenging animals on earth to study. We have tagged 18 animals of 4 different species with 21 tags of 3 types and conducted 10 complete experimental sequences in SOCAL-14 thusfar. The breadth and amount of new knowledge, publications, and guidance for management decisions regarding the conservation and protection of marine mammals that has come from this project is entirely the result of this remarkable team. Many of them are shown in the photo below and we encourage you to check out more of what many of these folks do outside of the BRS project by linking to some of the websites of all our partners (notably, but see the many other partners listed on and the partner links on the right hand side). We also want to acknowledge the support, cooperation, and willingness to ask hard questions by our sponsors at the U.S. Navy’s Living Marine Resources Program and the Office of Naval Research and our partners in various parts of the Navy. We have a two month hiatus until a final phase of SOCAL-14 in November. Thanks so much to those of you that have and continue to follow the blog and send feedback and questions. GroupPhoto_0019


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

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