End SOCAL-15 Phase II

Well we have come to the end of our field effort for the SOCAL-BRS summer 2015 effort. We have had some good accomplishments, including tagging 9 animals of three of our four focal species (fin and blue whales plus Risso’s dolphin – we did not manage to tag a beaked whale this time). We were also able to conduct five full experimental sequences among these tagged animals (including the blue whale pictured below; J. Calambokidis taken under NMFS permit #14534), including one coordinated with a real Navy ship in the course of it’s normal training operation.

Tagged Blue Whale_J Calambokidis

However, this has been among the more challenging periods of effort on this project for a number of reasons. Among them was the predominately offshore and thin distribution of whales off southern California. The very warm waters have brought in a lot of more typically southern species, including lots of tuna, mahi mahi, and hammerhead sharks, but they have also pushed the whales more offshore and to areas further to the north through effects on their prey distribution. Our being offshore so much during this period limited the blog updates and also meant we worked less in some of our more familiar and typical areas such as around Long Beach and Palos Verdes. Lastly, we unfortunately had two of our recording tags fail and were not (yet!) recovered. Last year we lost one and someone kayaking in LaJolla found it. So if you are out down there and see something shiny and gold/black with an antenna popping out of it, make sure to grab it and give us a call!

Two tagged fins_Friedlaender

Many people are required to complete the kind of complex, dispersed, and physically challenging efforts that these projects are. I want to personally thank all of our field team for their dedicated effort. I would also like to thank the crew of the Truth from Truth Aquatics, notably Davey Woodland. We also very much appreciate the continued help, support, and encouragement from Diane Alps and our friends at the Cabrillo Marine Aquiarium. We will be back on the water in a smaller shore-based contingent in about a month and I will pick the blog back up then. We expect to have at least one new paper coming out between now and then so stay tuned. You can find more resources and information on the project through the webpage <www.socal-brs.org> and look for the drop down menus for each year. Or email me personally at Brandon.Southall@sea-inc.net with questions, comments, or to get any reprints of our papers not already available on the site.



Warm Waters and Offshore Whales

SOCAL-BRS is progressing well in some ways, despite the extremely limited distribution of large baleen whales in some of our typical coastal areas. As you may have read, the strong El Nino conditions that are setting up off California have resulted in some very warm water temperatures. As a result, we are seeing a lot more large whales spread out and much further offshore in deeper water and typically in some deeper diving modes where they can be a little harder to approach and tag. We have been in some of the offshore waters and have had some success in tagging and conducting three experimental sequences so far in the first five days of this field phase. We have tagged several fin whales and blue whales (including the one below) and a single Risso’s dolphin (though just briefly on the later).




Tagged Blue Whale_J Calambokidis

DTAG on a blue whale off southern California (J. Calambokidis, permit #14534)


We have been searching all day and night for one wayward tag with some important data on it (if you are off Oceanside fishing and you see something gold floating in the water…). We have also included some longer term TDR kinds of sensors that let us track animals for longer periods but with less resolution and we are using these in concert with the high resolution shorter term tags. The weather forecast for some of the further offshore areas doesn’t look great for the next few days but we will get back out there and hope to have some workable periods. We will report some additional results and post some additional photos in the next few days

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 <www.socal-brs.org> and specifically <http://sea-inc.net/socal-brs/socal-15/>. 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 <Brandon.Southall@sea-inc.net>

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 www.socal-brs.org is now available at: <http://sea-inc.net/socal-brs/socal-15/>. On this page you will find a public summary of our research plans for 2015 <http://sea-inc.net/wp-content/uploads/2015/06/SOCAL15-summary.pdf>.

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 <http://sea-inc.net/assets/pdf/SOCAL14_final_report.pdf>


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 <www.socal-brs.org>. Any of these are also available by email at Brandon.Southall@sea-inc.net


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. http://dx.doi.org/10.1098/rsbl.2012.0986

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. http://dx.doi.org/10.1098/rsbl.2013.0223.

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. http://dx.doi.org/10.1098/rspb.2013.0657

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 <http://www.onr.navy.mil/conference-event-onr/future-force-expo.aspx> and a .pdf of Dr. Southall’s presentation is available on request <Brandon.Southall@sea-inc.net>.

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 Brandon.Southall@sea-inc.net.

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 Brandon.Southall@sea-inc.net.
“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.


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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