As a graduate student in bioacoustics, my education is interdisciplinary. Bioacoustics is a relatively small field, and (together with my peers) I am challenged to find my way through coursework in ecology, physiology, physics, oceanography, statistics, and engineering to learn the background information that I need to develop and answer research questions. While this challenge (for all young bioacousticians) presents itself a little differently at every university, the information gap is essentially the same. Hence, just over 6 years ago, Dr. Jennifer Missis-Old and Dr. Susan Parks recognized a need to fill this gap for graduate students in bioacoustics and created SeaBASS, a BioAcoustics Summer School.

This year, for the 4th iteration of the week-long program, I was lucky to have the opportunity to attend SeaBASS. I first heard about SeaBASS as a research assistant in Dr. Sofie Van Parijs’s passive acoustics group at the Northeast Fisheries Science Center, but the workshop is limited to graduate students only so I had to wait until I was officially enrolled in grad school to apply. My ORCAA lab-mates, Niki, Selene, and Michelle are all alumni of SeaBASS (read Miche’s re-cap from 2014 here) so by the time I was preparing for my trip to upstate NY this summer to attend, I had a pretty good idea of what was to come.

As expected, the week was packed. I flew to the East Coast a few days early to visit our fearless ORCAA leader, Holger, at the Bioacoustics Research Program at the Cornell Lab of Ornithology, so I was lucky to be somewhat adjusted to EST by the time I arrived at Syracuse on Sunday afternoon. After exploring the campus, it was time for official SeaBASS programming to begin. Our first class, an “Introduction to Acoustics and Proportion”, began early on Monday morning. In the afternoon and through the rest of the week we also learned about active acoustics (creating a sound in the water and using the echo to detect animals or other things) and marine mammal physiology, echolocation, communication, and behavior. We also heard about passive acoustics (listening to existing underwater sounds), including the different types of technology being used and its application for population density estimation. On Friday afternoon, the final lecture covered the effects of noise on marine mammals.

Some SeaBASS-ers testing the hypothesis that humans are capable of echolocation.

In addition to the class lectures given by each instructor, we also heard individual opinions about “hot topics” in bioacoustics. This session was my favorite part of the week because we (the students) had the opportunity to hear from a number of accomplished scientists about what they believe are the most pressing issues in the field. Unlike a conference or seminar, these short talks introduced (or reinforced) ideas from researchers in an informal setting, and among our small group it was easy to hear impressions from other SeaBASS-ers afterward. As a student I spend a lot of my time working alone, my ORCAA labmates are focused on related projects, but we do not overlap completely. The best part of SeaBASS was sharing ideas, experiences, and general camaraderie with other students that are tackling questions very similar to my own.

SeaBASS 2016

Although a full week of class would be plenty to take in by itself, our evenings were also filled with activities. We (students) shared posters (this was mine) about our individual research projects, listened to advice about life as a researcher in the field, attended a Syracuse Chiefs baseball game, and at the end of each day reflected on our new knowledge and experiences over pints. So, needless to say, I returned home to Oregon completely exhausted, but also with refreshed excitement about my place in the small world of bioacoustics research.

Luckily we had beautiful weather for the baseball game!

Most of my time with bioacoustics, thus far, has been with playing sounds – my master’s work with an active acoustic tag – or with identifying odontocete, or toothed whale species, in glider data (typically known as high- or mid-frequency vocalizations).

For my PhD, I’ll be expanding what I know about whale acoustics and looking at baleen whales from glider and float data as well. I started into this the last few weeks and it has been fun, but definitely feels like a step back in time trying to look up literature and see what exactly I am hearing in the data – I’m not used to working with low-frequency sounds.

Low-frequency sounds

What do I mean with low- vs high-frequency sounds? These labels are based on human hearing (of course). Humans (babies!) can typically hear from 20 Hz (hertz) to 20 kHz (kilohertz…hertz*1000; 20 kHz = 20,000 Hz). As we get older we start to lose hearing on the higher end. But marine mammals vocalize both below and above our hearing range. The low/high delineation is “generally” accepted at 1 kHz, and typically baleen whales vocalize below this, and toothed whales vocalized above this. But remember, this is just USUALLY. There are always special cases that don’t follow the trend, and its all relative terms when calling things low and high.

Mellinger_etal_2007_fig1

This figure from Mellinger et al. 2007 is a great way of see where certain species typically vocalize. (Click he figure to link to the PDF of the paper and zoom in)

Looking at sounds

So since some whales make sounds below my hearing range, and some make sounds above, how do I hear them for analysis? Well first of usually I am identifying sounds by looking at them, at a spectrogram (we’ve posted those before right?).

Then sometimes I need to listen AND look to identify what the sound is, or gather more info about it. Wonderfully there is a work around. For really LOW sounds, you can play  them faster, and then that increases the perceived frequency, so you can hear it. Vice versa, for really HIGH sounds, you can play them at half speed, which changes the perceived frequency, and then you can hear them. Does anyone remember Yakbaks? Speeding up your voice makes you sound like a chipmunk, slowing it down makes you sound like…a whale?

 

If you are interested in hearing some baleen whale sounds, sped up so you can hear them, look here: http://cetus.ucsd.edu/voicesinthesea_org/species/baleenWhales/blue.html

You’ll see that on the spectrogram it says *recording plays at 6 times normal speed for better listening.

But this one (http://cetus.ucsd.edu/voicesinthesea_org/species/beakedWhales/cuviersBeaked.html) is played at 1/10th the speed so you can hear it!

How high can you hear? I lose the signal at about 17 kHz 🙁