Passive acoustic monitoring (PAM) involves detecting and studying animals using the sounds they make. Its use is widespread for cetaceans since they are highly vocal, and are often below the surface. Using sound allows us to detect them even when we cannot see them.
Part of my Masters research project is going to involve using acoustic detections of harbour porpoises. Since I’ve never done any PAM work before this is pretty daunting! On the advice of my supervisor, I decided to attend Seiche Training’s PAM Level 1 course last week in order to get to grips with PAMGuard, one of the most widely used PAM softwares.
The course is largely designed to qualify offshore operators in real time mitigation during activities such as seismic surveys, where depending on the project, species, and laws of the region, cetacean presence within a certain mitigation zone can temporarily shut down operations.
The course was based in Okehampton and taught by Stephanie Barnicoat from Seiche, who provided not just theoretic knowledge but a lot of practical advice and anecdotes about working offshore. Stephanie said she’d recently redesigned the course to mix up lecture and practical elements a bit more, which I felt worked very well in order to maintain concentration and immediately be applying what was taught.
On the first day we learned about the role of PAM operators, and ran through the common sounds of different cetacean orders and species. We practiced differentiating ‘biological’ clicks from ambient noise using waveform and Wigner plots and using PAMGuard to localise animals both automatically and manually.
We started the second day by getting out the PAM equipment and setting it up in the classroom, which gave me a much better idea of how the whole system worked (I’m not entirely sure what I thought a hydrophone looked like, but I was wrong). A hydrophone array is plugged (usually via a massive extension cable) into a PC with a low and high frequency soundcard. This is set up with two monitors, generally split into low and high frequency detection modules. The low frequency sounds are also output to headphones.
We then spent most of the day building our own ‘psf’ (PAMGuard settings file), ensuring that we would have the ability to set up the program from scratch if struck by technical issues. This was also very helpful in terms of understanding what the software is doing, and felt like a natural extension of looking at the hardware in the morning, tracing a vocalisation from the moment it is detected by the hydrophone to the final stage of localisation in the software.
For the last morning we went out onto the boat to put this all into practice! It wasn’t exactly a huge seismic vessel, but it did the job. We all got to practice deploying and retrieving the hydrophone array (this was the most fun bit) and manning the headphones and monitors, mostly listening to boat noise and snapping shrimp. A porpoise was sighted! But sadly, it didn’t seem to have been picked up acoustically. It’s always good fun to get out on a boat, particularly on a mercifully calm day in Plymouth.
Given that this course is designed for real-time mitigation purposes it didn’t provide me with everything I need to know to manage my acoustic data, but it did help me familiarise myself with the user interface of PAMGuard and some of its capabilities, putting me in a much better position to explore further.
I’m also technically a qualified PAM operator now, although not a marine mammal observer (MMO) and I haven’t done any of the other courses required to work offshore… (I want to do the one where you learn to escape from a helicopter underwater just because that sounds like so much fun). It’s a path I’ve considered going down before and I might yet, but one problem at a time. For now I’ve got a Masters to be getting on with.
Cost: £513 (incl. VAT and student discount)
Travel & accommodation: I drove to Okehampton for both days and was able to stay in my flat in Plymouth, so petrol costs only. A bus was provided from Okehampton to Plymouth for the boat day, but I was able to just meet them at the marina.
Food: Plentiful lunch provided, as well as tea, coffee, and biscuits.