Researchers publish scientific papers in very specialized journals that are only read by experts in the field. These papers are usually very technical and complicated to understand for the general public. This is a shame because many people are keen to learn about the research going on in their community. In my opinion, it is important for researchers to be able to explain their research in a layman language accessible to most people. It is hard though... We are trained to be detail oriented, precise and rigorous, and simplifying complicated concepts by leaving out  some of the important details is no easy task. It takes training and practice.

I have been very fortunate be able to follow several great science communication workshops that help acquire these skills. One of them is the science communication workshop by COMPASS which was a game changer for me. It completely changed the way I thought about science communication and really helped when talking to the media. Another, great training was the Three-Minute Thesis (3MT) competition. It is a world-wide competition that challenges graduate students to present their research in just 180 seconds. The presentations must be engaging and understandable by people that have no background in the research area. So, no need to say that in 180 seconds, you don't have any time for complicated details... The competition itself is fun, but what was the most valuable was the training offered beforehand. Several professors from the University of Victoria gave us advice on how to talk in public and provided very useful feedback on how to improve our speech. If you are a graduate student, I highly recommend to participate. I would also highly recommend participating to Skype a Scientist, and/or Pint of Science, to practice your science communication skills. 

My 3MT presentation, entitled "This all sounds fishy...",  was about the Fish Sound Project. You can watch it here.

The two deployments of the XAV array at Ogden Point were successful and allowed us to localize and identify our first fish sounds. Sounds that haven’t been reported before (…more on this later). No need to say that it was a huge relief to finally see the full system operational and working properly! All the development efforts are finally paying out. The deployment operations are also getting much smoother. Everyone is now more comfortable with the whole process and knows exactly what to do. While Ogden point was a great location, it was time to move to another spot with different species of fish and hopefully with less vessel noise.

We chose to deploy at the wreck of the Lord Jim, in Mill Bay since our previous exploratory dive with the ROV showed that it was a site with very good potential (see previous post). From the data we collected at Ogden Point, we know that the XAV array can localize fish sounds in 3D quite accurately. However, it is large and the logistics involved in its deployment can sometime be an issue since the aluminum boat from the lab is not always available. So, we decided to test a compact version of the XAV array that can be deployed from an inflatable boat. It is composed of a smaller acoustic recorder, has four hydrophones (instead of six) and only a single camera (instead of two). The PVC frame is also much lighter. The smaller footprint is great, but of course, there are some drawbacks… we won’t be able to localize as accurately as with the regular XAV array and our field of view will be much more limited. Still, we should be able to collect useful data.

The site is not too far from Victoria and is conveniently located next to an easily accessible beach. After setting up the instruments, Kieran and Brian dove to the shipwreck and I brought the mini XAV array to them with my inflatable boat. Everything went smoothly and the whole process took less than a couple of hours. There were still plenty fish around the shipwreck which was great news! However, we were at the beginning of a phytoplankton bloom and the visibility was poor. We left the mini XAV array in the water for a week and everything worked fine. The visibility obviously was not great, but we still got several fish swimming right in front of the camera. The noise underwater was higher than I had expected, but we still recorded several fish sounds. Overall a successful deployment. This mini array will not replace the XAV array but will allow us to deploy more often and sample more locations.

This blog was originally hosted by the National Geographic Open Explorer platform. However, several months ago, National Geographic decided close the site. They indicated that they would re-open it in January 2020 under a new domain, but it doesn't seem to be happening. This is too bad because it was a really great platform.

Nevertheless, I really enjoyed writing these blog posts on the Fish Sound Project and decided to continue the blog under my website. Many things have happened since the last update, so I will progressively post about what we have been up to since Sep 2019.  There will be cool videos and exciting results ;-) 

In the meantime, If you want to receive email alerts when updates are posted, make sure to enter your email in the text box at the top right and hit "subscribe". Also don't hesitate to post comments. 

More soon!

This is quite an improbable story. Earlier this year we had lost some instruments: a camera and an acoustic recorder. This was quite an unfortunate event, but since then we moved on, learned from our mistakes and improved both the instruments themselves and the way we deploy them. It’s been more than 6 months now that these instruments were likely living their own lives drifting away in the ocean and I had no hope whatsoever to get them back at any point.

On a Tuesday afternoon I received an email from Brian (a lab mate diver who has helped on almost every deployment of the XAV array): “Hey check these pictures, I think this is your camera”. Wait...what? My camera? I open the pictures and yes! That was it! The camera we lost 6 months ago ended up on a beach at Clover point in the south of Victoria, about 50 km from the deployment location. Then Brian tells me the full story. A lady doing her morning walk, found the camera on the beach, picked it up, saw the sticker for the University of Victoria and called the biology department to report it. She didn’t know what to do with it so she just left it somewhere obvious on the rocks so we could come pick it up. Brian and Micah (another lab mate) went straight away to the beach to pick it up but couldn’t find it. So, the camera was lost, found, and lost again… Great…This camera was really playing tricks on us! Fortunately, the same lady called me the next morning to tell me that she found it (again) and took it with her this time. Someone had taken the camera, opened it and left it further down the beach close to a construction site. Amazingly, everything was still intact inside. I was even able to get the video data it collected.

Looking at the footage, we now know what happened to the instrument. After a week of deployment, the current increased substantially, and waves got bigger and bigger which pulled on the line attached to the surface buoy. As a result, the instruments started to drift away by doing little hops. It is good to understand what happened. We are still missing the hydrophones so, these data are not too useful for us, but the good thing is that I was able to salvage all the electronic components and batteries of the camera to build a new one.

Case closed.

​The data we collected at Ogden Point were quite good and we captured fish on both the hydrophones and the video cameras. As expected, the vessel noise was quite important though. So now we are ready to move on to a new location with different fish species and hopefully less noise.

In my list of potential good places to deploy the XAV array was the wreck of the Lord Jim near Mill Bay. The Lord Jim was an old tugboat that sank accidentally many years ago while on anchor. The wreck of the boat is still there and acts as a nice artificial reef. It is supposedly a nice diving spot with lots of fish. It is also in an area with much less boat traffic than Ogden Point.

Before deploying the array and mobilizing all the diving team, I wanted to make sure that it was a good location. So, I went to check it out with my small inflatable boat and the Trident underwater drone. I was not alone this time. Jean-Baptiste, my brother in law, and Helene, his girlfriend, were visiting us from France, so I took them with me to give them a little taste of beautiful British Columbia. The place was absolutely gorgeous and we found many different species of fish including pile perch, stripped perch, yellowtail rockfish, brown rockfish, copper rockfish and spiny dogfish (i.e. little sharks). Definitely a good spot to deploy the XAV array!

Once upon a time while deploying instruments at Ogden Point:

• Brian: "Hey Xav, did you give a name to your hydrophone and camera array ?"
• Me (Xavier): "No, I have not really thought about it, but Morgan said we should call it the Xav array."

 
(laughs)

• Brian: "Well, you know, the A and the V could stand for Audio/Video. Not sure about the X though..."
• Me: "Hum.. that is kind of cool."
• Stan: "What about eXperimental for the X ?"
• Everyone: "Uhhh nice!"

​
That's it, we now have a name! It is now the eXperimental Audio Video array, aka the XAV array ;-)

Team work!

Given the success of the exploratory dive at Ogden Point, it was clear that if was a great spot to deploy the audio and video array. There are many different fish in the area and it is also easily accessible. The only issue with this location is the intense boat traffic. It is close to the cruise ships terminal and is on the main channel leading to the Victoria inner harbor. This is not an issue for the deployment operations and the instrumentation per se, but mostly for the elevated the noise from the boat traffic that could mask the fish sounds we are interested in. Nevertheless, it looked like a great location to get started and a great way to get all of us more comfortable with the deployment/recovery operations and gain confidence with the equipment.

So, we deployed twice off the breakwater at Ogden Point. Once in May and once in June. Both deployments lasted for 10 days. The first deployment had only one camera at the top of the array, while for the second deployment I had built a second camera and placed it on the side of the array to get an additional angle of view and thus facilitate the fish identification.

Despite some windstorms, the array held up very well in place. As the array was deployed close to the breakwater, it was easy for me to go check that everything was fine from land with the Trident (and I did that often…very often). I am happy to report that all instruments worked correctly and that we recorded many fish swimming through the array with the video cameras. Despite being a very noisy environment, we were able to capture fish sounds on the hydrophones and localize them in 3D.

I can’t tell you how much of a relief it is… FINALLY! I am finally collecting the data I was hoping to get many months ago! It took a long time, but it is finally happening. This very encouraging and now we are already planning to deploy the array at other places around Vancouver Island. Hopefully somewhere quieter.

Ogden Point deployments team:

• Skippers: Nick Bohlender, Morgan Black, Jesse Macleod.
• Divers: Kieran Cox, Morgan Black, Brian Timmer, Desiree Bulger, Sean Dimoff, Kristina Tietjen, Niallan O'Brien.
• Dive tenders: Hailey Davies, Garth Covernton.

​The breakwater at Ogden Point is a very famous diving spot in Victoria. Many tourists and locals dive there to enjoy the abundant and diverse marine life. Many different species of fish including five different species of rockfish, sculpins and lingcods. Potentially a great spot to deploy our instruments and record fish sounds. I came there with the Trident to see by myself and I was not disappointed. Big schools of beautiful striped perch, small lingcods and river otters. Definitely a great spot for us. I was amazed to see that the fish didn’t seem to be bothered at all by the Trident.

After losing the equipment earlier this year, it became evident that we had to adjust the way we deploy the array. One major change was to add more ballast, so the array doesn’t get dragged by strong currents. Unfortunately, more ballast also meant trickier deployments. So, it became clear that we needed divers. It added more logistics and paperwork, but I am super excited to have now 3 more awesome people joining the team.

Morgan Black
Morgan is a PhD candidate in marine ecology at the University of Victoria and a Hakai Scholar. She is involved in many research projects, but for her PhD she focuses on the ecology and biodiversity of these amazing ancient First Nations structures called clam gardens. She is a very experienced scientific diver, commercial vessel operator and great underwater photographer. Morgan is co-leading all the diving operations with Kieran. Check her website to learn more about Morgan.

Kieran Cox
Kieran is a PhD candidate, Hakai Scholar, and Smithsonian Link Fellow, in marine ecology at the University of Victoria. His research also focuses on the biodiversity responses to shellfish cultivation in British Columbia. But, he is also involved is many other research projects dealing with the impact of noise on fish, microplastics in marine ecosystems, and coral reef ecology. He is very experienced scientific diver and avid photographer. Kieran is co-leading all diving operations with Morgan. Check out his website here.

Jessica Qualley
Jess is the lab manager in the Juanes Lab at the University of Victoria. Her skill set is impressive from necropsying sixgill sharks, analysing salmon diet, to tagging humpback whales and deploying acoustic equipment. She basically knows how to do everything 😉. She is coordinating the logistics of all our deployment and recovery operations and is also the main boat driver.

I feel extremely privileged to have such talented and fun people join the team!

​It’s been a long time since I posted updates on this page. And the reason is… things have not been going so great. The first 5 months of 2019 have been very challenging for me and I’ve almost reached the point where I wanted to quit my PhD. I was pretty deep into the “Valley of Shit”.

A couple of years ago, we had our weekly lab meeting and one of the post-docs was talking about how hard it can be to be trapped in the “Valley of Shit” during a PhD and she gave some advice on how to get out of it. This “Valley of Shit” is pretty self-explanatory. It is a period in a PhD where about everything goes wrong and things get completely stuck.

​It was the first time I’ve heard that expression and while I understood its meaning, at the time, I was really more amused by that funny-sounding expression than really worried about it. I was pretentious enough to think that because of my experience doing research, this would not happen to me and I would just cruise smoothly along the PhD road. Turns out I was wrong… so very wrong.

While I am working on my PhD, I am also working part-time for a consulting company in underwater acoustics. This arrangement has been working pretty well for me so far and I have usually been able to keep a fairly good balance between work and school. The key is to keep it “part-time”. Back in late 2018, I have naively agreed to lead a couple of big projects at work with very tight deadlines, and that part-time quickly turned in to a full-time. So, I was busy at work during the day, but I was still able to make some progress on my PhD at night. Overall, things were going OK. It was tiring obviously, but I knew it was temporary and I was happy to make progress on both fronts. I managed to fix the issues I had with my camera and also built a second smaller hydrophone array while the other one was getting fixed. So, in late January, I was ready to redeploy my instruments. We picked a new spot off Victoria where several species of rockfish like to hang out and I was excited to finally get my first set of data for my PhD. We deployed the array and came back a week later to pick it up. However, when we came back to the deployment site, we couldn’t find the surface buoy anymore. I searched the sea bottom with the Trident in case the buoy line broke off, but nothing... We even had divers go down, but no luck either. The instrument had either drifted away with strong currents or got picked up by someone… The result is: no instruments, no data… Needless to say, that the morale was pretty low. Not only these instruments are expensive but also rebuilding everything takes a lot of time. All these efforts working crazy hours at night for absolutely nothing... Things got even worst. My wife had a great opportunity to do research on grey whales in Mexico and left in the field for a month. While I was very happy for her, it meant that I had to take care of our two young kids by myself for a month on top of everything else. Kids got very sick (as kids do), work got crazier, my PhD was still going nowhere, and I was really exhausted. Now, I could really appreciate what the valley of shit was. I was definitely there… hands and knees. Ready to give up.

Through this, I have had an amazing support from my friends, family, colleagues and even the local community. Somehow, the fact that I lost my instruments made the local news and I received lots of emails from people trying to help me find my instrument. Even some divers looked for it on their recreational weekend dives. It was really heart warming. I really felt supported through this. Many colleagues also told me stories about how they lost expensive equipment during their PhD, so I wouldn’t feel so bad. All this support really helped.

Things are now slowly getting better. I’ve lost several months of my PhD, but things are starting to progress. I have rebuilt an improved camera system and have successfully deployed (…and recovered) my big hydrophone array. I am now starting to get the data I was hoping to collect many months ago. There are also new awesome people joining the team which is very exciting! More in this soon.

This post was kind of long and dramatic, but I promise, the next ones should be a bit lighter and with some cool videos 😉.

​As I mentioned in previous posts, we want to use the Trident to recover our hydrophone and camera array from the seafloor. While planning for the next deployment, I took some time to perform some tests and added a pole at the front of the Trident with a carabiner. After few iterations, I found a reasonable design that does not affect too much the maneuverability of the Trident and is easy to put together (and repair in the field). Once hooked to the mooring, the carabiner detaches itself from the pole and is closed using a simple quick release mechanism. I tested it in shallow water (5m) off a dock nearby and it worked pretty well. The real test will be to use it in deeper water, but things look promising so far.

Our instruments are working again and we are planning to deploy the fish array in the next few days, as soon as the weather calms down. Stay tuned...

The weather has been absolutely crazy after we deployed the hydrophone array. A severe wind storm caused the cancellation of multiple ferries, delayed many flights, put down a number of trees (causing 1 fatality) and left about 225,000 homes without power across Southern Vancouver Island and the Lower Mainland. Needless to say that I was worried about our mooring, especially with the surface buoy. On the bright side, at least this was a good stress test. If the hydrophone array survived this, I think we could call this deployment a success…

Due to the storm we delayed the recovery trip by a day and went back on the water on Friday morning with Jess and Alex MacGillivray (a good friend and colleague of mine at JASCO) who kindly agreed to come help us. Luckily, the winds had completely died down after the storm and the weather conditions were amazingly good. We couldn’t use the same boat ramp as last time since it was completely blocked off by driftwood that got washed out by the storm (see picture below). Luckily, there is another boat ramp near by that was still accessible. To be honest, at this point, I was prepared to not find the surface buoy and was already thinking about backup plans to get the instruments back. But as we approached the deployment location with the M/V Liber Ero, I could see the orange buoy in the distance. That was a relief… Once at the mooring location, we deployed the Trident to make sure everything was sitting properly on the seafloor and that the lines were not tangled in the PVC frame. It was fairly straightforward to find the hydrophone array on the seafloor. Now that we have more experience with the Trident, I am pretty confident that we will soon be able to deploy the array without a surface buoy and use the Trident to retrieve the instruments. After some heavy lifting, we managed to bring the whole unit back on the boat and go back to shore. Everything looked fine and I was pleased to see that the structure handled very well the harsh conditions of the last few days. Mission accomplished! Time to go back home [...you can imagine myself with a big smile driving my tiny car packed to the roof with all the equipment, plus the big buoy]_

So, that was the good part… now the bad… As soon as I arrived home, I started to download the data. I was excited to see if we had caught any fish on the camera. Unfortunately, my smile and excitement quickly disappeared, and my face progressively turned red. The camera did record video files… but they were all empty. I was devastated. All these efforts to have no video data… Looking at the logs, I saw that all the scripts, battery pack, power management, and buzzer worked well, but there was something wrong with the camera sensor. I am still investigating the exact reason of this failure, but it looks like the camera sensor got damaged during the transit on the boat. As for the acoustics, we collected data on all 6 hydrophones, but one of the channels seems to have issues. Here, again, I am investigating to see how this can get fixed.

To be honest, I was not to keen to write this post and report failure. But I guess it is part of the game. Failure is part of the process. Spending quality time during the Christmas holidays with my loved ones helped me step back and see the positive side of it. Stan, Francis and Rodney were also very supportive. Even though I did not collect good data, this deployment brought to light some issues that need to be fixed to improve the robustness of the system. Overall it was also good to gain experience with the deployment and recovery of the unit. I have more confidence in the structure of the array and in the deployment/recovery process.

Now back to the drawing board to fix all the issues and hopefully we’ll be able to redeploy soon.

Best fishes for 2019!

​Our first deployment site is in Cadboro Bay, close to the University of Victoria. We picked this site because sculpins have been seen there and also because this is a sheltered site. For the first deployment we didn’t really want to go straight in the open ocean. Baby steps.

So, on Monday, Jess Qualley (manager of the Juanes lab and skipper), Katie Inness (Juanes lab assistant), Tristan and I went onboard the M/V Liber Ero to deploy the hydrophone array. The weather was cooperating, and everything went pretty smoothly. One of the challenges was to find out how to fit the array on the tiny boat. It was tight, but we made it work. For this first deployment, we chose to have a surface buoy for the recovery, just to be safe. This might cause some noise if there are big waves, but at this point in the mission we just wanted to make sure we could retrieve the instruments easily. We’ll get braver in a few deployments, once we gain more experience and confidence.

Once everything was deployed, we put the Trident ROV in the water to make sure the array was sitting properly on the seabed. It was only the second time using the Trident (the first time in the ocean). It was neat and reassuring to be able to inspect the array once deployed.

The instruments will stay in the water for 4 days before we come back to pick everything up.

• Camera system
• Hydrophone array
• PVC frame
• Trident ROV

This is it ! We now have everything we need to start real measurements in the ocean. First deployment planned before Christmas.

​This week I received the Trident from OpenROV. I was not expecting it before January, so it was a nice surprise. After getting familiar with the hardware and making all the necessary software updates, I took it on a test dive. I initially wanted to test it in the ocean right by my house but seeing all the kelp floating around made me a little bit anxious. All I wanted to know for this first dive was how hard/easy it was to control the Trident. Until I knew this, getting tangled in kelp didn’t seem like a good idea. So, I went to Thetis Lake instead, a lake few kilometers away from where I leave. There is nothing too exciting in this lake, but at least there were no big waves or kelp. Good conditions to get started.

After about 15 minutes, I was getting used to the controls and was able to go where I wanted in a relatively smooth fashion. The compass, tilt and depth meters on the cockpit display appeared to be essential for navigation. Without these, it would be very easy to get disoriented. The lights are surprisingly powerful and allow to have a good image even at depth where it is very dark. As I expected, there was nothing too crazy to see in the lake. Only a few cans of beer and branches. But at least now I am more comfortable with controlling the Trident.

Next step, the ocean!

​Back in September, I started to investigate how the Trident underwater drone could be useful for our expedition. I quickly realized that it would not only be a nice tool to have, but would be a complete game changer! Its amazing technology and portability would allow us to deploy the hydrophone array without requiring divers. This is huge, because divers can be expensive and the few that have all the required certifications at the University of Victoria are already very busy with other projects. So, with the Trident, I would be able to deploy much more often and at more locations. Also, I could not stop thinking about how neat it would be to integrate hydrophones to it and perform the acoustic localization right from the Trident.

Having limited funding, I contacted OpenROV to see if they would be willing to collaborate and lend us a Trident. I agree… it was a long shot, but I had to try. And I am so glad I did. Nicole Guintu from OpenROV nicely replied to me and told me about the Science Exploration Education (S.E.E.) Initiative. An initiative where OpenROV is giving away 1,000 Tridents to citizens, educators, researchers and students to monitor and protect marine environments. Say no more! I barely finished Nicole’s emails, that I started the grant application process. Unlike typical academic research grants, the application for the S.E.E. initiative is largely based on how the science and progress are communicated to the public. Being the only scientist in my family, I appreciate the importance of science outreach, and could totally relate to this approach. This Open Explorer expedition page is in fact the very product of the application process.

Few days ago, I received the results from our S.E.E. application and…. WE GOT IT!! Our application was successful, and we will receive a Trident in the coming weeks! I can’t think of a better way to end the year. I am really thankful to Madeleine Foote from Open Explorer and the OpenROV team for their support! Also, thanks to all the people who support me by following this expedition and posting comments! Now, just like a kid, I am counting the number of sleeps until the Trident arrives…

It is time to get real and get things wet. The hydrophone and camera array has been sitting in my backyard for few weeks now and it is time to test everything in the ocean!

There are few things I want to know before we start the expedition “for real”. An important one is to see how portable the system is and how easy it is to assemble and deploy it in the field. The goal is to deploy our array at many different places along the coast of British Columbia. So, we need the system to be transportable in a truck or a car and easy to assemble in remote areas. I also want to know if the structure of the array is noisy underwater. If the PVC frame is squeaking whenever there is some current, this would contaminate our measurements and would obviously be a pretty significant issue.

Thanks to my friend John, I got in touch with Ed Wright and Josh Zotzman who work at the Institute of Ocean Sciences in Sidney and were kind enough to let me deploy the array off the Coast Guard dock there. So here we went. Heloise Frouin-Mouy (a bioacoustician at JASCO specialized in pinnipeds, and also my wife as you might have guessed from her name) and Matt Pine (an acoustician colleague at UVic) came along to help me out. The first challenge was to find a way to make everything fit in my car. Let’s say that I don’t really have a big truck, but rather a tiny European-sized car. Nonetheless, after several iterations, we managed to make everything fit! System portability: Check! After a smooth ride to Sidney, we met with Josh and he escorted us to the Coast Guard dock. It took us about an hour to assemble the PVC frame, install the acoustic recorder, and secure the hydrophones and camera. Not bad for a first time! Ease of assembly: Check! Heloise, Josh and I then lowered the array off the dock in about 10 m of water. It took us some time to find out the best way to do this, but at the end it went pretty smoothly. Few things on the frame need to be modified to make the deployment easier, but overall the PVC frame was sturdy enough to handle the deployment. It is always stressful to put all this electronics in the water… Even if I had double checked everything several times, there is always the worry of having forgotten something. Did I close the pressure case of the camera properly? Wait… did I put the waterproof plug back on? Once we left the dock, I just couldn’t stop looking at all the pictures we took and zoom in on every single detail to check that everything was ok. I spent so much time designing and building this array that I really didn’t want to find everything flooded.

We came back the next day to retrieve the instrument and everything worked fine! The camera worked great, so did the acoustic recorder. That was a relief. We even had the privilege to have a small group of harbor porpoise come say hello. I listened to the acoustic recordings and apart from few crabs chomping away at the legs of the structure, the PVC frame did not generate much noise. Quiet frame: check!

This test deployment was successful, and I am very excited to have everything together and working. I am dealing with some administrative/permitting paperwork right now, but very soon this expedition will be underway! We will finally be able to deploy the array off Victoria and start our fish sound cataloging effort. I can’t wait!

​Here is an interview in the CBC Radio show Quirks and Quarks about our research on fish sounds. Disclaimer: I have been tricked into mimicking cat fish sounds... and yes, you can make fun of me ;-)

https://www.cbc.ca/radio/quirks/hearing-plants-awkward-bees-arctic-gems-farting-fish-and-chicken-bones-1.4234437/spying-scientists-listen-in-on-fish-conversations-1.4234447

The first field test of the camera was very beneficial and allowed to identify few issues. So, I spent some time modifying the system so it is more stable and can record for longer periods of time. I also had to design a light PVC frame to hold all the instruments together on the seabed. Something that is easy to assemble, carry and repair in the field. It is now built and is sitting in my backyard which, as you can imagine, attracts the curious neighbors.

Things are coming along and I am hopeful that we will be able to start deploying the system in the water soon !

PS: In the video below you can see a simulated observation of 1 male and 2 juveniles fish swimming beside the hydrophone array ;-)

It was a Tuesday morning when I received that email. I must have misunderstood… It just can’t be right.


Since I started to work in underwater acoustics, I have had the privilege to work with many smart and friendly people. People that influenced not only my career but also my personal life. Callum is one of them. I have met him at the Canadian Healthy Oceans Network conference in Ottawa back in 2017. He was presenting some of the work he was doing for his M.Sc. at Memorial University in Newfoundland. His project was quite interesting. He put together a high definition cinema-grade camera system towed on the seabed to map benthic communities off New Brunswick. He was specifically interested in how the distribution of sea potatoes (Boltenia ovifera) was related to the physical properties of the ocean. If sea potatoes are not your thing, believe me, talk to Callum and he will make them be your new favorite animal! His enthusiasm and passion were contagious. We connected right away. When I explained to him the camera system I was trying to put together I could see sparkles in his eyes. Since that day we started to work together. He brought to me his technical expertise and a wealth of experience on camera systems, and I helped him out with some programming he needed to process his images. He is the one who pointed me towards the 110-degrees camera lens I am using now. He is also the one who introduced me to the Trident ROV. In May 2018, we met again in Montreal for the World Conference on Marine Biodiversity. We even shared a room to keep the travel costs down. He was about to finish his M.Sc., just found a dream job in Newfoundland and was moving soon with his girlfriend.

When I received the email that Tuesday morning with the subject line “Callum Mireault”, I immediately thought that Callum wanted to chat about a script I had just sent him. Then, I read more carefully and realized that the message was not from Callum but from Paul Snelgrove, a professor at Memorial University working with him. I kept reading and re-reading the email trying to find the part that I misunderstood. But no, unfortunately, I understood correctly... Paul was announcing that Callum had a heart attack and passed away. He was not even 30.

Still to this day, I have a very hard time wrapping my head around the loss of Callum. This project would not be where it is now without him. He would certainly have been excited to be part of this expedition.

Building an autonomous video camera system that can record continuously for several days has been challenging. But things are coming together. We finally tested our first prototype in the field. Tristan took the system out to Madrona Point, close to Nanaimo. He and Courtney, his diving partner, dove and placed the camera prototype and an acoustic recorder at a site covered in Yelloweye and Quillback rockfish.

The test was very successful ! The camera worked well and we gathered data that will allow us to improve the system. Very encouraging! Also very excited to report that we recorded our first rockfish sounds!

Photos by Tristan Blaine.

For our expedition, one of the great tools that we plan to use is the Trident Remotely Operated Vehicule (ROV) from OpenROV. This is basically the underwater version of a drone. It "flies" through the water and thanks to its integrated camera, let you see and explore the ocean just like if you were diving. Unlike many ROVs, it is small, very portable and can be controlled from shore or from any type of boats (motor boats, kayaks, etc.). This amazing little instrument will be key for many aspects of our expedition.

Searching for good deployment sites. Once we have selected the general location of our study sites, we need to find the perfect spot to deploy our hydrophone and camera array. It needs to be relatively flat for the structure to be stable and close to fish aggregations, so we can capture their sounds. The Trident will be used before the deployment to identify good locations for the array.

Retrieving the hydrophone array. Deploying the hydrophone array on the ocean floor is easy. We just lower it down from the boat with a line. Once the array is on the bottom, we let go one end of the line and pull on the other end to get it back. To retrieve the array, this is more tricky. We need to find a way to attach the line back to the array. We can't leave a surface float on the array like crab or lobster traps because it would make too much noise that would contaminate our acoustic recordings. So, instead we will use the Trident to hook the line back to the array. Just like the video below. Then, we can pull the array back at the surface from the boat using that line. This retrieval technique is efficient, requires only 2 persons and will allow us to deploy in many places around the BC coast.

Cataloging fish sounds. Many fishes like to hide and hang out in rocks and boulders. Unfortunately, due to its size and shape, our hydrophone and camera array can only be deployed in areas where the bottom is relatively flat. So, we will design a small array of 2 or 3 hydrophones that we will attach to the Trident. These hydrophones combined with the camera from the Trident will allow us to catalog fish sounds in much more complex habitats than with the fixed array. This idea is actually not new. Rodney and Francis have already tried to add hydrophones to ROVs almost 10 years ago (see their paper here). But what they found at the time is that regular ROVs are very noisy and make the recording of fish sounds very challenging. With its much smaller and streamlined design, we are very confident that the Trident won't have that problem.

I am so excited to start playing with this really neat ROV!

​To catalog fish sounds in their environment, we need hydrophones to record sounds and cameras to visually identify the species making them. But what if a fish is making sounds outside the field of view of the camera ? Well, this could be a problem... When we see a fish on the camera, we need to make sure that it is the one making the sounds. This is where the passive acoustic localization comes in.

Imagine yourself in a busy street of a city. Now close you eyes and listen.... The jack hammer across the street from the construction workers, the siren of the ambulance passing by, the bird chirping away above your head, a baby crying in a stroller behind you. Even though you can't see them, you know precisely where all these sounds come from. And all of this is because your ears are few centimeters apart and don't receive the sounds exactly at the same time. Only few microseconds...but this tiny difference is enough for your brain to find out where the sound comes from. For our fish sounds we can use the same principle, except that we use hydrophones instead of our ears and that we are not limited to 2! The more hydrophones you use, the more accurate the localization.

Earlier this year, we published a proof-of-concept paper just showing that. We used data that Rodney had collected several years ago in Cape Cod with 6 hydrophones and a 2 cameras, and were able to localize sounds in 3D and associate them to a fish called the tautog. For our expedition in British Columbia, we will use the same approach. However we can't use the same instruments. The system used in Cape Cod was cabled to a dock and could only record for 2 or 3 hours. For our expedition we need to record for several days at a time and in places that are too far from shore to use cabled instruments. This looks like a detail, but it is actually a fairly big challenge that has kept me busy for some time. Especially for the video camera. There are no video camera systems on the market that can record autonomously for several days (at least at a reasonable price). So, I have been working away on designing a low-cost camera unit based on raspberry Pi computers. First field test to come soon...

Rodney has been studying fish sounds for decades! It is truly a privilege to be able to collaborate with him on this project. Listen to his short introduction to the topic. You can also check out his website.