Support for marine mammal bioacoustic work


My thesis work involves the use of autonomous recording hydrophones, that are deployed for several months at a time.I would like to use the OpenROV to aid in the deployment and recovery of the hydrophones.

The cheapest and easiest way to deploy the hydrophones it to use anchors and floats, and attach the hydrophone along the line at the appropriate depth, but these sorts of installations often have problems with theft, vandalism and getting tangled with ships. More expensive options are moor them with subsurface floats, and use either divers to service shallow installations, or acoustic releases to release from the anchor and send the float to the surface when a signal is sent. Neither of these options are cheap,

With an ROV, I would be able to do a deployment with no surface float, and have the ROV go down and either cut the anchor line, or attach a retrieval line from the boat. Many users of acoustic releases have an ROV standing by to go down and cut lines when the release fails. With the OpenROV costing 1/2 the price of the cheapest acoustic release (not to mention the cost of the transceiver to send the release code), it could prove to be a great money saver. Even compared to divers, it wouldn't take long for the ROV to pay for itself.

With hydrophones mounted on the ROV, can be combined with the images from the camera to determine pressure levels used in echolocation, and capture behaviors related to the sounds.

Of course, it's also a really cool toy, and would be fun to play with.


Hi David,

I am a PhD student at the University of Victoria in Canada and I am also considering using the Trident to retrieve passive acoustic moorings deployed in shallow water. I was wondering if you had any success with this ?

Xavier Mouy


With regard to retrieving things left on the seafloor, I recently made a post about a line-threading mechanism that can be used to put a line around an object with Trident. Perhaps that would be helpful for your work! I’d love to learn more about your project- it sounds amazing!


Hi Eric. Thanks for your reply. I actually have seen your post and it looks exactly like what I need. Unfortunately, I have not found funding for purchasing a Trident yet (I keep looking though).

My project aims at using passive acoustics for monitoring fish). I am using a compact hydrophone and camera array to localize fish in 3D and catalog their sounds. The Trident is very appealing to me because it would allow me to 1) find good deployment spots, 2) calibrate the acoustic localization on site by mounting a little acoustic transducer on it, and 3) retrieve the unit without divers or acoustic releases (using a system like the one you presented in your recent post). I also think it could be a good platform to mount a couple of hydrophones and perform the sound localization (at least bearing estimate) “live” along with the video stream (using a SBC such as a the raspberry pi).

Anyway, I can see a lot of potential for acoustics research. I just need to find the funding now :wink: