discussion / Acoustics  / 16 November 2023

Hydromoth for coastal & offshore surveying

Hi all! I'm interested in deploying a Hydromoth on an Uncrewed Surface Vehicle (USV) to collect acoustic data for biodiversity analysis, for coastal and offshore marine surveys. We're especially interested in surveying around seagrass beds.

1. Has anyone tried this on a moving vehicle, and had to filter out the noise of motors? The vehicle is electric, but will be producing sound nonetheless.

2. How are the databases for marine wildlife vocalisations in the UK currently?

I'm very interested in adding this to the sensors we plan to deploy so if you have any info, I'm all ears!



Hi Sol,

I think your concern is well placed.  The pros typically tow an array of hydrophones, in its simpler configuration it looks like a long fat rubber hose containing maybe a dozen transducers feeding their electrical signals to a recording unit back on the ship.  All this is done to reduce noise from the ship, from waves crashing, and flow noise.  The multiple transducers can also be electronically tuned to be directional so that it can be "pointed" away from a noise source (like the ship).

In your position, I would just try the simplest thing that could work, then fix the problems as they arise.  It could be you may need to be dead in the water while recording.  To address surface noise (slapping waves, wind), you could mount the hydromoth low down on a spar buoy, which you tow into position.


Best of luck, it sounds like an interesting project (c: