Hydrophones are microphones designed for use underwater. Hydrophones allow us to listen in to all of the action underwater in a way that is fresh and exciting for most people.
Some hydrophone recording samples:
Winter afternoon in small dam in Googong, NSW.
There is a surprising amount of sound in this small dam. Freshwater Ecologist John Gooderham from The Waterbug Company Pty Ltd has identified the main sound to be Micronecta CORIXIDAE (a small waterboatman). These bugs are quite amazing, and make their sound by stridulating. For details of what that means, check out this article from BBC Nature.
Winter evening in Burrill Lake, NSW, Australia.
You can hear shrimp and shellfish clicking away.