Passive acoustic monitoring (PAM): hydrophone networks

Listening to the ocean around the clock

From the former military SOSUS network to the modern OOI and SAMBAH, autonomous hydrophones now monitor the ocean 24 hours a day. This database presents the main passive acoustic monitoring networks and their results.

Going further

Passive listening complements other approaches: acoustic profile, vocal library, tracking technologies and citizen science.

PAM: cetology through the ear of the hydrophone

Passive acoustic monitoring, or PAM, consists of listening to the oceans with fixed or drifting hydrophones in order to detect, identify and locate cetaceans without disturbing them. The historical network is SOSUS (Sound Surveillance System), run by the US Navy, designed for anti-submarine warfare and opened to scientists after the Cold War.

Today, SAMBAH in the Baltic monitors the harbour porpoise; CETIROISE in the Iroise Sea documents odontocetes all year round; the Scripps HARPs (High-frequency Acoustic Recording Packages) cover the Pacific. The free software tools PAMGuard and Project CETI (Cetacean Translation Initiative, launched in 2020 and run in Dominica) are now attempting to decode sperm whale codas using artificial intelligence.