LifeWatch Belgium Cetacean Passive Acoustic Monitoring Network, contribution by MARECO

Presence and activity of harbour porpoises at specific locations is measured by passive acoustic monitoring using hydrophones (C-PODs) (Chelonia Inc). C-PODs can detect odontocete whale, dolphin, and porpoise clicks within a frequency range of 20 – 160 kHz continuously up to at least 300 metres away. They are durable pieces of equipment and can be used in many different environments. Rather than recording audio files, C-PODs collect and store information on the tonal clicks that they detect. This significantly lengthens their battery life and allows them to be particularly useful for long-term studies. Once the C-POD detects a click, it can record the time, centre frequency, sound pressure level, duration and bandwidth of each click that is produced.