An important focus of monitoring harbour porpoises for research and construction projects in marine areas is on distribution patterns and reactions of harbour porpoises towards noise-intensive construction measures. But how exactly are these animals, which spend a major part of their lives below the sea surface, monitored?
To achieve this, BioConsult SH uses so-called PODs in addition to aerial and ship-based surveys. The abbreviation stands for Porpoise Detector. These are instruments containing a battery-powered hydrophone and a storage device to record echolocation sounds of harbour porpoises (and other toothed whales). They are able to detect the presence of whales within a radius of up to about 100 m. The approximately 90 cm long devices are deployed in the study area and firmly fixed at a depth of between 5 and 40 metres. After 4 to 6 weeks, the PODs are retrieved and long-term data can be downloaded and evaluated.
PODs are used worldwide. BioConsult SH deployed the first of these devices in July 2008. Eleven years later, our devices have been deployed more than 4000 times in the North and Baltic Seas for many different projects. In March 2019 alone, 101 PODs maintained by BioConsult SH were in use simultaneously. Every year, about 100 GBs of data are recorded. Together with data of aerial and ship-based counts as well as HiDef surveys these data are the basis for environmental impact assessments and research reports.