Ecological Informatics

Friday, July 10, 2020

Acoustic telemetry is a widely applied technique to track animals in aquatic environments.

This technique relies on animals tagged with acoustic transmitters which emit an acoustic signal with a specific ID. These can be detected by a network of hydrophones that have on average a detection range of 300 m. Besides the ID, these also record the date and time of detection.

Hence, acoustic telemetry leads to presence-data only and is often analysed in that sense.

Nonetheless, when a fish is not detected and therefore resides in a zone between 2 hydrophones, it still provides useful information of its (more sparse) position. Our recent publication in Ecological Informatics entitled ‘Quantifying and reducing epistemic uncertainty of passive acoustic telemetry data from longitudinal aquatic systems’ illustrates that the detections can serve as boundary conditions to delineate the durations that animals spent between hydrophones, rather than being a proxy for the time spent near hydrophones.

Consequently providing a spatial and temporal context to the detections and enabling the quantification of epistemic uncertainty (or systematic uncertainty).

The results revealed a logarithmic relationship between epistemic uncertainty and gate network resolution, which indicates that transferring information from the spatial to the temporal level has a positive effect on the epistemic uncertainty.