Acoustic research on porpoises in the Eastern Scheldt

In this pilot project, we are investigating whether it is possible to tell from the sound of porpoises whether we are dealing with a young or an adult animal.

Underwater microphones (hydrophones) are regularly used to monitor cetaceans. The local Dutch cetacean, the harbour porpoise, uses echolocation and produces very specific high-pitched sounds (clicks) to navigate, hunt and communicate. In general, different behaviour can be associated with certain click frequencies. For example, the number of clicks increases rapidly when animals approach their prey. Also, click production depends on the size of the animal, and click sounds are thought to differ between adults and calves.

Impact of human activities

Stationary hydrophones provide information on when porpoises are in the area by recording their clicks. This is particularly useful for determining the impact of potentially damaging human activities, such as the (pile-driving) noise emitted during the construction of wind farms. However, for effective conservation of the species, it is necessary to further investigate the disturbance of specific porpoise behaviours during vulnerable life stages, such as during the presence of calves. For this, it is necessary to know whether one is dealing with a calf or an adult animal when making a sound recording. Within this pilot study, we are looking into whether and how such a thing would be possible.

Within this project, in collaboration with the Rugvin Foundation, an attempt will be made to collect clicks from calves on the Eastern Scheldt and to analyse them. In addition, existing data from calves in captivity (for example from Denmark) will be examined. The team will examine whether the presence of calves can be determined on the basis of the clicks, in order to eventually develop and/or improve an algorithm that can be applied to existing databases.

- Unfortunately, your cookie settings do not allow videos to be displayed. - check your settings

- Unfortunately, your cookie settings do not allow videos to be displayed. - check your settings