Sealscarer induce behavioural responses of harbor porpoises (Phocoena phocoena).

Abstract

The construction of several wind parks in the North and Baltic Sea and the associated pile driving could negatively affect the only resident cetacean species, the harbor porpoise. We studied the efficiency of a Lofitech sealscarer that emits pulses at a main frequency of 14 kHz to temporarily deter harbor porpoises during construction periods in order to avoid physical injury. Reactions of harbor porpoises were studied by tracking the animals from a cliff 20 m above sea level using a theodolite. Six trials showed animals immediately disappearing after sealscarer activation of 300–700‐m distance to the porpoise with no animal resurfacing within 1 km. A greater deployment distance of 1.2–2.6 km to the porpoise provoked immediate disappearance of two porpoises; four porpoises showed a clear avoidance reaction and change of swimming direction. Reactions of two animals were unclear and these consequently lost; one individual resumed with its normal behavior. These results show that the sealscarer caused porpoises to leave. However, the use of sealscarers cannot guarantee complete absence of porpoises within areas where noise from windfarm construction can potentially harm them since reactions possibly differ between, for example, individuals and/or motivational states.