Changes in fin whale songs are associated with low-frequency noise

Shipping noise can negatively affect baleen whales behaviour, including their reproductive singing. Currently limited research studies have focused on the fin whale (Balaenoptera physalus). By investigating potential associations with increasing low-frequency noise, this study examines whether song features vary with locally recorded noise levels. Background noise levels for 42 songs were measured and analysed in relation to parameters that describe song structure. Here we show that increasing noise levels were associated with significant changes in the inter-pulse-interval, minimum, maximum, peak, center frequency and bandwidth of both classic and backbeat notes, as well as pulse rate. Effects were not the same for all sample sites, suggesting that fin whale responses might depend on seasons, locations and/or inter-individual variability. These findings provide quantitative evidence that local low-frequency noise is associated with variation in fin whale song characteristics, highlighting the need for future studies to determine whether these associations ultimately influence communication efficiency and reproductive performance.