First observations of anthropogenic underwater noise in a large multi-use lake

Over the last fifty years, anthropogenic noise has increased dramatically in aquatic environments and is now recognised as a chronic form of pollution in coastal waters. However, this form of pollution has been largely neglected in inland water bodies. To date, very few studies have investigated the noise spectra in freshwater environments and at present no legislation exists to protect freshwater organisms from anthropogenic noise. The present study represents the first assessment of anthropogenic noise pollution in a large multi-use lake by characterising noise levels of the main ferry landings of the lake of Windermere, UK using Passive Acoustic Monitoring (PAM). During November 2014, acoustic samples (10 min long) were collected from such areas using a calibrated omni-directional hydrophone and their spectral content was analysed in 1/3 octave bands (dB re 1 µPa). Results indicate that the current noise levels in Windermere warrant further investigation as a potential threat to the fish community which occurs in this already delicate and pressured habitat. Based on results obtained, it is recommended that further studies focus on a wider geographical and temporal range in order to start to fill the knowledge and legislative gaps regarding anthropogenic noise monitoring in fresh waters.