Characterization of the underwater noise produced by recreational and small fishing boats (<14 m) in the shallow-water of the Cres-Lošinj Natura 2000 SCI

Underwater Sound Propagation From a Source Close to a Wavy Free Surface

“…This effect is well understood and has been offered as an explanation for why whales and other mammals sometimes fail to detect approaching ships 1 . The effect becomes more pronounced as the source moves closer to the free surface, and so is particularly prominent for small vessels with shallow draughts 2,3 . However, few studies have considered how this is altered by free surface waves.…”

Small Craft Noise: Influence of Speed and Running Attitude on Radiated Noise Levels

“…However, for small vessels the picture is more nuanced, and some studies have shown that small craft can be noisier at lower speeds due to nonlinear changes in engine and propeller loading, and running attitude across their speed profiles. Firstly, despite their reduced size, these smaller vessels do not necessarily produce less underwater noise (source levels in excess of 170 dB re 1 µ m are reported) 4 and such vessels could be more likely to come into contact with wildlife in rich, biodiverse coastal waters 5 .…”

The Acoustic Repertoire of Bottlenose Dolphins (Tursiops truncatus) in the Cres-Lošinj Archipelago (Croatia): Site Dependent Diel and Seasonal Changes

“…Commercial shipping was generally found to increase underwater noise levels over the low-frequency range; however, the contribution of small recreational boats to the higher frequencies may also be substantial as indicated by [8,9]. Since most of the bottlenose dolphin distribution overlaps with coastal waters, the populations are generally exposed to substantial human pressure related to coastal development, ports, and boat traffic [10][11][12]. The underwater noise generated by diverse human activities has been proven to adversely affect the bottlenose dolphins.…”