| dc.description.abstract | Anthropogenic noise is a recognised pollutant in both terrestrial and aquatic environments. Noise levels in the ocean have risen greatly over the past few decades. The principal low-frequency background noise in the oceans is generated by commercial shipping, and can have a profound impact on fitness in a variety of marine species. Additionally, the loud impulsive noise from industrial pile-driving activity is increasingly prevalent in the oceans due to the recent development of offshore windfarms to meet renewable energy targets. Little research has explored the impact that this noise is having on marine species, especially invertebrates. The aim of this thesis is to explore the physiological and behavioural responses of marine species to playback of pile-driving noise, using playback of ambient marine sound as a control. The first study aimed to assess the physiological and behavioural response of the decapod crustacean Carcinus maenas to pile-driving noise playback in experimental tanks. In the physiological experiment, crabs did not significantly differ in their oxygen consumption or haemolymph parameters in response to pile-driving noise and ambient sound. However, in the behavioural feeding experiment, crab behaviour was significantly altered during pile-driving playback, including increased time spent immobile and decreased likelihood to feed. The second study aimed to assess the avoidance behavioural response of marine fish in their natural environment to pile-driving noise playback by use of a baited remote underwater video (BRUV) system coupled with a loudspeaker. Playback of pile-driving noise had a significant effect on the number of pelagic fish species surrounding the BRUV, indicating an avoidance effect. However, playback did not have a significant effect on the number of benthic fish species or species richness. Both these studies demonstrate that pile-driving noise causes behavioural changes in marine species, which could have potential fitness costs. Thus, exploration into ways of mitigating noise impacts when undertaking pile-driving activities in the ocean should be further explored. | en_GB |
