Behavioural responses by marine fishes and macroinvertebrates to underwater noise

Roberts, Louise

Abstract

The aim of this thesis was to explore and evaluate the key behavioural responses of coastal UK marine fishes and macroinvertebrates to anthropogenic noise. Work focussed upon two key aspects, water-borne acoustics and the relatively unstudied substrate-borne vibration, with a combination of laboratory and field work using grouped and solitary individuals. A literature review on underwater vibroacoustics, detection abilities, anthropogenic noise sources and the effects of such stimuli was provided (Chapter 1).

Playbacks were undertaken in the field using a purpose-built underwater transducer array capable of accurately reproducing man-made signatures (Chapter 2 – 3). The behavioural responses of wild, unrestrained schooling pelagic fish to impulsive sound were observed using an acoustic observation system. Precise exposure levels were linked to specific responses, with dose response curves produced for two pelagic species of varied hearing abilities. Baited remote underwater video (BRUV) was used to observe the behavioural responses of free-ranging individual fish and crustaceans exposed to impulsive sound and shipping noise. In both cases responses varied according to the level of sound, the type of school and the species.

In the laboratory, animals were exposed to sinusoidal vibratory signals using a fully calibrated electromagnetic shaker system. The sensitivity of unconditioned invertebrates (crustaceans and molluscs) to substrate-borne vibration was quantified with controlled vibratory exposures, allowing the production of a sensory threshold curve for three species (Chapters 4 - 5). Response variation was described in terms of two behavioural indicators, and related to consistency within individuals (personality), morphological parameters and time in the laboratory prior to tests. Further work investigated the response of sessile invertebrates to vibration, with the observations fully described in terms of response occurrence, duration and variation for both grouped and solitary animals.

The responses described in each chapter were related to actual measurements of anthropogenic noise sources in terms of water-borne and substrate-borne energy, allowing behavioural responses to be translated to actual conditions. The data here provide evidence for the levels of playback sound to induce a behavioural response, and are fully reproducible to allow further testing of the responsiveness of fish to different sound levels and signatures. Furthermore, the data are a first step towards understanding the sensitivity of benthic invertebrates to substrate-borne vibration and indicate that the effects of substrate transmission should not be overlooked when investigating the effects of noise pollution on the marine environment. The results from the current work, along with the recommendations for future work, will be important to aid the filling of the ‘information gaps’ that exist within the underwater bioacoustics field.

Citation

Roberts, L. (2015). Behavioural responses by marine fishes and macroinvertebrates to underwater noise. (Thesis). University of Hull. Retrieved from https://hull-repository.worktribe.com/output/4217006

• Thesis Type: Thesis
• Deposit Date: Sep 7, 2015
• Publicly Available Date: Feb 23, 2023
• Keywords: Biological sciences
• Public URL: https://hull-repository.worktribe.com/output/4217006
• Additional Information: Department of Biological Sciences, The University of Hull
• Award Date: Jan 1, 2015