Date of Award

10-30-2020

Publication Type

Master Thesis

Degree Name

M.Sc.

Department

Biological Sciences

Keywords

anthropogenic noise, bioacoustics, community effects, fish behaviour, habituation, sensory ecology

Supervisor

Dennis M. Higgs

Rights

info:eu-repo/semantics/embargoedAccess

Abstract

Anthropogenic noise is globally increasing in aquatic ecosystems and causes adverse repercussions in many fish species, yet its effects in the field are not well understood. Here, I test the impact of boat noise on a number of wild freshwater and marine fish species as well as captive black bullhead (Ameiurus melas), a common species in the Laurentian Great Lakes with known hearing specializations. In a laboratory setting, black bullhead were exposed to boat noise, and a quiet control then monitored for changes in foraging behaviours and swimming patterns when presented with food. Black bullhead exposed to boat noise foraged less and startled more in comparison to trials without noise. Similarly, I exposed wild communities to boat noise and a quiet control in the field, then analysed videos for changes in both presence and foraging behaviours. Freshwater field experiments were consistent with results from the laboratory, showing fewer wild fish and foraging attempts during boat noise exposure. Marine experiments also yielded decreases in fish presence during boat noise, however there were no significant changes in foraging behaviours, and fish with previous boat noise exposure did not exhibit changes in behaviours. The effects of noise were highly variable by family though, with sensitive hearing freshwater fish in the Cyprinidae (or Leuciscidae) family predictably exhibiting significantly larger decreases in feeding events and presence compared to other families with more basic hearing abilities. While families in marine environments did exhibit varying degrees of responsiveness, they did not follow the predicted pattern based on hearing abilities. Therefore, while I did find evidence for anthropogenic effects on fish, the degree of impacts is dependent both on species differences as well as the degree of prior exposure, making clear the need for continued research to properly create sound exposure guidelines for conservation.

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