Environmental Noise Levels Affect the Activity Budget of the Florida Manatee

TitleEnvironmental Noise Levels Affect the Activity Budget of the Florida Manatee
Publication TypeJournal Abstract
AuthorsMiksis-Olds, J, Donaghay, PL, Miller, JH, Tyack, PL
JournalJournal of the Acoustical Society of America
KeywordsActivity Budget, Environmental Noise, Florida Manatee

Manatees inhabit coastal bays, lagoons, and estuaries because they are dependent on the aquatic vegetation that grows in shallow waters. Food requirements force manatees to occupy the same areas in which human activities are the greatest. Noise produced from human activities has the potential to affect these animals by eliciting responses ranging from mild behavioral changes to extreme aversion. This study quantifies the behavioral responses of manatees to both changing levels of ambient noise and transient noise sources. Results indicate that elevated environmental noise levels do affect the overall activity budget of this species. The proportion of time manatees spend feeding, milling, and traveling in critical habitats changed as a function of noise level. More time was spent in the directed, goal‐oriented behaviors of feeding and traveling, while less time was spent milling when noise levels were highest. The animals also responded to the transient noise of approaching vessels with changes in behavioral state and movements out of the geographical area. This suggests that manatees detect and respond to changes in environmental noise levels. Whether these changes legally constitute harassment and produce biologically significant effects need to be addressed with hypothesis‐driven experiments and long‐term monitoring.

Refereed DesignationUnknown