title: High frequency components of ship noise in shallow water with a discussion of implications for harbor porpoises (Phocoena phocoena).
abstract: Growing ship traffic worldwide has led to increased vessel noise with possible negative impacts on marine life. Most research has focused on low frequency components of ship noise, but for high-frequency specialists, such as the harbor porpoise (Phocoena phocoena), medium-to-high frequency noise components are likely more of a concern. To test for biologically relevant levels of medium-to-high frequency vessel noise, different types of Automatic Identification System located vessels were recorded using a broadband recording system in four heavily ship-trafficked marine habitats in Denmark. Vessel noise from a range of different ship types substantially elevated ambient noise levels across the entire recording band from 0.025 to 160 kHz at ranges between 60 and 1000 m. These ship noise levels are estimated to cause hearing range reduction of >20 dB (at 1 and 10 kHz) from ships passing at distances of 1190 m and >30 dB reduction (at 125 kHz) from ships at distances of 490 m or less. It is concluded that a diverse range of vessels produce substantial noise at high frequencies, where toothed whale hearing is most sensitive, and that vessel noise should be considered over a broad frequency range, when assessing noise effects on porpoises and other small toothed whales.
authors.affiliation: Zoophysiology, Department of Bioscience, Aarhus University, C. F. Moellers Allé 3, 8000 Aarhus C, Denmark.
authors.forename: Line
authors.initials: L
authors.lastname: Hermannsen
authors.affiliation: Zoophysiology, Department of Bioscience, Aarhus University, C. F. Moellers Allé 3, 8000 Aarhus C, Denmark.
authors.forename: Kristian
authors.initials: K
authors.lastname: Beedholm
authors.affiliation: Department of Bioscience, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark.
authors.forename: Jakob
authors.initials: J
authors.lastname: Tougaard
authors.affiliation: Zoophysiology, Department of Bioscience, Aarhus University, C. F. Moellers Allé 3, 8000 Aarhus C, Denmark.
authors.forename: Peter T
authors.initials: PT
authors.lastname: Madsen
mesh_terms: D000162:Acoustics; D000818:Animals; D001309:Auditory Threshold; D003718:Denmark; D004784:Environmental Monitoring / Q000379:methods; D006309:Hearing; D009038:Motion; D009624:Noise, Transportation / Q000009:adverse effects*; D050741:Phocoena / Q000502:physiology* / Q000523:psychology; D018570:Risk Assessment; D012767:Ships; D012815:Signal Processing, Computer-Assisted; D013018:Sound Spectrography; D014867:Water
chemical_list: D014867:Water