Ambient noise and temporal patterns of boat activity in the US Virgin Islands National Park

Abstract

Human activity is contributing increasing noise to marine ecosystems. Recent studies have examined the effects of boat noise on marine fishes, but there is limited understanding of the prevalence of this sound source. This investigation tracks vessel noise on three reefs in the US Virgin Islands National Park over four months in 2013. Ambient noise levels ranged from 106-129 dB rms re 1 µPa (100 Hz -20 kHz). Boat noise occurred in 6-12% of samples. In the presence of boat noise, ambient noise in a low-frequency band (100-1000 Hz) increased by >7 dB above baseline levels and sound levels were significantly higher. The frequency with the most acoustic energy shifted to a significantly lower frequency when boat noise was present during the day.These results indicate the prevalence of boat noise and its overlap with reef organism sound production, raising concern for the communication abilities of these animals.

Temporal trends in cusk eel sound production at a proposed US wind farm site

“…pile driving), wind-driven operation sounds, and the related vessel traffic supporting construction or servicing the turbines. Vessel noise likely contains frequencies that overlap those of cusk eel calls (our data as well as Madsen et al 2006, Bailey et al 2010, Kaplan & Mooney 2015. Turbine operation sounds have the potential to be relatively constant, but they tend to be lower in frequency than cusk eel sounds (Madsen et al 2006, Tougaard et al 2009) and their low source levels suggest a limited range of masking influence.…”

Variation in hearing within a wild population of beluga whales (Delphinapterus leucas)

“…However, the peak fishing period is of relatively short duration, and open fishing times are often intermittent (dependent on rates of fish passage), suggesting that noise exposures and hearing impacts are potentially high amplitude but also short in duration. Further, boat noise tends to have dominant sound levels at lower frequencies (<5 kHz) (Kaplan and Mooney, 2015), less than the frequencies tested in this study, and in a range where belugas are not typically sensitive. Vessel noise has relatively little energy in the ultrasonic frequencies of best hearing for these belugas.…”

Human auditory discrimination of bottlenose dolphin signature whistles masked by noise: Investigating perceptual strategies for anthropogenic noise pollution

“…Further research, ideally using samples of boat noise in a controlled experimental setting, ought to expand upon this phenomenon and determine the role that masking may play in these interactions. Kaplan and Mooney (2015) conducted an acoustic survey of the U.S. Virgin Islands National Park and found boat noise in approximately 6% -12% of their samples. This noise included frequencies which could potentially mask local marine life, and contributed significantly to the total amount of environmental noise when boat noise was present.…”

“…This noise included frequencies which could potentially mask local marine life, and contributed significantly to the total amount of environmental noise when boat noise was present. It was suggested that this amount of boat traffic, combined with its amplitude and frequencies, might impair local species' (including species of dolphins) abilities to communicate and perceive their environments (Kaplan & Mooney, 2015). For species such as dolphins, this could result in impaired foraging ability and potentially force pods of dolphins to seek out locations with less boat traffic, either restricting them to specific parts of the park, or forcing them to leave the park entirely.…”