Averaging underwater noise levels for environmental assessment of shipping

Nathan D. Merchant, Philippe Blondel, D. Tom Dakin, John Dorocicz

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60 Citations (Scopus)


Rising underwater noise levels from shipping have raised concerns regarding chronic impacts to marine fauna. However, there is a lack of consensus over how to average local shipping noise levels for environmental impact assessment. This paper addresses this issue using 110 days of continuous data recorded in the Strait of Georgia, Canada. Probability densities of ∼107 1-s samples in selected 1/3 octave bands were approximately stationary across one-month subsamples. Median and mode levels varied with averaging time. Mean sound pressure levels averaged in linear space, though susceptible to strong bias from outliers, are most relevant to cumulative impact assessment metrics.
Original languageEnglish
JournalJournal of the Acoustical Society of America
Issue number4
Publication statusPublished - 19 Sep 2012

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