Mapping and Modelling Cumulative Vessel Noise in the Salish Sea
Presentation Abstract
Commercial shipping routes in the Salish Sea pass through important habitat of a number of marine mammal species, including areas used by endangered Southern Resident Killer Whales. Cumulative noise from shipping traffic can reduce distances over which marine mammals can effectively use sound for communicating and foraging. It may also cause marine mammals to change their normal behaviours, or to avoid areas where they would otherwise be present. Mitigating the effects of underwater noise first requires an understanding of the spatial and temporal distributions of vessel noise relative to marine mammal habitat. JASCO developed a model to calculate cumulative shipping noise levels in the Salish Sea on daily and monthly time scales based on historical vessel tracking data from the Vessel Traffic Operations and Support System (VTOSS). VTOSS is based primarily upon radar and automatic identification system (AIS) vessel tracking methods. Sound propagation was computed using spatially- and seasonally-dependent environmental parameters. The sound propagation model was validated with controlled-source acoustic transmission loss measurements in the study area. Acoustic source levels for different categories of vessels were obtained from an extensive commercial vessel traffic noise dataset acquired near the Lime Kiln lighthouse in Haro Strait, and these were supplemented with dedicated measurements and with published ship noise reports. Inter-seasonal variations were addressed by considering month-long and day-periods in both winter (January) and summer (July). The outputs of the cumulative noise model consist of maps of monthly-average noise levels and daily simulations of 1-minute noise levels during a 24-hour period.
Session Title
Understanding and managing potential cumulative threats to marine mammals and their habitats from commercial vessel activities
Conference Track
Species and Food Webs
Conference Name
Salish Sea Ecosystem Conference (2016 : Vancouver, B.C.)
Document Type
Event
Start Date
2016 12:00 AM
End Date
2016 12:00 AM
Location
2016SSEC
Type of Presentation
Oral
Genre/Form
conference proceedings; presentations (communicative events)
Contributing Repository
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Subjects – Topical (LCSH)
Ships--Salish Sea (B.C. and Wash.)--Noise; Marine mammals-Effect of noise on--Salish Sea (B.C. and Wash.); Environmental impact analysis--Salish Sea (B.C. and Wash.)
Geographic Coverage
Salish Sea (B.C. and Wash.)
Rights
This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.
Type
Text
Language
English
Format
application/pdf
Mapping and Modelling Cumulative Vessel Noise in the Salish Sea
2016SSEC
Commercial shipping routes in the Salish Sea pass through important habitat of a number of marine mammal species, including areas used by endangered Southern Resident Killer Whales. Cumulative noise from shipping traffic can reduce distances over which marine mammals can effectively use sound for communicating and foraging. It may also cause marine mammals to change their normal behaviours, or to avoid areas where they would otherwise be present. Mitigating the effects of underwater noise first requires an understanding of the spatial and temporal distributions of vessel noise relative to marine mammal habitat. JASCO developed a model to calculate cumulative shipping noise levels in the Salish Sea on daily and monthly time scales based on historical vessel tracking data from the Vessel Traffic Operations and Support System (VTOSS). VTOSS is based primarily upon radar and automatic identification system (AIS) vessel tracking methods. Sound propagation was computed using spatially- and seasonally-dependent environmental parameters. The sound propagation model was validated with controlled-source acoustic transmission loss measurements in the study area. Acoustic source levels for different categories of vessels were obtained from an extensive commercial vessel traffic noise dataset acquired near the Lime Kiln lighthouse in Haro Strait, and these were supplemented with dedicated measurements and with published ship noise reports. Inter-seasonal variations were addressed by considering month-long and day-periods in both winter (January) and summer (July). The outputs of the cumulative noise model consist of maps of monthly-average noise levels and daily simulations of 1-minute noise levels during a 24-hour period.
