Ranking vessel noise emissions using measurements from an underwater listening station

Abstract

Commercial shipping routes pass through important habitat areas for several species of marine mammals in the coastal waterways of southern British Columbia. The Vancouver Fraser Port Authority, through its Enhancing Cetacean Habitat and Observation (ECHO) program, has undertaken studies to develop mitigation measures that will lead to a quantifiable reduction in threats to whales resulting from shipping activities. This includes long-term measurements of vessel noise at a cabled underwater listening station in Georgia Strait (the ECHO ULS) where JASCO, in partnership with Ocean Networks Canada, has been measuring source levels of vessels calling at the Port using JASCO's PortListen® software. PortListen® receives and processes real-time acoustic and AIS data to calculate vessel source levels using ANSI standard methods (S12.64-2009 R2014). Since September 2015, PortListen® has collected a database of thousands of source level measurements, which has been used to implement ranking system for vessel noise emissions. The ranking system uses a data-driven model to adjust the ranking of each measurement according to the vessel characteristics (e.g., size, class) and measurement conditions (e.g., speed, wind, and draft). In addition to an unweighted noise ranking, the system also provides weighted rankings for five marine mammals hearing groups using NOAA (2016) auditory weighting curves.