01697474

Component

The International Maritime Organization’s Marine Environment Protection Committee recognizes that underwater noise from commercial ships may have short- and long-term impacts on marine mammals. This study assesses the effectiveness of mitigation strategies designed to reduce exposures of marine fauna to vessel noise in the southern Salish Sea. The main shipping routes pass through critical habitat of endangered Southern Resident Killer Whales; a species that uses sound extensively for communicating and foraging. Their biologically-important sounds will be increasingly masked if vessel noise rises. The assessed noise mitigations include slowing vessels, restricting traffic during certain times of the day, rerouting traffic, and convoying commercial vessels. Acoustic models were applied to calculate baseline noise conditions and future noise conditions associated with an increase in traffic from the Trans Mountain project, including the application of mitigation strategies. Vessel noise emission levels for several vessel classes in 1/3 octave bands and their speed dependencies were derived from a large high-resolution vessel noise database obtained from the Vancouver Fraser Port Authority’s Enhancing Cetacean Habitat Observations program. Vessel baseline densities and speeds for 12 vessel classes were derived from Automatic Identification System vessel tracking data for July 2015. Simulated future vessel density, speed and movement changes were prepared for each mitigation strategy. Their effectiveness was evaluated by sampling differences between the future mitigated and baseline noise fields area-wide and at key receiver sites. Some mitigation strategies were found to reduce noise exposures even with increased future vessel traffic, while others were less effective and predicted noise increases.

This paper was sponsored by TRB committee AW030 Standing Committee on Marine Environment.

19-02867

English

12p

2019

Transportation Research Board 98th Annual Meeting

Digital/other

Figures; Maps; References

Environmental protection; Habitat (Ecology); Noise; Ships; Water traffic

Salish Sea

Environment; Marine Transportation; Vehicles and Equipment

Transportation Research Board Annual Meeting 2019 Paper #19-02867

TRIS, TRB, ATRI

Dec 7 2018 9:28AM