Vessel noise modelling around the Port of Prince Rupert, British Columbia, and the potential effects on marine mammal listening distance

Underwater sound was modelled around the Port of Prince Rupert, British Columbia. The waters around the port region contain major international shipping lanes and important habitat for marine species, many of which require a quiet environment. Underwater noise calculations were carried out using JASCO's Acoustic Real-Time Exposure Model for In-motion Sources (ARTEMIS), a cumulative noise exposure and noise mapping model. Vessel traffic for three Periods were modelled using Automatic Identification System (AIS) vessel position reports from 2019: 1 to 31 January, 15 Jun to 15 July, and 15 September to 15 October. Vessel source levels were modelled using the JOMOPANS-ECHO reference spectrum model (MacGillivray and de Jong, 2021). Ambient noise was modelled using the Wind and Rain Ambient Sound Propagation (WRASP) model (Ainslie, 2010). Sound propagation loss was precomputed using the normal mode code, ORCA (Westwood et al., 1996). Vessel traffic projections for 2030 were created with AIS data from 2019 and 2020 to simulate underwater sound levels for 2030. Potential effects on marine mammals was assessed by calculating the relative reduction in distance (listening distance ratios) to which they could communicate, forage, and detect predators due to vessel noise. Listening distance ratios were assessed for 2030 using 2019 as a baseline.