Underwater sound levels in the Canadian Arctic, 2014-2019.

The Arctic has been a refuge from anthropogenic underwater noise; however, climate change has caused summer sea ice to diminish, allowing for unprecedented access and the potential for increased underwater noise. Baseline underwater sound levels must be quantified to monitor future changes and manage underwater noise in the Arctic. We analyzed 39 passive acoustic datasets collected throughout the Canadian Arctic from 2014 to 2019 using statistical models to examine spatial and temporal trends in daily mean sound pressure levels (SPL) and quantify environmental and anthropogenic drivers of SPL. SPL (50-1000 Hz) ranged from 70 to 127 dB re 1 µPa (median = 91 dB). SPL increased as wind speed increased, but decreased as both ice concentration and air temperature increased, and SPL increased as the number of ships per day increased. This study provides a baseline for underwater sound levels in the Canadian Arctic and fills many geographic gaps on published underwater sound levels.

Where else? Assessing zones of alternate ballast water exchange in the Canadian eastern Arctic.

Mid-ocean ballast water exchange (BWE) is recommended for international vessels to minimize the transfer of nonindigenous species (NIS). When this cannot be accomplished due to safety concerns, alternate ballast water exchange zones (ABWEZ) may be used. A coupled-ice-ocean model with meteorological forcing and particle tracking was used to evaluate the relative risks from BWE along primary shipping routes into Canada's eastern Arctic. Relative risk to receiving habitats from BWE was calculated from the product of likelihood of exposure, likelihood of establishment, and habitat sensitivity to potential NIS. Modelling results indicate that existing ABWEZs in and around Lancaster Sound and Hudson Strait are among the areas of highest relative risk for introductions of NIS via ballast water. The deeper offshore regions of Labrador Sea and Baffin Bay should be considered as alternatives. However, further research is recommended to assess the risks of NIS associated with BWE in the Canadian Arctic.