Commercial shipping noise impacts on the critical habitat of the southern resident killer whale (Orcinus orca) Crystal, Danica; Moseley, Kristina; Paterson, Cassandra; Ryvola, Rebeka; Wang, Shasha
Southern resident killer whales (SRKWs), found commonly on the south coast of British Columbia, are an endangered species struggling to maintain its population size. The critical habitat of the SRKW, an area important to the recovery of the species, is also an area traversed by commercial ships on a daily basis. Among other challenges to the whales such as habitat destruction and contamination, noise pollution produced by these commercial ships is one of the threats preventing the recovery of the SRKWs, through masking of whale communications. Masking, the interruption of killer whale vocalizations by background noise produced by ships, reduces group cohesion and forces the whales to spend more time and energy foraging, ultimately decreasing their ability to reproduce and sustain their population. The Canadian Federal Court recently established that protection of this endangered species, managed by the Department of Fisheries and Oceans (DFO), must take into account the impact of noise pollution on the whales, a factor that has not yet been considered. With an expected increase in commercial shipping to BC facilitated by expansions at two ports, there is potential for further threats to the SRKWs through masking of vocalizations. The purpose of this study is to examine the current masking sounds created by commercial ships in the critical habitat of the SRKW and to determine whether imposing speed limits on ships can reduce the amount of masking that occurs. The objectives of this study are to: 1. Identify the areas on the south coast of BC where ships have the potential to mask the SRKW vocalizations when the whales are inshore (May through October). 2. Determine the frequency of masking within these areas. 3. Model speed limit scenarios imposed on ships and assess the effectiveness of these limits at reducing masking sounds. 4. Recommend further research that will contribute to minimizing the effect of ship noise on this endangered population.
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