Beluga Vocalizations Decrease in Response to Vessel Traffic in the Mackenzie River Estuary

William D Halliday,Xavier Mouy,Stephen J Insley,R Casey Hilliard,Lisa L Loseto,Dustin Whalen,Kevin Scharffenberg,Shannon Macphee

doi:10.14430/arctic69294

Abstract

Vessel traffic negatively affects marine mammals by causing behavioural disturbance, acoustic masking, contamination (i.e., oil spills), and ship strikes. Few studies have examined the effects of vessels on marine mammals in the Arctic, but beluga whales appear to be especially sensitive to vessel traffic. We examine how the vocalizations of belugas are impacted by vessel traffic in the Tarium Niryutait Marine Protected Area in the Mackenzie River estuary of the western Canadian Arctic. Between one and four acoustic recorders were deployed between June and August each year between 2015 and 2018 near the only shipping channel at this site. We examined beluga vocalizations from acoustic recordings over four summers and assessed how the distance to the nearest vessel passing the acoustic recorder affected the number of vocalizations. Beluga vocalizations within the range of the acoustic recorder decreased significantly when vessels were within 5 km of the acoustic recorder. This result suggests either that belugas are avoiding the vessel or that they reduce their vocalization in response to vessel traffic. Future work is needed to assess exactly how belugas are reacting to vessel traffic in this area and what the long-term consequences of these reactions are. Management measures for reducing these impacts must be carefully considered, especially since these vessels are very restricted in where they can travel, and many of the vessels are necessary for the livelihoods of local communities.

Highlights

Vessel traffic affects marine mammals in a variety of ways, including behavioural disturbance (Nowacek et al, 2007; Gomez et al, 2016), acoustic masking (Clark et al, 2009; Erbe et al, 2016), chemical contamination (Eide et al, 2007), and strikes (Vanderlaan and Taggart, 2009)
The number of beluga whale vocalizations received at the recorder decreased when vessels were closest to the acoustic recorders in the impact time series (t173 = 2.27, p = 0.02), but remained relatively constant through time in the control time series (p > 0.36; Fig. 3)
We provide evidence that beluga whales showed behavioural responses to vessels in the shallow Mackenzie River estuary based on a decrease in vocalizations in the range of our acoustic recorders

Summary

Introduction

Vessel traffic affects marine mammals in a variety of ways, including behavioural disturbance (Nowacek et al, 2007; Gomez et al, 2016), acoustic masking (Clark et al, 2009; Erbe et al, 2016), chemical contamination (i.e. oil spills) (Eide et al, 2007), and strikes (Vanderlaan and Taggart, 2009) Most of these effects are sub-lethal, but may cause significant impacts on fitness if the animal is exposed to vessels frequently (e.g., Ellison et al, 2016) or in combination with other stressors (National Academies of Sciences, Engineering, and Medicine, 2017). A recent vulnerability analysis of Arctic marine mammals to vessel traffic along the Northwest Passage and Northern Sea Route found that narwhal (Monodon monoceros Linnaeus, 1758), beluga whales (Delphinapterus leucas Pallas, 1776), bowhead whales (Balaena mysticetus Linnaeus, 1758), and walrus (Odobenus rosmarus Linnaeus, 1758) are most vulnerable to increased vessel traffic (Hauser et al, 2018)

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