The ocean is not silent. Before humans began generating underwater noise at industrial scale, the world's oceans were filled with a complex acoustic environment — the clicks and codas of sperm whales, the haunting songs of humpbacks, the high-pitched whistles and chirps of belugas, the infrasonic pulses of blue whales that travel thousands of kilometres through deep ocean channels. These sounds are not incidental to marine life. They are its fabric — the medium through which animals navigate, find food, avoid predators, locate mates and maintain social bonds.
Canada's waters on three coasts support remarkable whale diversity. The Pacific hosts humpbacks, orcas, grey whales, minkes and sperm whales. The Atlantic and Gulf of St. Lawrence support critically endangered North Atlantic right whales, fin whales, blue whales and the St. Lawrence beluga, a genetically distinct population that has been in decline for decades. The Arctic hosts narwhals and bowhead whales, species adapted to life in ice-covered waters in ways that make them among the most sensitive indicators of Arctic change.
The St. Lawrence Beluga: An Acoustic Case Study
The St. Lawrence beluga population has been intensively studied for decades and provides one of the most detailed case studies available of how multiple stressors interact to threaten a marine mammal population. Historically reduced by commercial hunting, then exposed to industrial contamination as the St. Lawrence became one of North America's most heavily industrialised waterways, the population dropped to roughly 1,000 animals — far below the tens of thousands that existed before European contact.
Belugas are extraordinarily vocal — they produce more varied sounds than almost any other cetacean, and early mariners called them "sea canaries." Their vocalisations serve complex social functions within the tight-knit groups that belugas form. Research has shown that shipping noise in the St. Lawrence — from commercial vessels using the Seaway and from recreational boat traffic — is sufficiently intense to mask beluga communication at a population level, effectively reducing the acoustic space available for social interaction and the detection of environmental cues.
Humpback Songs and Their Mysteries
Humpback whale song — produced by males during breeding seasons — is one of the most complex and extensively studied acoustic phenomena in the natural world. Humpback songs are not fixed: they change over time in ways that are transmitted culturally through populations, with new elements spreading across entire ocean basins within a few years. The Pacific humpback populations that feed in Canadian waters during summer months before migrating south to winter breeding grounds in Hawaii and Mexico carry and modify these songs, which can be tracked as signatures of cultural transmission across enormous distances.
Conservation and Acoustic Policy
Canada has developed regulations specifically addressing noise impacts on marine mammals — requirements for vessels to slow down and alter course in areas frequented by right whales and belugas, restrictions on sonar use in certain areas, and acoustic impact assessments as part of offshore development approvals. These measures represent genuine progress from the complete absence of acoustic considerations in marine management twenty years ago. But implementation and enforcement remain challenging, and the cumulative acoustic impact of all shipping, resource extraction and recreational activity in Canadian waters has never been comprehensively assessed.