Underwater Noise and Marine Mammals #clearfacts #underwaternoise #marinemammals


Each day, Canadians benefit from commercial marine shipping. However, these activities which we rely upon for global trade take place across many complex ecosystems that are home to at-risk marine life such as whales.

With increased marine traffic in Canada’s coastal waters comes an increase in underwater noise from vessels – and a need to understand the impacts on marine mammals who use sound to communicate, feed, navigate and reproduce.

This site’s purpose is to share objective information about the impact of underwater noise from marine traffic on marine mammals – in particular on whales – and to encourage informed conversations about the issue.

This site was created by Clear Seas Centre for Responsible Marine Shipping, an independent research centre that supports safe and sustainable marine shipping in Canada.

Marine mammals and underwater noise

Imagine you live in a dark place and you must rely on your hearing the same way you would rely on your vision.

And that space is loud and getting louder.

It’s certain to cause you stress.

Sound is critical to the survival of many marine animals and it is widely recognized that underwater noise has both short-term and long-term impacts on marine life.

How a marine mammal responds to underwater noise is complex and depends on a number of factors including:

  • Age
  • Sex
  • Hearing sensitivity
  • Behavioural state
  • Presence of offspring
  • Proximity to shoreline

Underwater noise can negatively affect marine mammals’ ability to:

  • Find prey
  • Avoid danger
  • Communicate
  • Rest
  • Reproduce
  • Navigate

Underwater noise can negatively affect marine mammals, resulting in:

  • Changed behaviours
  • Hearing loss
  • Increased stress levels
  • Displacement to quieter waters
  • Injury or death

Marine mammals communicate underwater using:

  • Short pulses and whistles
  • Clicks for navigation and social interaction
  • Different vocal dialects for contact
  • Very low frequencies for long distances
  • Special structures in their jawbone for hearing

Underwater noise

Sounds in the ocean come from both natural and human-made sources.

Sound describes the effect a vibrating object has on its surrounding environment. Underwater sound is generated by a variety of natural sources, such as breaking waves, rain, under sea volcanoes, hydrothermal vents and marine life. It is also generated by a number of human-made (anthropogenic) sources, including ships, seismic surveys and sonars.

Primary Sources of Underwater Noise

Natural Sources

Rain - Clear Seas
Storms - Clear Seas
Cracking ice - Clear Seas
Cracking ice
Marine life - Clear Seas
Marine life
Surface waves - Clear Seas
Surface waves
Earthquakes - Clear Seas
Hydrothermal vents - Clear Seas
Hydrothermal vents

Human-made Sources (Anthropogenic Noise)

Commercial vessels - Clear Seas
Commercial vessels
Recreational vessels - Clear Seas
Recreational vessels
Pile driving - Clear Seas
Pile driving
Sonar - Clear Seas
Seismic surveys - Clear Seas
Seismic surveys
Snowmobile on ice - Clear Seas
Snowmobile on ice

How Sound is Measured Underwater

Underwater sounds are measured with hydrophones – devices that produce small electrical signals when subjected to a change in pressure underwater. Typical frequencies associated with underwater sounds are between 10 Hz and 1 MHz. Learn more

Underwater noise from marine shipping

Commercial marine shipping is one of the main sources of human-made underwater sound and shipping’s contributions to underwater noise have been increasing.

Ships and other motorized vessels produce a range of sound frequencies which overlap with the frequencies produced by whales and other marine mammals. Vessel noise is particularly chronic and loud in coastal areas near active shipping lanes, ferry routes and ports. Additionally, sound travels more than four times faster in water than in air.

There are two main sources of noise from ships:

Propellers - Clear Seas


Noise is emitted when the low pressure generated by the propeller causes thousands of tiny bubbles to form. When the bubbles collapse, the sound made is a major source of noise. Known as "cavitation,” it accounts for 80-85% of the noise from a ship.

Machinery - Clear Seas


Diesel engines are a significant source of noise because of the vibrations that radiate through the ship’s hull.

Vessels cause different levels of noise depending on the vessel type, ship design, ship speed, how well the hull and propeller are maintained, and other factors.

Vessel noise and whales

Ships produce noise at frequencies ranging from 20 to 100,000 Hertz. This noise overlaps with the frequencies used by whales and other marine mammals to communicate, feed, navigate and reproduce, reducing the area within which whales can effectively function.

Listen to what it sounds like when a ship passes a pod of orcas

Learn more about three whale populations found in Canada that are endangered and impacted by underwater noise.

Southern Resident Killer Whale – Salish Sea

  • With a population of 76 (as of June 2019) the Southern Resident killer whale species is considered to be endangered and declining. Learn more
  • Southern Resident killer whale habitat overlaps with busy commercial shipping lanes and ferry routes
  • Underwater noise from existing marine traffic in the Salish Sea is disruptive to the Southern Resident killer whale’s ability to hunt, navigate and communicate
  • The Government of Canada has identified underwater noise as one of a number of key threats to the existence of the Southern Resident killer whale
  • Measures are being examined and implemented to reduce or minimize these disturbances (see the Government of Canada’s Whales Initiative: Protecting the Southern Resident Killer Whale and 2019 plan for protecting Southern Resident killer whales)

North Atlantic Right Whale – Atlantic Canada

  • The North Atlantic right whale is considered one of the world’s most endangered whale populations
  • Historically, the species gets its name from the whaling industry as whalers considered them the “right” whale to hunt
  • Today, threatened by ship collisions, entanglements in fishing nets and underwater noise, the right whale population is estimated to be close to 400
  • In 2003, the Government of Canada moved shipping lanes in the Bay of Fundy in an attempt to reduce ship strikes and minimize disturbances in critical habitat
  • In 2017, the Government of Canada instituted seasonal speed restrictions in sections of the Gulf of St. Lawrence in an effort to reduce ship strikes and restrictions on commercial fisheries to reduce whale entanglement. Learn more

Beluga Whale – St. Lawrence Estuary

  • Although belugas are typically found in Arctic waters, the St. Lawrence Estuary is home to the most southern population of these animals - also known as "white whales"
  • Considered to be endangered, the population has undergone a slow decline since the early 2000s and is estimated to have fewer than 890 individuals in 2019
  • A number of factors impact this population including habitat loss, finite food sources and noise disturbances from human activity like boating, whale watching and commercial shipping
  • Belugas, being very vocal animals, are frequently called "canaries of the sea"

Critical habitat of whales overlaps with major shipping routes in Canada

Critical habitat is defined by Fisheries and Oceans Canada as the habitat that is deemed necessary for an at-risk species' survival or recovery. The full range of a species’ habitat is often larger than the critical habitat.

Canadian Map - Clear Seas
Quebec City
Saint John
Southern Resident Killer Whale
St. Lawrence Beluga Whale
North Atlantic Right Whale

Reducing Vessel Noise Impacts

The issue of underwater noise in Canada has been considered for many years and yet, assessing how vessel noise impacts marine mammals and how they can be protected remains very complex.

While there is consensus that underwater noise impacts marine mammals, there are still gaps in our understanding, including how to best mitigate it. For example, how do you determine how much of the sound from vessels reaches animals directly, or how much noise is too much for a given species?

The variables that must be considered are almost limitless – from the salinity, temperature and depth of the water, to the conditions present at the ocean floor to the type of noise. Also, data gathered from one area and one species cannot necessarily be transferred to another location or another species.

Cumulative impacts must also be taken into account. On its own, underwater noise may pose a threat – but what happens when it is combined with other stressors like food shortages or pollution? How do you separate noise from other human pressures on the marine environment?

We still have a lot to learn about the effects of vessel noise on marine mammals, but there are strong indications that it is a significant stressor that could be affecting their chance of survival. And so, we need to take precautions now. – Honourable Marc Garneau, Minister of Transport, May 3, 2017

Ways for vessel owners and operators to reduce ship noise:

Slow down

Operate below the cavitation speed and avoid rapid acceleration


Maintain clean hulls and propellers to reduce cavitation


Alter route when in the immediate vicinity of whales or other marine mammals


Incorporate quieting measures, such as hull design and engine type, when new vessels are built

Initiatives Underway

Currently in Canada, government agencies, universities, industry, Indigenous communities and non-governmental organizations are working to understand underwater noise and its impacts on marine life.

Research projects and initiatives on underwater noise and its impacts on marine life are underway at Canadian institutions, including work at Fisheries and Oceans Canada, Transport Canada, Royal Canadian Navy, Ocean Frontier Institute, Port of Vancouver and the ECHO Program, World Wildlife Fund Canada, Vancouver Aquarium, Wildlife Conservation Society of Canada, and Eastern Charlotte Waterways, among others. A number of these and other initiatives are described here:

National and International

Guidelines for Reducing Underwater Noise from Commercial Ships, International Maritime Organization
  • In 2014, the International Maritime Organization (IMO) adopted guidelines to reduce underwater noise from commercial ships
  • The guidelines provide advice for designing quieter ships and for reducing noise from existing ships
  • The guidelines also advise owners and operators on how to minimize noise through ship operations and maintenance
Quieting Ships to Protect the Marine Environment, Government of Canada and IMO
  • The Government of Canada hosted a multi-day technical workshop at the IMO’s headquarters in London in January 2019
  • The workshop brought together experts and policy makers to assess the benefits and barriers of using new ship designs and leading technologies to reduce underwater noise from ships
Canada’s Oceans Protection Plan
  • As part of the $1.5 billion Oceans Protection Plan announced in November 2016, the Government of Canada offers new protections for whales and a commitment to better understand the cumulative effects of shipping on marine mammals such as Southern Resident killer whales, belugas and North Atlantic right whales, with additional commitments since to support new research
  • Work is underway to establish baselines for underwater noise and options to mitigate those effects
Fisheries Act - Regulations for Approaching Marine Mammals, Fisheries and Oceans Canada
  • The Fisheries Act forbids coming within 100 m of any marine mammal in Canadian waters
  • These regulations prescribe actions to be taken by vessels in the presence of marine mammals, including speed limits, control of echo sounders and minimum distances to keep away ranging from 400 m in certain habitat areas to 50 m in parts of the Churchill estuary depending on the species, its status and location. Details can be found here
Marine Environmental Observation Prediction and Response Network (MEOPAR)

MEOPAR is involved in several projects related to underwater noise, including:

  • NEMES project modeling ship movements to predict the exposure of animals to vessel noise
  • WHaLE project (Whales, Habitat and Listening Experiment) to give better information on whale locations to mariners on the Atlantic and Pacific coasts
  • Building a Marine Mammal and Maritime Traffic Simulator for the St. Lawrence Estuary
Ocean Networks Canada (ONC)
  • Ocean Networks Canada monitors Canada’s coasts to continuously deliver real-time data to support evidence-based decision-making on ocean management, disaster mitigation and environmental protection
  • Ocean Networks Canada’s hydrophones and listening stations listen live and archive sound in the ocean from Vancouver, British Columbia to Cambridge Bay, Nunavut
Performance Indicators for Underwater Noise, Green Marine Environmental Certification Program
  • In 2017, Green Marine introduced two new performance indicators addressing underwater noise emanating from ships and port activities respectively, with the goal of reducing the impact of noise on marine mammals
  • As of 2018, ports and ship owners operating in salt water need to meet the underwater noise indicators’ criteria to earn a Green Marine certification
  • These new indicators are intended to encourage the maritime industry to work in collaboration with the scientific community to collect data on noise emissions that can be used to develop further strategies for noise reduction

Atlantic and Gulf of St. Lawrence

Impacts of Rerouting Marine Traffic in the St. Lawrence Estuary, Government of Canada
  • In 2014, Fisheries and Oceans Canada examined marine traffic exposure of St. Lawrence Estuary belugas under actual and proposed commercial shipping routes to determine effects on this whale population
  • The study found that rerouting marine traffic from the North to South Channel of the St. Lawrence Estuary would increase the vessel noise exposure of the female and juvenile belugas important to the recovery of this endangered species
  • The study recommended that maintaining the major vessel route in the North Channel would minimize impacts on belugas
Tracking Marine Mammals and Vessels in the St. Lawrence, Government of Quebec
  • The Government of Quebec is investing $2.1 million over five years in a program to develop 3D simulator technology to track the movements of marine animals and boats in the St. Lawrence
  • The program is a collaboration between the Université du Québec en Outaouais, Fisheries and Oceans Canada and the Group for Research and Education on Marine Mammals (GREMM)
  • The model is envisioned to assist in evaluating the relative impact of different marine traffic scenarios on belugas and support government decision making to reduce ship strikes and noise pollution in the St. Lawrence
Underwater Listening Stations in the St. Lawrence, Government of Canada
  • In 2018, Fisheries and Oceans Canada installed 10 underwater listening stations (hydrophones) to learn more about the endangered St. Lawrence beluga population and better inform future policy to enhance beluga protection
  • The listening stations will provide data about both ship noise and belugas to identify what levels of noise the belugas are exposed to, in which areas, and for how long
  • The research is expected to continue until 2022
Vessel Slowdown in the Gulf of St. Lawrence, Government of Canada
  • In August 2017, after the death of twelve North Atlantic right whales in Canadian waters, Fisheries and Oceans Canada announced new regulations to protect this endangered species in the Gulf of St. Lawrence
  • In 2018, the mandatory speed restrictions in the western Gulf of St. Lawrence were reinstated from April to November 2018 and no North Atlantic right whales were found dead in Canadian waters in 2018
  • In 2019, the government announced an updated plan, developed with interested stakeholders, to protect endangered North Atlantic right whales while sustaining and growing the ocean economy of eastern Canada
  • The mandatory vessel slowdown when whales are present is reinstated as of April 2019
  • The seasonal mandatory vessel slowdown when whales are present was reinstated from April to November 2019


Government of Canada Measures to Reduce Southern Resident Killer Whale Disturbances
  • On May 10, 2019, the Government of Canada announced a series of protective measures. This included a five-year conservation agreement with leading shipping groups to reduce disturbance to Southern Resident killer whales from large commercial vessels that operate in their habitat and visit the Port of Vancouver.
  • The Canadian Government is also entering into an agreement with the Pacific Whale Watch Association who will refrain from offering Southern Resident killer whale tours and will commit to taking other stewardship actions.
Haro Strait Vessel Slowdown Trial, Enhancing Cetacean Habitat and Observation (ECHO) Program
  • Following a 2016 analysis of regional ocean noise contributors, this trial aims to understand the relationship between vessel speed, underwater noise and the predicted effects on endangered Southern Resident killer whales in an important summer feeding area, using hydrophone data and computer modelling to simulate the effects on whale behaviour
  • The analysis from this trial will help determine implications of slowing vessels down in Southern Resident killer whale habitat
  • Between August and October in 2017, all commercial vessels transiting Haro Strait were asked to slow down to 11 knots
  • Average speeds in this area typically range from 18 knots for container vessels to 13 knots for bulk carriers and the slowdown introduced delays of approximately 30-60 minutes depending on conditions and vessel type
  • In 2018, the trial was refined based on 2017 results to include different speeds for different vessel types, ranging from 12.5 to 15 knots, to optimize noise reduction with dynamic start and end dates to maximize vessel participation and benefits to the whales
  • The optimized speed reductions in 2018 added approximately 9-15 minutes of travel time, depending on vessel type
  • Industry participation in this voluntary trial was 61% in 2017 and 88% in 2018
  • The voluntary ship slowdown area was reintroduced and expanded through Haro Strait and Boundary Pass from June 1 to September 30, 2019, with two-week extensions until October 31 if Southern Resident killer whales are present. Details can be found here.
EcoAction Program, Port of Vancouver
  • Following a study on vessel quieting design, technology and maintenance options conducted by the ECHO Program, the Port of Vancouver introduced noise-reduction measures in 2017 to its EcoAction Program to encourage ships trading in the area to quiet the waters
  • Canada was the first country in the world to provide incentives for quieter ships
  • In 2019, the Port of Vancouver increased the number of eligible underwater noise-reducing options
  • Ships with eligible technology or environmental certification can apply for reduced harbour dues of up to 47 per cent
Green Wave Environmental Incentive Program, Port of Prince Rupert
  • The Green Wave program added criteria for vessels to reduce underwater noise through mechanisms such as environmental programs, classification societies, or technology
  • The Port of Prince Rupert was one of the first ports to implement incentives for quieter vessels through reduced harbour dues
Strait of Juan de Fuca Lateral Displacement Trial, ECHO Program
  • Building on the efforts of the Haro Strait Slowdown Trial, a lateral displacement trial began in 2018 to study how moving vessels away from key Southern Resident killer whale foraging areas would affect underwater noise levels in those areas
  • The trial was proposed with the support and collaboration of Fisheries and Oceans Canada, the US Coast Guard, Indigenous communities, environmental and conservation groups, and Canadian and US marine transportation industry
  • The voluntary trial began in late August and ended in October 2018
  • Between June 17 and October 31, 2019, all tugs and barges transiting the Canadian inshore area of the Strait of Juan de Fuca are requested to move south of known killer whale feeding areas
Whales in our Waters Tutorial, BC Ferries, ECHO Program and Ocean Wise
  • The Whales in our Waters tutorial was designed to help mariners recognize and report local whales and learn best practices for navigating ships in the presence of whales
  • Regional mariners, particularly those operating large vessels such as ferries, cargo ships or tugs, are encouraged to complete the tutorial before the summer season, when many whale species return to the Salish Sea to feed
WhaleReport Alert System, Ocean Wise
  • Following the Mariner’s Guide to Whales, Dolphins, and Porpoises of Western Canada and with funding from the Government of Canada, Ocean Wise developed and deployed a mobile and desktop-based program to alert commercial mariners to the presence of whales
  • This system expands vessel monitoring systems and capabilities to enable commercial ships to avoid whales in real time and was developed in collaboration with the shipping industry, coastal pilots, BC Ferries, and the Ports of Prince Rupert and Vancouver

About Clear Seas

Clear Seas Centre for Responsible Marine Shipping is an independent research centre that supports safe and sustainable marine shipping in Canada.

Clear Seas was established in 2014 after extensive discussions among government, industry, environmental organizations, indigenous peoples and coastal communities revealed a need for impartial information about the Canadian marine shipping industry.

Clear Seas received seed funding in 2015 through equal contributions from the Government of Canada (Transport Canada), the Government of Alberta (Alberta Energy) and the Canadian Association of Petroleum Producers. Our funders saw the need for an independent organization that would be a source of objective information on issues related to marine shipping in Canada.

As an independent research centre, Clear Seas operates at arm’s length from our funders. Our research agenda is defined internally in response to current issues, reviewed by our research advisory committee, and approved by our board of directors.

Our board of directors is composed of scientists, community leaders, engineers and industry executives with decades of experience investigating human, environmental and economic issues related to our oceans, coastlines and waterways.

Our reports and findings are available to the public at clearseas.org/en

Sources & Citations

  1. Council of Canadian Academies. (2017). The Value of Commercial Marine Shipping to Canada.
  2. Hildebrand, J. A. (2005). Impacts of anthropogenic sound. In J. E. Reynolds III, (Ed.), Marine Mammal Research: Conservation Beyond Crisis (pp.101-124). Baltimore: The John Hopkins University Press.
  3. Hildebrand, J. A. (2009). Anthropogenic and natural sources of ambient noise in the ocean. Marine Ecology Progress Series, 395, 5-20.
  4. Sound recordings courtesy of: Rain – Sonatech, Inc.; EarthquakesOcean Networks Canada; Hydrothermal VentsTim Crone; StormsHenry Bass, Roy Arnold and Anthony Atchley; Cracking IceOcean Networks Canada; Marine LifeSheila Patek; Surface Waves – Earth Vibes; Ship Passing Pod of OrcasOrcaLab; Commercial VesselsOrcaLab; Recreational VesselsOcean Networks Canada; Snowmobile on IceOcean Networks Canada; Pile Driving – Orca Sound; SonarOcean Networks Canada; Seismic Experiments – J & A Enterprises, Inc.
  5. Transport Canada. (2017). Understanding Anthropogenic Underwater Noise.
  6. Ross, D. (1976). Mechanics of underwater noise. Pasadena: Pergamon Press.
  7. The International Maritime Organization. (2013). Noise from commercial shipping and its adverse impacts on marine life.
  8. Veirs, S., Veirs, V., and Wood, J. D. (2016). Ship noise extends to frequencies used for echolocation by endangered killer whales. PeerJ. doi: 10.7717/peerj.1657
  9. Lesage, V., Barrette, C., Kingsley, M. C. S., and Sjare, B. (1999). The effect of vessel noise on the vocal behavior of belugas in the St. Lawrence river estuary, Canada. Marine Mammal Science, 15(1), 65-84.
  10. Discovery of Sound in the Sea. (2017). Beluga whale, white whale.
  11. Discovery of Sound in the Sea. (2017). North Atlantic Right Whale.
  12. Orca Network (2017). Southern Resident Orca Community Demographics, Composition of Pods, Births and Deaths since 1998.
  13. Port of Vancouver. (2017). ECHO Program.
  14. Fisheries and Oceans Canada. (2017). Evaluation of the Scientific Evidence to Inform the Probability of Effectiveness of Mitigation Measures in Reducing Shipping-Related Noise Levels Received by Southern Resident Killer Whales.
  15. Fisheries and Oceans Canada. (2017). North Atlantic Right Whale.
  16. Canadian Whale Institute. (2017). Changing Marine Policy to Protect Right Whales.
  17. Fisheries and Oceans Canada. (2017). Beluga Whale (St. Lawrence Estuary population).
  18. Species at Risk Public Registry. (2017). Species Profile.