Vessel Disturbance

Cetaceans live in a noisy world.

Vessel traffic, both commercial and recreational, has increased significantly along the British Columbia Coast. This rise in vessl traffic has caused an increase in physical and acoustic disturbance in cetacean habitat.

Whale watchers not following the Be Whale Wise guidelines (photo credit: Doug Sandilands).
How do vessels disturb whales?
  • Interruption of natural behaviours Disturbance by large and small vessels may disturb and alter activities that are crucial for survival such as foraging, feeding, socializing and breeding. For example, when vessels are nearby, both northern and southern killer whales reduce the time spent foraging in favour of traveling5,11. The interruption of feeding may impact the energy intake of these animals, which if persistent over time, may have individual and population-level impacts.  Southern resident killer whales also exhibit more energy-intensive surface active behaviours (spy hops, breaches, tail slaps, pectoral fin slaps) when vessels are within 200m8. Large whales can also be disturbed.  In Glacier Bay Alaska, humpback whales displayed avoidance behaviours such as diving, swimming away, reducing surface time, and changing respiration rates in the presence of cruiseships7.  


  • NoiseMotorized vessels contribute to underwater noise that can reduce the ability of whales to detect their prey, navigate, communicate, rest and avoid danger.  In high vessel traffic areas, whale communication and echolocation can be almost completely masked by noise1.   Vessel noise can also cause stress in cetaceans and may result in the avoidance of noisy areas3.  Learn more about the effect of noise on cetaceans here.


  • High levels of boat exhaust and emissions.    Like cars, vessels using gas or diesel create exhaust, which can be harmful when inhaled. In particular, marine engines burning diesel contribute significant amounts of sulphur dioxide (SO2), particular matter (PM2.5) and nitrogen oxides (NOx) in B.C.9 Whales are particularly vulnerable to emissions as, unlike terrestrial mammals, they do not have sinuses to filter air and they have no sense of smell to help them detect, and possibly avoid, engine exhaust. Whales also spend much of their time diving, which increases pressure in their lungs and causes air pollutants to enter their blood more rapidly than for non-diving animals.  While studies have shown that current whale- watching guidelines are usually effective in limiting pollutant exposure, during some summertime weather conditions, a build-up of air pollutants caused by the formation of a stable atmospheric inversion layer over the ocean traps air pollutants at the surface where the whales breathe4.


  • Cumulative effect. Vessel disturbance is a cumulative issue. Although one boat may have a small effect, numerous boats and chronic exposure to vessels can lead to significant disturbance of cetaceans. Increased marine traffic around whales has been particularly dramatic in the trans-boundary region of Haro Strait (near Victoria), where a plethora of recreational boaters, both Canadian and American whale-watching boats, and heavy shipping traffic all converge in critical habitat for endangered southern resident killer whales. Data collected by Straitwatch, an on-the-water monitoring group, indicate that southern resident killer whales experience approximately 100 incidents of non-compliance with the guidelines per day from May to September10.  While longer-term studies are required to understand the effect of vessel disturbance on cetaceans in B.C., in Shark Bay, Australia, short-term responses to disturbance has resulted in a decline in abundance of bottlenose dolphins6.  It is also important to note that kayak and other self-propelled vessels can also disturb animals, especially in heavily-used recreational areas12.


The impacts of vessel disturbance also compound other threats. Disturbance causes stress on the animals, exacerbating the impacts of high contaminant loads and decreased food supply.


Kayakers must follow the Be Whale Guidelines too, and always stay on the offshore side of the whales when they are traveling close to shore – unlike this group.
Vessel Education Programs

Dock Talks

During the spring and summer, the BC Cetacean Sightings Network visits marinas and festivals throughout coastal BC to educate boaters about the Be Whale Wise Guidelines and the threats that cetaceans face.  Contact us at [email protected] if you would like us to visit your marina!

Marine Education and Research Society

The Marine Education and Research Society (MERS) is a registered Canadian charity dedicated to promoting conservation and understanding of marine ecosystems through scientific research, environmental education, and marine wildlife response. Their See A Blow? Go Slow campaign informs recreational boaters of the key points to avoid marine mammal contact or collision.

Robson Bight Warden Program

The Robson Bight (Michael Bigg) Ecological Reserve (RBMBER) was established by BC Parks in 1982 to provide an area free from boat traffic for killer whales that use the area to feed on abundant runs of salmon and rub on the smooth pebble beaches in the reserve (this behaviour is unique to northern resident killer whales). Since 1987, BC Parks has funded the Robson Bight Warden Program which informs boaters in the area of the ecological reserve and the Be Whale Wise Guidelines. Currently the Warden Program is run by Cetus Research & Conservation Society.


Straitwatch is a marine mammal monitoring and education program operated by Cetus Research & Conservation Society.  Straitwatch operates in Johnstone Strait and Haro Strait to monitor the activities around local marine mammals, especially killer whales, and provides boaters with information on local marine species and marine mammal viewing guidelines.


In Washington State, the Whale Museum on San Juan Island established Soundwatch, which conducts important on-the-water vessel education and monitoring.

What can you do to help?


Follow the Be Whale Wise Guidelines

Follow the Be Whale Wise Guidelines when out on the water.  Slow down to less than 7 knots when within 400m of whales.  Do not approach any marine mammal within 100m (200m for killer whales).

Report Marine Mammal Harassment and Violations

In Canada: 1-800-465-4336

In the USA: 1-800-853-1964

Watch Whales from Shore

The BC Cetacean Sightings Network has partnered with the Whale Trail to establish a network of land-based whale watching sites in British Columbia.  Since 2015, 12 sites have been established throughout BC. Learn more about BC’s land-based whale watching initiative, the Whale Trail BC.

Tools for Commercial Mariners

If you belong to a professional marine organization and are a pilot or member of the bridge crew of a ship, use the WhaleReport Alert System to receive real-time alerts of whales in your vicinity.  Mariners can learn more about their impacts and mitigation measures to vessel disturbance in the Mariner’s Guide to Whales, Dolphins, and Porpoises of Western Canada.

  1. Erbe C., Reichmuth C.J., Cunningham K., Lucke K. and Dooling R. (2016) Communication masking in marine mammals: A review and research strategy. Marine Pollution Bulletin 103: 15-38.
  2. Holt, M.M, Noren, D.P., Viers, V., Emmons, C.K., Veirs, S. 2009. Speaking up: Killer whales (Orcinus orca) increase their call amplitude in response to vessel noise. Journal of Acoustic Society of  America. 125 (1): EL27-EL32.
  3. Fisheries and Oceans Canada (2009) Management Plan for the Pacific Harbour Porpoise (Phocoena phocoena) in Canada. Species at Risk Act Management Plan Series. Fisheries and Oceans Canada, Ottawa. v + 49 pp.
  4. Lachmuth, C., Barrett-Lennard, L.G., Steyn, D.Q., Milsom, W.K. (2011) Estimation of southern resident killer whale exposure to exhaust emissions from whalewatching vessels and potential adverse health effects and toxicity thresholds. Marine Pollution Bulletin 62: 792-805.
  5. Lusseau, D., Bain, D.E., Williams, R. Smith, J.C. (2009) Vessel traffic disrupts the foraging behaviours of southern resident killer whales, Orcinus orca. Endangered Species Research 6: 211-221.
  6. Lusseau, D., Bejder, L. (2007) The long-term consequences of short-term responses to disturbance experiences from whalewatching impact assessment. International Journal of Comparative Psychology 20: 228-236.
  7. Neilson, J. L., Gabriele, C.M. (2010) Results of humpback whale population monitoring in Glacier Bay and adjacent waters: 2010. Report to the National Park Service, Glacier Bay National Park and Preserve, Gustavus, AK. 20 pp.
  8. Noren, D., Johnson A.H., Rehder D., and Larson A. (2009) Close approaches by vessels elicit surface active behaviors by southern resident killer whales. Endangered Species Research 8:179–192.
  9. Province of British Columbia (2016). “Marine Emissions”. B.C. Air Quality. Retrieved from: marine-emissions.html)
  10. Thorpe, L., Personal Communication, April 2011 p.c (2011)
  11. Williams, R., Lusseau, D., Hammond, P. (2006) Estimating relative energetic costs of human disturbance to killer whales (Orcinus orca). Biological Conservation 133(3): 301-311.
  12. Williams, R., Krkosek, M., Ashe, E.  Branch, T.A., Clark, P.S. Hammond, P., Hoyt, E.,  Noren, D.P., Rosen, D., Winship, A. (2011) Competing conservation objectives for predators and prey: estimating killer whale prey requirements for Chinook salmon PLoS ONE 6: e26738.