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.
- Noise. Motorized 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 , 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 BC, 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.
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
What can you do to help?
Report Marine Mammal Harassment and Violations
In Canada: 1-800-465-4336
In the USA: 1-800-853-1964
Watch Whales from Land
The Whale Trail is a series of sites that run from California to British Columbia where the public may view marine mammals from shore. Most sites include interpretive signage where viewers can learn more about the species commonly spotted in that region.
Read the Mariner's Guide
Large vessel 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- Province of British Columbia (2016). “Marine Emissions”. B.C. Air Quality. Retrieved from: http://www.bcairquality.ca/topics/ marine-emissions.html)
- Thorpe, L., Personal Communication, April 2011 p.c (2011)
- 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.
- 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.