Harbor seal (Phoca vitulina) tolerance to vessels under different levels of boat traffic

Vessel traffic is increasing in the Puget Sound region. A 2017 article in the journal Aquatic Mammals looks at the potential impacts that increasing vessel disturbance may have on resident harbor seal populations and how future management decisions may need to look at variable buffer zones related to level of human activity.

Harbor seals at haulout site. Photo courtesy of WDFW: http://wdfw.wa.gov/wildwatch/sealcam/.
Harbor seals at haulout site. Photo courtesy of WDFW: http://wdfw.wa.gov/wildwatch/sealcam/.


Disturbance can be defined as any stimulus that, either as a result of natural or human-derived sources, causes a deviation in an animal’s typical behavior (Suryan & Harvey, 1999; Jansen et al., 2010). Vessel traffic is an extensive source of anthropogenic disturbance to marine mammals as it can influence reproductive success, alter social communication and behavior, change feeding strategies, and cause displacement (Johnson & Tyack, 2003; Williams et al., 2006; Wright et al., 2007; Bejder et al., 2009; French et al., 2011; Atkinson et al., 2015). Given that over 41% of the world’s human population lives within 100 km of the sea coast (Martinez et al., 2007) and that activities such as shipping and recreational boating are likely to increase (Kakoyannis & Stankey, 2002; Tournadre, 2014), coastal marine mammals, such as pinnipeds, are particularly susceptible to disturbances in regions where vessel traffic overlaps with productive coastal waters (Jefferson et al., 1993; Robards et al., 2016). Hence, studying how pinnipeds respond to the expected increase in coastal human activities is important to the conservation and management of these populations.


Cates, K., & Acevedo-Gutiérrez, A. (2017). Harbor Seal (Phoca vitulina) Tolerance to Vessels Under Different Levels of Boat Traffic. Aquatic Mammals43(2), 193.

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About the Author: 
Kelly Cates and Alejandro Acevedo-Gutiérrez are affiliated with the Department of Biology at Western Washington University, 516 High Street, Bellingham, WA 98225-9160, USA.