Research ProjectManagement of Vessel Biofouling

Reducing the Risk of Marine Invasions Due to Vessel Fouling

  • A fouled propeller

    A example of extreme biofouling on a boat propeller. Photo by Ian Davidson

  • A diver next to a commercial ship

    A diver surveying biofouling on a commercial ship. Photo by Ian Davidson

Affiliated Labs

Project Goal

We study current and emerging technologies and management practices aimed at reducing biofouling on ships in order to develop risk assessments for various biofouling management scenarios.


Biofouling, the growth of marine life on the wetted surfaces of ships and maritime structures, is a major pathway for the introduction of non-native marine species.  In some locations, such as the Hawaiian Islands, more non-native species were accidently introduced through biofouling than through the better-known vector of ballast water. Addressing biofouling is crucial to reducing the spread of non-native species.
Resource managers are looking for options for managing biofouling and are developing regulations and recommended practices for ship operators and boat owners at global, national, and regional scales. Research into the best methods for biofouling prevention, such as the removal of accumulated biofouling from vessels, and the relative risk of various management scenarios is ongoing around the world.
To aid managers in weighing options for biofouling management, we combined literature-based research on current policy and the efficacy, availability, and associated risk of current and developing technologies for cleaning vessels with data with data on ship travel patterns, hull-husbandry practices and biofouling to develop possible management options. We provided this information for Puget Sound to the state of Washington, and in collaboration with the consulting firm SAIC, provided updated information to the US Coast Guard on current technologies and biofouling policies around the world. We are now working with Hawaii’s Department of Land and Natural Resources to review in-water cleaning technologies and to develop a risk-assessment model to guide policy regarding in-water cleaning.
Our research helps managers weigh the relative risks of various biofouling management options, such as in-water cleaning.
Diver under a recreational boat
Periodic cleaning of vessels is routinely done in water to remove accumulated biofouling, as this is far less costly than hauling out. Doing so helps vessels operate better and can help reduce the spread of non-native species. However, as it is typically practiced, in-water cleaning can also release viable non-native species and toxic contaminants from anti-fouling paint to the environment. Photo by Ian Davidson
Barnacle and mussel from a boat hull
Cleaning out of water is more costly, but it may pose less of a risk to the environment than in-water cleaning, especially if the removed fouling is contained and disposed of on land. However, some biofouling species, such as these barnacles, can even survive a cleaning and anti-fouling paint (the red coating) application in dry dock! Photo by Chela Zabin
Boat hauled out of the water for cleaning
Hauling out and cleaning your boat thoroughly before leaving your homeport is critical to preventing the spread of species along the coast and between bays. Photo by Monaca Noble


Hughes, Kevin A. and Ashton, Gail V. 2017. Breaking the ice: the introduction of biofouling organisms to Antarctica on vessel hulls. Aquatic Conservation: Marine and Freshwater Ecosystems, 27 (1) , 158-164.

Moser, Cameron S., Wier, Timothy P., Grant, Jonathan F., First, Matthew R., Tamburri, Mario N., Ruiz, Gregory M., Miller, A. Whitman and Drake, Lisa A. 2016. Quantifying the total wetted surface area of the world fleet: a first step in determining the potential extent of ships' biofouling. Biological Invasions, 18(1): 265-277. doi:10.1007/s10530-015-1007-z

Davidson, Ian C., Brown, Christopher W., Sytsma, Mark D. and Ruiz, Gregory M. 2009. The role of containerships as transfer mechanisms of marine biofouling species. Biofouling, 25(7): 645-655. doi:10.1080/08927010903046268

Feature Stories

Uncharted Waters: What Barnacles Can Teach us About Species Dispersal. By Emily Anderson and Monaca Noble. July, 14, 2016

Ships’ Marine Hitchhikers. By Ian Davidson. November 2012


Chela Zabin (;
Ian Davidson (