Marine Biofouling: A Sticky Situation with Global Implications

The most widely accepted method to prevent biofouling is the use of antifouling coatings. Tin-based coatings were effective, but were later determined to be toxic, not only to fouling organisms, but also to other non-target organisms. Concentrations of tin-based coating toxins were found to build in places with heavy boat traffic and limited water circulation to the point where they could harm or destroy mollusk populations by interfering with their growth, reproduction and immunity processes on a cellular level. To address these global environmental concerns, an international treaty signed in 2002 banned the application of paint containing tin on all ships by January 1, 2003 and prohibiting the presence of tin-based antifouling coatings on all ships by January 1, 2008. Since the ban, mariners have turned to coatings with high concentrations of copper or zinc. Although they are not restricted under the law, copper- and zinc-based coatings are suspected to also cause cellular damage to non-target organisms. There are lesser known, more environmentally friendly alternatives to copper- and zinc-based antifouling coatings available, however; some of which photo-chemically produce hydrogen peroxide on the hull’s surface to create a protective barrier. Other products with limited negative environmental impacts like Teflon^®, silicone, and wax curb fouling organism adhesion. Educating mariners about the existence of these safer coating products and encouraging their use is crucial to maintain and protect our valuable oceans.

Another strategy to decrease biofouling focuses on the design of places nautical vessels are housed. Enclosed marinas (.pdf) with more than two hundred boats have limited tide and current activity and are much more likely to contain fouling organisms than unenclosed marinas with less than two hundred boats. Marinas must be developed with input from planners, environmental engineers, and scientists to effectively maximize flushing capacity, thereby minimizing the concentration of marine fouling organisms and boating related contaminants.