Sea creatures get non-toxic brush-off.

Barnacles, mollusks, and other forms of sea life that take up residence on ship hulls can slow vessels by several knots, hike fuel consumption by as much as 40%, and cause corrosion. These marine animals also foul fishing nets, harbor construction, and power plant water-intake pipes. Traditional organotin or cuprous oxide paints used to battle this fouling are effective, but toxic.

The ultimate goal in the field is to develop self-cleaning coatings that shuck off foulants as a ship glides through water, notes Judith Stein of the General Electric Research and Development Center, Schenectady, N.Y., but that could be a long way off. For now, scientists are working on ways to prevent marine organisms from attaching to hulls in the first place or to make them easier to remove.

One source of these anti-foulant compounds could be the sea itself. For example, many marine sponges produce anti-fouling...