Invasive Seaweeds and Hull Fouling Species

Filograna implexa - Visit ITIS for full scientific classification. 

Filograna implexa (in foreground). Photo by Carrie Culver © 2008 Regents, University of California.

• Small, tube-dwelling, marine worm.
• Forms long, very thin, white calcareous (chalk-like) tubes in dense aggregations.
• Pinkish-grey colored bodies.
• When viewed under a microscope, body segments and feather-like tentacles can be seen.

• Occurs in subtidal and low intertidal areas.
• Like other tubeworms it encrusts hard surfaces including: rocks, shells, other marine animals, vessel hulls, piers, etc. 

• Spread by attaching to vessel hulls, from which larvae swim to settle on surfaces in marinas.
• Found worldwide, including in California. 

• Filter-feeder; uses feather-like gill tentacles to capture particles in the water.
• Reproduces asexually by budding or sexually by releasing sperm and eggs into the water, where they unite to form swimming larvae.

• The chalky tubes form crusts on boat hulls.
• This fouling growth roughens the hull’s surface, creating friction or “drag” that slows sailboats and increases fuel consumption for powerboats.
• Tolerant of copper in antifouling paint, and are very difficult to remove.

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