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Invasive Seaweeds and Hull Fouling Species

Tube worms

  • Scientific Name

    Hydroides spp. (H. elegans, & H. gracilis) - Visit ITIS for full scientific classification. 

  • Description

     

    • Small, tube-dwelling, marine worms.
    • Attach to hard surfaces by forming long, thick, irregularly coiled, white calcareous (chalk-like) tubes.
    • When viewed under a microscope, body segments and feather-like tentacles can be seen.
  • Habitat
    • Occur in subtidal and low intertidal areas.
    • Abundant in marinas, docks, and rocky environments with many hard surfaces.
    • Found on a variety of natural and man-made surfaces including: woody debris, shells of other animals, oyster reefs, rocky reefs, pier pilings, vessel hulls, intake lines, canals, etc. 
  • Invasion Pathways and Distribution
    • Spread by attaching to vessel hulls, from which larvae swim to settle on surfaces in marinas.
    • One species, Hydroides elegans, is originally described from Sydney, Australia.
    • The exact native origin is assumed to be somewhere in the Indo-Pacific.
    • The origin of a close relative, H. gracilis, is Pacific Grove, California.
    • Both are found worldwide, including all along the California coast.
    • See NEMESIS for a distribution map. 
  • Life History
    • Filter-feeders; use feather-like gill tentacles to capture particles in the water.
    • Reproduce sexually by releasing sperm and eggs into the water, where they unite to form swimming larvae
  • Impacts
    • Hydroides elegans is a well-known, dominant fouling species with the potential to outcompete native species for space and food.
    • The chalky tubes form heavy 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.
  • References and Useful Links

    For references by category and links to other useful AIS sites see our LEARN MORE page.