California Aquatic Invasive Species (AIS)
University of California
California Aquatic Invasive Species (AIS)

Invasive Seaweeds and Hull Fouling Species

Killer Seaweed

Scientific Name

Caulerpa taxifolia - Visit ITIS for full scientific classification. 



  • Fast-growing, bright green feather-like fronds, 3-5 inches tall, arising from horizontal stems (stolons).
  • Used as a decorative saltwater aquarium plant.
  • Occurs as both a native and an invasive strain.
  • Easily confused with other species of Caulerpa.
  • Found on rocky, sandy and muddy bottoms in shallow lagoons, or at deeper depths.
Invasion Pathways and Distribution
  • Broadly distributed in tropical seas.
  • Invasive aquarium strain spreads when released in the sea.
  • Can grow from small fragments transported by boat anchors and fishing gear.
  • Now found in the Mediterranean Sea and Australia.
  • Introduced to two small lagoons in California in 2000 and removed with great effort and expense.
  • Now illegal to possess, sell, or transport in California.
Life History
  • Sexual reproduction observed in the native strain, but not in the invasive aquarium strain, which reproduces through fragmentation.
  • Grows and spreads rapidly, forming dense mats.
  • Outcompetes native species for space and light.
  • Contains toxic substances that make it distasteful to animals that eat seaweeds.
References and Useful Links

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

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