Prickly Seaweed

Acanthophora spicifera

Acanthophora spicifera


  • Thin branches with many radially symmetrical spines
  • Color varies from light yellow, green, brown, to purple
  • Grows on hard substrate including rubble


  • High growth rate
  • Spreads by fragmentation
  • Able to reproduce sexually
  • Introduction unknown; possibly from unintentional hull fouling or ballast water
  • High survival rate when exposed to air; able to retain water


  • Causes shift in ecosystem; what was once coral dominated is now algae dominated with low diversity
  • Habitat loss greatly affects recreational and commercial fisheries
  • Most prolific and abundant in Hawaii


  • Well established on all islands in the main chain