Species Information

Red alga (Grateloupia turuturu) Red alga (Grateloupia turuturu)
Courtnay Hermann
Red alga (Grateloupia turuturu)
Courtnay Hermann
Red alga
Grateloupia turuturu

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  • First found on eastern North American shores in 1996 in Narragansett Bay
  • Northward spread into Gulf of Maine apparently limited by intolerance of very cold water

  • Thin, pink to maroon blades, often with bladelets (pinnae) at base, and a distinctly gelatinous, slippery texture
  • Variable growth forms (divided or undivided, varying blade shapes)
  • Grows singly, but more typically in clumps of up to 8 individuals
  • Grows to full lengths in late summer and early fall, then reduces to crust-like form for overwintering
  • Can grow up to 9 ft (3 m)

  • Shallow water to depths of 6.5 ft (2 m), attached to firm surfaces
  • Prefers protected waters such as tidal pools
  • Believed to be unable to survive very cold water

Known Distribution in the Northeast
  • Boston Harbor to Long Island Sound
  • Native to the Pacific Ocean, possibly Japan

  • Growth pattern and habitat preferences make it a threat to native red algal species, particularly Palmaria palmata and Chondrus crispus
  • Broad blades may shade other algae, preventing their growth

Red alga (Grateloupia turuturu)
A. Pappal
Red alga (Grateloupia turuturu)
A. Pappal
Red alga (Grateloupia turuturu)
A. Pappal

Protecting the marine and freshwater resources of the Northeast from invasive aquatic nuisance species