Your help is needed to report new sightings of the fast-growing, invasive Asian kelp, Undaria pinnatifida.  Uncontrolled, it can become a pest on boat hulls, moorings, ropes, fishing gear, docks, and aquaculture structures. It could have profound effects on native species, as well as Humboldt Bay's oyster industry.

Early detection can help prevent further spread of this invasive kelp. For more info, visit the Smithsonian Environmental Research Center's Marine Invasions Research Lab.

First reported from the LA-Long Beach Harbor in 2000, it has since spread as far north as San Francisco Bay. Native to Japan, China, and Korea, it can spread by hitchhiking on boats, anchors, floats, and aquaculture gear.


What you can do:

  • Learn to identify the invasive kelp Undaria pinnatifida
  • Look for this kelp while enjoying our waterways
  • Regularly inspect and remove fouling from your boat, especially 
before cruising to a new location

If you believe you have found Undaria, please take a photograph and upload it at Remove the kelp if you can do 
so safely and store in a plastic bag until we can confirm its identity. Do not dispose of it in the water. If you have questions, contact Smithsonian Environmental Research Center's Marine Invasions Research Lab at (415) 435-7128, This email address is being protected from spambots. You need JavaScript enabled to view it..