Giant Sea Kelp Invades San Francisco Bay

San Francisco Bay finds its waters infiltrated by a kelp villain. The culprit? “Undaria pinnatifida,” also known as wakame and used in miso soup. It reportedly grows up to an inch a day and kills native kelp.

Photo Credit: mikebairdKelp


“I was walking in San Francisco Marina, and that’s when I saw the kelp attached to a boat. It was 6-foot long, and there is nothing here in the bay that gets to that size. I didn’t want to believe what it was, it’s depressing.” said biologist Chela Zabin from the Smithsonian Environmental Research Center in Tiburon.
So where did the sea monster… kelp come from? Chances are it came to California on oyster shipments and ship hulls, and possibly from introduction through intentional cultivation.

Is it really a sea monster? It was recently nominated to be included in a list of the 100 worst invaders according to the Global Invasive Species Database.

Native kelp is a crucial habitat for marine life like otters and fish. Marine biologists say the new kelp damages ocean ecosystems because it chokes off the sunlight that native kelps require. Undaria pinnatifida releases millions of spores that spread out through the ocean currents but the hope is that secluded marina currents will keep the spread more contained.

The kelp was first found in Los Angeles harbors in 2000 and began growing its way up the coast. A year later it was on Catalina Island and Monterey Bay. Since then, aggressive eradication efforts have attacked the kelp and had been successful in keeping the kelp out of San Francisco Bay-until now.

Federal funding for eradication equipment is gone, reducing the number people who can battle the kelp. Eradication efforts in San Francisco’s Fisherman’s Wharf have started, with divers pulling the kelp off everywhere they find it-monthly Bay checks are planned, but no one is sure whether the divers got everything or if the volunteers can successfully keep the kelp from spreading.

If you live in the San Francisco Bay area and want a blue living idea, volunteering to help battle the invasive kelp is a great option.

“In 10 years I’m guessing Undaria is going to be all over the place. It’s not a problem getting smaller in scope, it’s getting worse and worse… If it’s restricted to two docks in the marinas in San Francisco Bay, we’ll have a chance. If it’s spread beyond those places, it may be a lost cause,” said Zabin.

Related Posts

Affiliate Policy (full policy): Posts may contain links to outside vendors that pay us a commission when you purchase from them, at no additional cost to you. Thank you in advance for supporting our site.

Author: Scott James

Leave a Reply

Your email address will not be published. Required fields are marked *