Feature Story                                                           October 2011 

Volunteers in San Francisco Bay Remove Hundreds of Pounds of an Invasive Kelp from Local Marinas

Over 150 volunteers over the last two years have been working to remove kelp from marinas in San Francisco Bay. The kelp Undaria pinnatifida, also known as Asian Kelp, Wakame or just Undaria, is native to the northwest Pacific - Korea, China, Hong Kong, and Japan – where it is cultivated as a food plant. Starting in the 1980s it was introduced to France, New Zealand, Australia, Argentina, and California. Undaria is a fast-growing kelp that fouls ship hulls, nets, fishing gear, moorings, ropes, and other marine structures. Fouling on boat hulls was the most frequent means of introduction to all these areas. As a fouling species Undaria causes economic and ecological damage across the introduced range and competes for light and space with native populations of marine algae, plants and animals, altering native ecosystems.

The first discovery in California was at Cabrillo Beach, Los Angeles in 2000. Subsequent to that discovery, it was seen in several locations in Southern California including Santa Barbara Harbor and a mooring in a kelp bed near Santa Catalina Island, and within a year had spread to Monterey Harbor. Attempts to control its spread in Santa Barbara and Monterey harbors were launched late and were underfunded. Undaria moved north and became established at Pillar Point Harbor, in Half Moon Bay, at the San Francisco Marina and South Beach Harbor Marina in San Francisco Bay in 2009.

Lead Scientist Dr. Chela Zabin removing Undaria from a San Francisco Bay marina.

Lead Scientist Dr. Chela Zabin from the Smithsonian Environmental Research Center (SERC) with the help of others from the University of California-Davis, the California State Lands Commission, US Fish and Wildlife Service, the National Oceanic and Atmospheric Administration, and the US Department of Agriculture have been working with community groups such as San Francisco Baykeeper and local volunteers to remove the kelp by hand from infested marinas. Dr. Zabin has hosted numerous removal events starting in July 2009 and has led over 150 volunteers in this removal effort. Dr. Zabin and her colleagues also led education campaigns encouraging boat owners, harbor visitors and divers to inspect and remove kelp from their boat hulls, slips, moorings, docks and piers.

Mature Undaria pinnatifida.

From July 2009 to July 2011 volunteers removed 450 pounds of Undaria from San Francisco Marina, 419 pounds from South Beach Marina and 13 pounds from Pillar Point in Half Moon Bay. A local aquarium, Aquarium of the Bay, “adopted” a fourth site, and removed 32 pounds over two months. Volunteers were encouraged this spring when no Undaria was found at the San Francisco Bay marinas from March to July 2011. But before they could claim victory, the kelp returned in August. The return of the kelp was expected because Undaria has a dormant stage that can remain viable for up to two years. Volunteers had seen a similar drop at Pillar Point before seeing the kelp return. But it is noteworthy that in other locations in the Bay where volunteers were not actively removing the kelp, Undaria was flourishing. Dr. Zabin suspects that the volunteer efforts coupled with a long, late rainy season, which lowered salinity in the Bay, may have been the cause of the drop in populations.

The removal efforts have been unfunded since March 2011, so successful management of this pest is dependent upon volunteer efforts. Volunteers are planning to continue the project into the future, with the plan of having individuals or groups “adopt” a single marina. In the meantime, a small grant to SERC from California Sea Grant is funding the development of a web-based citizen science early detection program.

Carliane Johnson, a marine biologist who recently moved to California from the East Coast, volunteers her time to remove Undaria because she knows firsthand how harmful non-native and invasive species can be to an ecosystem. “I’m originally from Florida, where non-native plants and animals have also caused a lot of damage. It’s very difficult to completely remove these invaders, but I’ve seen the positive results when people remain diligent. My mother, who was in her 70s at the time, took it upon herself to remove Melaleuca (also known as punk tree) from her two-acre property in South Florida. In the 1930s, the seeds of this Australian tree had been scattered from airplanes throughout the Everglades to try to drain it. It took my mother years to remove the mature trees, and she continues to pull new sprouts, but she was successful. Since Pillar Point Harbor is my backyard now, I hope to do the same here with Undaria.”

Association for Women in Science, East Bay, California Chapter, volunteer, Marianne Kavanagh, is a research biologist who, through partnering with the research staff at SERC, has exposed girls interested in science to field research by bringing them out as removal volunteers.“It is one thing to read about the scientific process after the studies have been reported, published, and printed in biology textbooks, but quite another to participate in ongoing studies such as these ecological studies.” 

Volunteers Gemma, Brianna, Isabel and Morgan removing Undaria from South Beach Harbor Marina in San Francisco Bay. Photo by Marianne Kavanagh
The girls benefit twofold from their volunteer efforts. During their searches for Undaria the girls learn how an invasive species can be removed from its adopted habit and how species live together and adapt to the San Francisco Bay ecosystem through their observations of native algae populations. They also get the satisfaction of doing something to help the local environment. Fourteen year old Brianna says she wants to be a marine biologist, is concerned about ocean health and has been picking up trash in town to prevent it from reaching the ocean. For sixteen year old Morgan "it was a great feeling to be protecting the San Francisco Bay from Undaria. Most people don't realize that even doing something simple like taking Undaria out of the Bay will help our ocean survive and be prosperous.” For thirteen year old Isabel volunteering “was fantastic. I felt like I was doing something great for the environment. I loved the feeling of looking in the water and finding the Undaria." And Gemma, thirteen, says, "I loved hanging out with my cousins and doing something for the environment at the same time. It was really fun to try to find which plants were invasive. I loved sticking my hands in the water. I think a lot more people should volunteer to do this. It is so much fun. And, sometimes you see sea lions and other animals."

If you’d like to join these great volunteers in their efforts to help protect San Francisco Bay and learn about scientific research at the same time visit our website and contact Dr Zabin (zabinc@si.edu, 415-435-3528) to sign up for the next removal event or for information on how you can adopt a marina. 

Check out this great video created by our young volunteers!