Local scientists have begun looking for ways to combat Undaria pinnatifida, an aggressive species of Japanese kelp that has invaded the California coastline.
David Chapman, professor of marine biology, and third-year marine science graduate student Marla Ranelletti are spearheading the research on the kelp, thanks to $98,000 in funding provided by the National Sea Grant College Program over the past two years. Chapman said this particular seaweed was first spotted in Southern California harbors in 2000, and was found to have spread to Santa Barbara Harbor in 2001.
Ranelletti said the kelp, which is native to the Sea of Japan, was most likely transported to California in the ballast water of large ships. She said the microscopic spores called gametophytes that the kelp uses to reproduce could easily have hitchhiked on ships across the Pacific Ocean undetected. Currently, little is known about the effects that the invasive kelp may have on the local ecosystem.
“We don’t know how much of a problem it’s going to be,” Ranelletti said. “Right now, the focus is on controlling it.”
Undaria is nearly impossible to exterminate, Ranelletti said, because uprooting the kelp releases seeds that are too small to see underwater, which then take hold and grow into new plants. It has not yet spread out of harbors in California except on Catalina Island, where Ranelletti said an outside population is present but not spreading. The kelp has made its way all over the world, and Chapman said it is “getting to the problem stage” in New Zealand.
“I think the advantage we have here is that we caught the invasion early,” Chapman said. “If we had found out about it eight or so years down the road, it would have been a completely different ballgame.”
Ranelletti said she and Chapman are currently working with Santa Barbara Harbor authorities and the California Department of Fish and Game to educate the public about the kelp, and UCSB divers have been assisting with containment efforts. John Ugoretz, senior marine biologist for the Department of Fish and Game, said his biggest concern was to keep the seaweed from getting out into the wild.
“The biggest fear we have locally is to keep the kelp from spreading from the harbors into the natural environment,” Ugoretz said.
The kelp is farmed for use in food in several countries. Chapman said it is often packaged as wakame, and is an ingredient in miso soup. He said other common uses for kelp form a $2 billion dollar per year industry and include the production of algenic acid, which is used as a gelling agent in products like toothpaste and gummy bears and to make liquid fertilizer. However, he cautioned that trying to farm it would not be wise at this point.
“At this time, it’s not a good idea to start growing it as a crop,” Chapman said. “You would almost certainly create problems with the ecosystem.”
Ranelletti said the kelp grows to a maximum of about five to six feet in length and is composed of a long, leafy section called the blade, a stalk called the sporophyll, and a small root-like section called the holdfast. She emphasized that the entire plant must be pulled up, or it will just grow back from the stalk, which contains the spores. She said she hoped to be able to create a poster instructing boaters on how to remove the kelp properly in the near future, as the kelp’s reproductive season is just beginning.
Since only one and a half years remain on the grant, Ranelletti said she hoped her research would progress quickly. However, she said she hoped the kelp itself would not experience nearly the same rate of development.
“Hopefully, it will be a very slow timeline for the problems associated with the kelp.”