06/20/2012 07:40 pm ET Updated Jun 21, 2012

Invasive Brown Kelp From Japan Threatens California Ecosystems (PHOTOS)

For the past three years a highly invasive form of brown kelp, native to Japan, has spread throughout the San Francisco bay. Researchers worry that the alien seaweed could threaten native species and ecosystems in the Pacific Ocean.

The seaweed, more often referred to as Wakame, is a common ingredient in Miso soup and multiplies at an extremely quick rate. Since it was discovered at the San Francisco Yacht Harbor and the South Beach Harbor in 2009, it has already drastically altered the Bay's ecosystem by driving out native kelp.


The discovery of the dangerously invasive species initially sparked widespread alarm among marina workers and biologists who have worked endlessly to get rid of the alien species. Wakame is also responsible for wreaking havoc on ecosystems in Argentina, New Zealand and parts of Europe.

Last year, the Smithsonian Environmental Research Center found the brown kelp clinging to several more places along the Bay including Fort Mason, Pier 39, Fisherman's Wharf, and along the Hyde Street pier. The worst areas of infestation are around AT&T Park and Half-Moon Bay.

The dangerous plant, known scientifically as Undaria pinnatifida, is known to grow on almost any surface and stretch over an inch a day to more than nine feet total. The seaweed can thrive in both cold and warm saltwater.

Wakame can be killed by immersing it in fresh water or subjecting it to heat; however, there is currently no money to fund these tactics. Removing the seaweed is currently an all-volunteer effort.

If the seaweed is not checked, it will eventually eradicate native California counterparts, including the iconic giant kelp that fills the Pacific Ocean. The various fish and other animals that rely on the giant kelp to survive will also suffer as a result.

Click through the slideshow below to see other invasive species affecting ecosystems worldwide: