UC Davis marine invasive species expert Susan Williams will address the U.S. House of Representatives' Ocean Caucus on Monday, July 22, about the threat of one of the world's 100 worst invaders, the seaweed Caulerpa taxifolia.

Caulerpa taxifolia invaded sensitive marine habitat in Southern California in 2000. Williams, a professor of environmental science and policy and director of the UC Davis Bodega Marine Laboratory, is an academic member of the management team assigned to eradicate Caulerpa in California.

Williams is expected to tell the House Ocean Caucus that the eradication job will take a long time and require continued funding. If it is not stopped now, Caulerpa is expected to spread and displace native marine communities, as it has in the Mediterranean Sea.

Williams also will explain that prevention of new invasions is always more cost-effective than eradication. Because Caulerpa invasions begin when the seaweed is released from public and private aquariums, preventing new invasions will require the cooperation of the aquarium and aquatic ornamental trades. In California, these trades are being promoted as "environmentally sustainable development," Williams says, and most policy-makers and resource managers are not aware of the risk of introducing invasive aquarium species like Caulerpa.

Williams' address will take place noon to 1:30 p.m. on Monday, July 22, in Rooms B338-9 in the Rayburn House Office Building. Media are welcome. Also speaking will be James Carlton of Williams College, Mystic, Conn., on current and historical invasions. Carlton received his Ph.D. from UC Davis.