Attack of the Killer Algae

Since 1991, French scientists and authorities have tried to destroy the seaweed by smothering the plants with salt, sucking them up with vacuum hoses, uprooting them by hand, and smothering them under tarps. In every case, the algae quickly grew back. Fortunately, eradication efforts in Southern California started early. Because both of the affected sites are located in nearly enclosed lagoons, scientists hope the seaweed can be completely wiped out before it spreads to the open ocean and beyond.

If the battle is successful, the next battle, believe it or not, will be with aquarium hobbyists who greatly prize the Caulerpa genus, which comprises 73 species, many of which are difficult to tell apart even for experts. When state legislators proposed a bill banning possession or sale of the entire genus, there was a nationwide outcry, saying that banning the entire genus would have dire effects on aquarium owners. In the end, legislators banned only nine Caulerpa species: three known to be invasive and six look-alikes. But many are concerned that the law will be unworkable because of the difficulty of telling Caulerpa species apart. The scientific consensus that all Caulerpas should be banned from the aquarium trade.