More on California’s rogue seaweed

Scientists reported last week that they’ve found genetic confirmation of their assumption that a newfound rogue alga in California waters is the same strain that has been smothering seafloor communities in the Mediterranean (SN: 7/4/98, p. 8: https://www.sciencenews.org/pages/sn_arc98/7_4_98/bob1.htm).

The scientists compared gene sequences in Caulerpa taxifolia recently discovered in California and in specimens of the alga collected in the Mediterranean Sea and various aquariums (SN: 11/21/98, p. 332). “All sequences were identical,” reports Olivier Jousson of the University of Geneva in Chêne-Bougeries, Switzerland. His team’s findings appear in the Nov. 9 Nature.

The California specimens came from two sites: a lagoon in San Diego county where eradication began in July (SN: 8/5/00, p. 94: Available to subscribers at Death for the killer seaweed) and a subsequently identified, several-year-old invasion in a cement-walled pond in Orange County. Both invasions trace to hobbyists who dumped aquarium contents into local waters.

Rachel Woodfield, the San Diego–based consulting biologist who identified both invasions, says that her team began efforts to smother and poison the resilient algae at the second site last month. However, that wasn’t before some rogue algae had drained into and established itself in Huntington Harbor. New filters should keep any more from escaping, Woodfield told Science News. She expects soon to launch efforts to eradicate the third, small invasion.