It was nominated one of the 100 worst invasive species in the world. Undaria is commonly initially introduced or recorded on artificial structures, where its r-selected growth strategy facilitates proliferation and spread to natural reef sites. Undaria populations make a significant but inconsistent contribution of food and habitat to intertidal and subtidal reefs. Undaria invasion can cause changes to native community composition at all trophic levels. As well as increasing primary productivity, it can reduce the abundance and diversity of understory algal assemblages, out-compete some native macroalgal species and affect the abundance and composition of associated epibionts and macrofauna: including gastropods, crabs, urchins and fish. New Zealand In New Zealand, Undaria pinnatifida was declared as an unwanted organism in 2000 under the Biosecurity Act 1993. It was first discovered in Wellington Harbour in 1987 and probably arrived as hull fouling on shipping or fishing vessels from Asia. Wakame is now found around much of New Zealand, from Stewart Island to as far north as the subtropical waters of Karikari Peninsula. It spreads in two ways: naturally, through the millions of microscopic spores released by each fertile organism, and through human mediated spread, most commonly via hull fouling and with marine farming equipment. It is a highly successful and fertile species, which makes it a serious invader. However, its impacts are not well understood and vary depending on the location. Even though it is an invasive species, in 2012 the government allowed for the farming of wakame in Wellington, Marlborough and Banks Peninsula. United States The seaweed has been found in several harbors in southern California. In May 2009 it was discovered in San Francisco Bay and aggressive efforts are underway to remove it before it spreads. See also Kelp Kombu Laverbread References External links Wakame Seaweed at About.com AlgaeBase link Undaria pinnatifida at the FAO Undaria pinnatifida at the Joint Nature Conservation Committee, UK Global Invasive species database Undaria Management at the Monterey Bay National Marine Sanctuary Alariaceae Algae of Korea Marine biota of Asia Edible algae Edible seaweeds Japanese cuisine terms Plants described in 1873