English: Undaria pinnatifida is a brown seaweed that reaches an overall length of 1-3 m. Undaria is a native of the Japan Sea and the northwest Pacific coasts of Japan and Korea. In Japan, Undaria, known locally as 'wakame', is extensively cultivated as a food plant. Japanese consumption of the alga is around 200,000 tonnes of fresh or dried plant per annum. Undaria is regarded as a pest because it is highly invasive, grows rapidly and has the potential to overgrow and exclude native seaweeds. It was first detected in Australia in 1988 near Triabunna on the east coast of Tasmania. Over the following ten years it spread along 100 kms of the Tasmanian east coast and also to Victoria - the most likely vector being international shipping.