Surveys of Undaria pinnatifida (Laminariales, Phaeophyta) in Golfo Nuevo, Argentina

In December 1992, some sporophytes of the Asian kelp Undaria pinnatifida were found growing subtidally at 6 m depth below 'A. Storni' Port, Puerto Madryn, Argentina. During the winter of 1994, the species expanded significantly from its original location. Sporelings appear in early autumn and attain their maximum size (1.65 plus or minus 0.10 m) during winter and early spring, when most of them become fertile. The fronds are lost in summer, with only some holdfasts and sporophylls surviving, and these disappear by the end of summer. The occurrence of U. pinnatifida in Golfo Nuevo is reportedly due to an accidental introduction by cargo ships or fishing vessels arriving from Asian ports.