Risk of biodiversity changes in native macroalgal communities from Argentina by the introduction of brown seaweeds along the Atlantic coast: First record of Saccharina sessilis

PARODI, ELISA R.; GAUNA M. CECILIA; FERNANDEZ, CAROLINA; CACERES, EDUARDO J.

Mar del Plata

Congreso; Cerf 2012; 2012

The introduction of marine exotic species may result in severe ecological perturbations in communities, leading to local exclusions or sharp decreases of native species. Seaweed invasions may result from intentional or accidental introductions as they have been reported worldwide. During the past decade the presence of new brown algae species were reported in the Patagonian coasts. In 1992 it was reported the introduction of Undaria pinnatifida, a brown alga native to northeastern Asia, which is successfully invasive in several areas of the world. U. pinnatifida was detected in Golfo Nuevo, extending rapidly its presence southwards to Santa Cruz Province and recently northwards to Mar del Plata (Buenos Aires Province). In 1997 other brown seaweed, Sporochnus pedunculatus was for first time detected in Las Grutas, (Río Negro Province). During January of the current year we observed and collected Saccharina sessilis (Phaeophyceae) fronds in Pehuen–Co beach (Buenos Aires Province). S. sessilis is a dominant kelp species found in moderately to highly wave-exposed sites in the lower intertidal zone in the Northeastern Pacific Ocean and in Asia. In Argentina, sporophytes were up to 50 cm in length, flexible, yellowish brown when alive and dark when dry. Juveniles were composed by a blade and a holdfast like haptera that disappeared in adults. The blade was ovate and presented a margins entire and undulate or occasionally split. This first report of Saccharina sessilis in Argentina extends its distribution to the southern hemisphere and the Atlantic ocean. Session: Changing baseline populations