Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

First record and putative introduction of the subtropical brown alga Padina durvillei Bory (Phaeophyceae, dictyotales) in southern California, USA.

Abstract

The subtropical brown alga, Padina durvillei Bory, is common in the intertidal and shallow subtidal habitats in Baja California, Mexico, in both the Gulf of California and on the Pacific coastline. Here we report the first record of this genus in temperate waters of California, USA, in the heavily urbanized, man-made harbor of Marina del Rey in Los Angeles County, located more than 550 km from its northernmost recorded range. A population of several hundred individuals was found in April 2016 in shallow waters attached to silt-covered concrete adjacent to a public boat ramp. The isolated population has persisted through June 2019. Given that the observed P. durvillei population is located near a heavily trafficked public boat ramp, the alga was likely transported from the Baja California region via recreational boating activities, either attached to the hull of a boat or carried on-board and disposed of in the water. Two other locations in the marina were surveyed in 2016 and 2017 with no Padina individuals found, although further sampling and continued monitoring is needed to ensure the alga has not spread. Ideally, an effort should be undertaken to eradicate this species given its isolated distribution and the relatively small spatial extent of the population.