Taxonomic diversity, geographic distribution, and commercial availability of aquarium-traded species of Caulerpa (Chlorophyta, Caulerpaceae) in southern California

Fourteen taxa (ten species) of Caulerpa were identified from retail aquarium outlets in southern California, USA. Seaweeds were sold in 58% and species of Caulerpa in 52% of the 50 stores visited between November 2000 and August 2001. Caulerpa serrulata var. hummii (18%), C. taxifolia (14%), C. racemosa (14%), and C. racemosa var. lamourouxii (14%) were the most common taxa. The fourteen aquarium-traded Caulerpa taxa are distributed worldwide. Only two (C. ashmeadii and C. microphysa ) are confined to the tropics whereas 12 have distributions that extend into temperate seas. These temperate components to their distributions indicate that, if introduced, multiple taxa of aquarium-traded Caulerpa might be capable of establishing invasive populations in southern California or other temperate waters. The widespread availability of Caulerpa taxa, including many with distributions ranging from the tropics to temperate waters, demonstrates that the aquarium industry is potentially a significant source for Caulerpa introductions.