Caulerpa taxifolia (Vahl) Agardh (Mediterranean strain)
Marine algae with bright green, pinnate fernlike fronds 5–65 cm long that extend upward from horizontal stolons; stolons to 3 m long, attached to underwater surfaces such as rocks, mud, or sand via rootlike rhizoids.
DNA tests are necessary to distinguish the invasive Mediterranean strain from native Caulerpa taxifolia.
Caulerpa mexicana Sonder ex Kützing [no images provided]
Croatia, France, Italy, Monaco, Spain (Mediterranean Sea, Adriatic Sea), Australia, United States
tropical and temperate coastal lagoons to ocean waters; usually in water to 50 m deep but can grow in water as deep as 150 m
The noninvasive form of Caulerpa taxifolia is native to the Caribbean, Indo-Pacific and the Red Sea. The invasive strain is genetically distinct. It grows more rapidly, tolerates cooler water, and grows at greater depth than the native species. This strain was probably released from an aquarium into the Mediterranean in 1984 and spread rapidly, densely blanketing thousands of acres of underwater surfaces. This alga becomes the dominant species, altering native algal and marine animal communities. There is no sexual reproduction; propagation is purely vegetative. Stem and stolon fragments as small as a half inch can grow into new algae. These fragments are easily transported by boating and fishing activities. Infestations negatively affect tourism, commercial fishing, and recreational activities. Populations of the Mediterranean aquarium strain discovered in 2000 in California threaten native kelp and eelgrass meadows.