Caulerpa
(Caulerpa taxifolia)

Description: Caulerpa resembles a network of bright green feathers, each about 1 cm wide, up to 65 cm high, and spaced about 2 cm apart along a root-like structure. While there are superficially similar native species, Caulerpa is more robust in structure, and has all the feather-like fronds growing in one plane. Moreover, our native species are typically only found in tiny tufts, while a typical early infestation of Caulerpa can measure from one to many meters in size. Note: when collecting a specimen of Caulerpa to bring in for identification, be very careful just to remove one frond without fragmenting the rest of the infestation.

Habitat: Caulerpa can colonize a variety of aquatic settings, such as sandy bottom habitats, rocky outcroppings, and mud flats. It can occupy both polluted and non-polluted waters, of the open coast and bays.

Origin: Northern Australia

Invaded Areas: Southern California, Europe (Mediterranean), and Southern Australia.

Concerns: Caulerpa can spread rapidly, carpeting the substrate and choking out native algae and invertebrates. In the Mediterranean, this species has become remarkably abundant and has grown over rocky reefs and has established itself among coral reef communities. Because of its ability to withstand a wide range of environments, the potential for invasions into new locations is great. Natural predators on Caulerpa are scarce, and its toxic leaves deter algae-eating organisms in newly invaded areas from keeping Caulerpa’s growth under control. While ocean currents may facilitate the transfer of fragments into new locations, it is believed that anchor and fishing lines carrying fronds of Caulerpa are the principal modes of transfer. Moreover, fragments can survive out of water for up to 10 days. Another mode of introduction is through the aquarium trade and dumping of aquarium contents in local bays.