Typical Caulerpa taxifolia is a decorative green alga (or seaweed) native to warm tropical waters that normally grows in small, isolated patches, and is popular with many marine aquarists. However, its popularity might be opening the door to the invasion of this very aggressive Mediterranean strain of alga along U.S. coastlines. Even though this Caulerpa was banned for importation INTO the United States, its possession and sale is still legal under federal law in many states. A suspected means of how this algae spreads is from a plant fragment that gets dumped down a drain that may connect to the ocean when aquarium waste water is disposed of. Ah, so that's how you may be contributing to its release into non-native waters!
A Caulerpa alga closely related to the Caulerpa taxifolia species was cloned and cultured for display at the Stuttgart Aquarium in Germany, and this cloned alga was then shared with aquariums in France and Monaco. Sometime in 1984 this Caulerpa either escaped or was accidentally released into Mediterranean waters and quickly began spreading, and since that time has continued to spread rapidly throughout the Mediterranean region. This very destructive seaweed is strangling and killing coral and other marine animals by growing over sea beds and choking off the nutrients and light from other organisms. The governments of France, Spain, Monaco and Italy have been unsuccessful at combating the spread of this invasive algae, and this species was reported near Sydney, Australia not long ago.
Apparently, this cloned strain can grow in colder waters, both at shallow or deeper depths, where the typical tropical strain can't. It grows much larger and spreads by fragmentation, with a single frond multiplying quickly. It is said to be able to live 10 days out of water, and contains toxins which have a repulsive effect on herbivorous marine animals. Despite bans on its possession in France, Spain, and Australia, this dangerous organism has been continued to be transported and sold in the aquarium trade. It has been expected by many scientists that it would only be a matter of time before it started appearing in U.S. waters.
Well it may have arrived! An alien green algae was discovered in Agua Hedionda Lagoon, a coastal lagoon located approximately 20 miles north of San Diego, California on June 12, 2000, with another infestation identified shortly thereafter in Huntington Harbor, in Orange County. The immediate action for eradication of the San Diego outbreak appears to have been successful, and clean up is currently underway in Huntington Harbor. Only time will tell for sure if has been truly eradicated. Efforts are underway to introduce more protective legislation in California to make even the possession and sale of this Caulerpa illegal. Florida has been battling with a similar, closely related Caulerpa alga problem, but the Caulerpa outbreaks in California and Florida are unrelated, because they are different species.
Aside from the possibility of this alga spreading from a plant fragment getting dumped down a drain when aquarium waste water is disposed of, fishing gear, boat lines and anchors all contribute to the localized spreading of this seaweed by breaking off plant fragments, allowing them to it to be carried to other locations for regeneration. Large water vessels from foreign ports that dump their ballast tank water into non-native waters is a potential means of transporting these unwanted alga fragments as well.
Learn to identify this seaweed!
As an aquarist,
boater, fisher person, diver
or snorkeler, find out what you can do to
help prevent the spread of this noxious algae!!!
Early detection is a critical ingredient to prevent establishment of this destructive seaweed along our coastlines. No matter where you live, if you spot it growing in the wild report it to the proper Mediterranean, California, and other state or foreign country authorities immediately!! If you are a diver or snorkeler, DO NOT disturb or try to remove it yourself!! This can only lead to possible regeneration in other areas if fragments are broken off.