Agua Hedionda Lagoon Foundation


Caulerpa taxifolia

Crane Standing in Marsh

Our location on the eastern edge of the large expanse of wetlands bordering surrounding our lagoon ideally qualifies the Agua Hedionda Lagoon Foundation to carry out its mission of stewardship of the area, both marshlands and water.

One of our most memorable challenges in recent years was the eradication of the dangerously invasive seaweed that took root in our lagoon and in Huntington Harbor some 65 miles to the north of us.

Caulerpa taxifolia was discovered in Agua Hedionda Lagoon in June 2000. It has been nicknamed "killer algae" because of its devastating effect on marine ecology. It is extremely fast growing and if allowed to become permanently established can destroy and replace coastal marine life such as kelp forests which are home to a wide variety of fish, marine mammals and seabirds. Large areas of the Mediterranean Sea and several sites along the eastern Australian coastline already have been tragically and irreversibly affected.

In an emergency response to this major threat to the health of our lagoon, the Southern California Caulerpa Action Team (SCCAT) was formed to respond quickly to the invasion. Large grants of funds came down from all levels of government and many private organizations. We were proud to have the grant monies administered through AHLF. Many hours were dedicated to this effort.

Diving teams were hired to spread heavy tarps over the expanse of green fronds. These were weighted at the edges and chlorine gas was injected to kill the seaweed. This activity continued for months, while divers checked and re-checked for the unwelcome invader. Caulerpa taxifolia was declared eradicated from Agua Hedionda Lagoon and Huntington Harbor on July 12, 2006.

BEWARE: Because this noxious plant is quite attractive to the eye with its bright green color and gracefully undulating fronds, it seems a natural and desirable addition to home aquariums. But take care! Given its ability to grow so rapidly (more than an inch a day), even the smallest shred of the plant can explode into an ecological menace. It is believed that the original infestation got its start from someone emptying the contents of their aquarium into the lagoon or a storm drain without realizing the consequences of this action.

Laws have been passed at the Federal, State and City level banning possession, sale or transport of Caulerpa taxifolia throughout California. But, just in case, you should learn to recognize this seaweed at home or in or around your boat. If you find it – even a shred – remove it, bag it, and report it to California Department of Fish and Game.

Algerian Sea Lavender

In our continuing effort to remove Algerian Sea Lavender (Limmonium Rasmosisimum or ASL) from our local salt marshes, AHLF, the California Department of Fish and Wildlife (CDFW), and the Carlsbad Strawberry Fields have finalized plans for a broad-spectrum treatment study. This scientific study addresses the effectiveness of solarization, when compared to traditional treatment methods. As we've talked about in previous articles, solarization involves tarping affected areas with heat-trapping plastics, to remove invasive species and their seed banks. The increased soil temperatures and lack of sunlight have been shown to effectively remove ASL, while leaving native vegetation intact.

Retaining the diversity of our salt marshes is important to sensitive marine and bird species. Bird species, like the Belding's Savannah Sparrow (Passerculus sandwichensis beldingi), depend on dense salt-marsh foliage to protect their nests. ASL out competes native vegetation and doesn't provide a suitable structure for nests. The same native foliage also retains narrow, brackish-water channels. These channels are a critical sanctuary for juvenile fish species, including the threatened Tidewater Goby (Eucyclogobius newberryi). Narrow channels keep aggressive, mature fish from entering which provides safe feeding grounds for juveniles.

Treatment started in early December 2017 and involved 5 separate test plots. Each plot contains a control section, a solarization section, and a section treated with traditional methods. These 5 sections will be constantly monitored by AHLF and CDFW staff to check for native species stability, effects on ASL, and tarp integrity. Over the next year 2100 square feet of native vegetation will be reclaimed and our collected data will become available to other Salt Marsh restoration projects around the state. The Discovery Center has a great view of the restoration effort, so we invite all our readers to stop by and take a look.