Invader Threatens Southland Waters

Alarmed at the discovery of a highly destructive species of aquatic plant life in a lagoon here, officials Wednesday announced plans to poison the fast-growing algae before it can spread and cause ruination along the entire Southern California coast.

The green algae, known scientifically as Caulerpa taxifolia, was found in the Agua Hedionda Lagoon, 35 miles north of San Diego. It is the first reported discovery of the species anywhere in North America.

The algae poses no direct health threat to humans but has caused massive damage to the ecosystem, fisheries and tourist economy in parts of the Mediterranean and Australia. The plant spreads along the bottom of lagoons and inlets, crowding out native vegetation like a lethal carpet of Astro Turf. It provides no nutrition for fish, which are repelled by its noxious taste.

Federal and state officials hope to kill the plant by sending divers out to inject repeated doses of chlorine under a tarp covering the half-acre patch of lagoon bottom where the plant has been located.

“Unless you control it very quickly, you lose the ability to control it at all,” said Bob Hoffman, Southern California environmental coordinator for the National Marine Fisheries Service.

Officials are concerned that if left unchecked, the plant could become as destructive and vexing to control as other great plant pests of the past, including the dread hydrilla, an aquatic weed that infests lakes, and the giant salvinia, a plant doing its best to choke off the All-American Canal in Imperial County.

“It could have a drastic impact on fishing, recreation and endangered species,” Hoffman said at a lagoon-side news conference. “It’s very bad news.”

The worst-case scenario, Hoffman said, could include a quarantine at Southern California ports, which could have a crippling impact on maritime commerce.

For all its nasty properties, the Caulerpa taxifolia is an attractive, fern-like plant.

“It’s beautiful,” said Greig B. Peters, environmental specialist with the California Regional Water Quality Control Board in San Diego. “Maybe that’s the reason people in the Mediterranean were lulled into not taking immediate action.”

Unwilling to be similarly deceived, officials here have roped off the half-acre patch of water near the shoreline and posted a 24-hour guard to keep the public away.

The rest of the 350-acre lagoon, a popular spot for canoe and Jet Ski enthusiasts, will remain open for use, although divers continue to check for further outbreaks. One of several lagoons that define the coastal region of Northern San Diego County, it is just east of a power plant owned by Cabrillo Power.

The algae, referred to by officials as an “alien marine species,” was found during routine monitoring done to assess the effectiveness of a program to plant eelgrass in the lagoon.

In the affected area, the algae already has displaced the eelgrass, which provides nutrition for California halibut, sand bass and perch.

Officials suspect that the algae invaded the lagoon after someone dumped a saltwater aquarium into a storm drain. They are concerned that the algae could be spread by fishing nets, boat anchors or Jet Skis.

Although the plant was banned for sale last year under the Federal Noxious Weed Act, it can still be purchased through the Internet, officials said.

The Mediterranean outbreak has been traced to an accidental release from the Oceanographic Museum of Monaco in the early 1980s. The plant has spread to about 10,000 acres off France, Spain, Monaco and Italy.

A single stem of the plant can grow to a length of nine feet and have up to 200 fronds that can rapidly spread the algae over a wide area.

The algae also can survive at relatively cool temperatures and at depths of 100 meters, assisting in its ability to spread quickly. Because of its ability to withstand colder temperatures better than other saltwater plants, officials fear that it could even spread to Northern California.

Worse yet, officials think that this strain may be an even more aggressive one than that found in Australia and the Mediterranean.

The algae coats everything in its way, using up oxygen and preventing fish from reaching the invertebrates and worms they eat.

The California Coastal Commission and the Army Corps of Engineers are expected to issue emergency permits to allow the poisoning effort in the eastern portion of the lagoon.

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Dangerous Algae

Invasive algae that overgrows and eliminates native seaweeds, seagrass reefs and other plant communities has been discovered in a San Diego County lagoon. The species was declared prohibited in 1999 under the federal Noxious Weed Act.

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Caulerpa taxifolia

Habitat: Native to tropical waters in the Caribbean and the Indopacific region, but a fast-growing clone has spread to the northwestern Mediterranean Sea and the waters off Sydney, Australia.

Use: Decorative plant for saltwater aquariums. Importing into U.S. is banned.

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Description: Stem length of more that nine feet with up to 200 fronds. Forms a blanket on any substrate.

Reproduction: Spreads through fragmentation--a piece can regenerate a new plant. Survives up to 10 days out of water. Most attempts to remove it have failed, often resulting in an even more rapid and vigorous regrowth.

Source: Times research