There’s an invasion plaguing the coastal waters of Southern California.

Waves of tiny interlopers spark havoc at fisheries, clog municipal water pipes and frustrate boaters who must dislodge buckets of sea crud.

They’ve altered our coastal regions’ ecosystems, endangered native fish and birthed such nasty problems as “swimmer’s itch.”

Accelerated in recent decades by international trade, invasive sea creatures have hitchhiked here in and alongside massive cargo vessels from around the globe.

Local officials admit they often don’t know enough about these oft-destructive invaders to halt their environmental takeovers or truly know to what extent the strategies they’ve launched against them are actually working.

But experts from such prestigious organizations as the Smithsonian Environment Research Center have vowed to gather the intelligence needed to rescue native species by studying the incoming hordes, comparing the myriad areas they’ve infiltrated and assessing whether anti-invasive methods and regulations already in place are effective.

“We still don’t know enough about these species,” said Brianna Tracy, a research biologist for the center, which has launched four years of monitoring of the waters along the nation’s largest seaport, the twin Long Beach and Los Angeles cargo complexes.

“It’s very difficult to put a dollar value on the ecosystem impacts,” said Edwin Grosholz, a professor at UC Davis and vice chairman of the Invasive Species Council of California. “They are still coming in, and it’s hard to tell whether we have reduced the influx.”

That’s why officials are calling on such teams as the Smithsonian’s crew to learn enough about such species to, with hope, stop them before it’s too late to save the native environment.

Clogging the pipes

An estimated 114 invasive species live in the bay around the Southern California ports. And that’s far less than the 300-plus varieties that thrive up the coast in San Francisco Bay, considered an “international hot spot.”

To the untrained eye, these foreign species don’t look much different from harmless sea algae or water snails. But they can be pernicious and costly.

The Metropolitan Water District of Southern California learned this firsthand.

The agency spends $3 million to $5 million annually trying to contain the quagga mussel, a fingernail-size species from Eastern Europe that landed a decade ago in aqueducts carrying water from the Colorado River into the Southern California basin.

The stubborn species is known to blanket the system’s pumps and cling to its pipes, clogging up the distribution system and choking the flow of fresh water.

Officials release chlorine once a year to sweep the tiny creatures from the system. It can clear the way for a while but can’t altogether rid the system of the pests for good. And that’s the conundrum with these creatures.

“If you don’t detect them early, there’s no chance of eradicating them,” Tracy said.

Back in the 1990s, Caulerpa taxifolia was found in a Carlsbad lagoon. Likely dumped from a home aquarium, the species went on to do enough damage to earn the nickname “killer algae.”

The hearty seaweed, native to tropical waters, can grow an inch a day and survive for days out of water. It covered the lagoon like a thicket and decimated the native populations in its path.

Authorities spent $7 million to, at last, get rid of it. And “it would be a lot more expensive today,” warned Steve Foss, senior environmental scientist who manages the marine invasive species program for the California Department of Fish and Wildlife.

Taking over

The findings of the Smithsonian should help the state, which is funding the project, craft and revise regulations to reduce invasive species.

For example, there are the “bilge-water rules.” Because many invasive species trekked here in the ballast water of cargo vessels from Asia, regulations were passed to dump ballast water 200 nautical miles off the coast.

Local officials hope such restrictions are helping to stave off their onslaught, but it’s unclear just how well they work.

Enter the Smithsonian team. Their research should help evaluate such efforts and more.

The team is scrutinizing highly trafficked commercial port areas as well as waters where noncommercial boats are more common.

In addition to the ports, scientists are studying nine other estuaries up and down the coast, including one near Newport Beach.

The research is a lot more complicated than counting fish, algae, crustaceans and other sea life.

“Sometimes it’s hard for the experts to identify these species,” Foss said. “It’s really tough because some look identical.”

Researchers at Moss Landing Marine Labs at San Jose State University will also be logging the creatures’ genes. There’s a huge empty database to fill. Only a fraction of the world’s underwater organisms have been recorded in such a way.

The world’s evolving climate is making such unwanted migrations easier, some experts fear.

Many of the creatures once believed to be native to Southern California are actually invaders, recent research has revealed. Amid climate change, they’ve established themselves in new homes where the water is growing warmer and more hospitable.

In California, scientists say they are seeing such a spread of species from south to north, as the temperature of frigid northern waters rises.

Invaded coastline

Some creatures threaten a gradual, homogenous ”whitewash” of more and more miles of shoreline each year.

This environmental infiltration not only threatens native creatures, but the ecological diversity of each region.

“We are homogenizing many of the bays and estuaries,” said Andy Chang, an ecologist who heads the Tiburon Branch of the Smithsonian’s Marine Invasions Lab. “It’s remarkable how many of these (invasive) species you are seeing over and over.”

As these species alter native ecosystems, they may ultimately threaten feeding sources. Experts fear nutritious “phytoplankton’ and other organisms are getting crowded out.

The U.S. Fish and Wildlife Service estimates more than 400 of the over 1,300 species listed under the Endangered Species Act are considered to be at risk because of invasive species.

Last year, the Metropolitan Water District suffered a new scare.

After the district launched its effort to clear away quagga mussels, it discovered a new wave of tiny shelled creatures in a different distribution system directing water from Northern California into Southern California’s homes and businesses, one previously untouched by the invaders.

Tapping its experience coping with the creatures, the district swiftly assessed its lines. Ultimately, the species weren’t found in large numbers.

“We may have dodged a bullet on that one,” Foss said.

The lesson: respond at the first sign of invaders. And respond quickly.

“One of the big questions is, is it a problem,” Grosholz said. “Often you don’t know it’s a problem until it’s a problem.”