The Midnight Express, a 900-horsepower U.S. Customs and Border Protection boat, speeds  across San Diego Bay. The crew's mission is to intercept smugglers who try to bring drugs and immigrants into the U.S. along the coast.

With tougher enforcement and new barriers rising along the U.S.-Mexico border, many smugglers are taking to the sea to move drugs and immigrants.

By Richard Marosi

Reporting from Popotla, Mexico — Nallely and Heriberto Salgado boarded the Mexican fishing skiff bobbing off the Baja California coast last week and watched warily in the moonlight as 19 other people squeezed onto the vessel designed to carry no more than a dozen.

A smuggler piloting the 25-foot boat promised a short ride before landing on a beach in San Diego.

But 12 hours later, the Salgados were still being lashed with sea spray. The thick fog had burned off, leaving a panorama of brilliant blue, with no land in sight.

"We saw only ocean all around us," said Nallely Salgado. "And we were running out of gas."

With tougher enforcement and new barriers rising on land along the U.S.-Mexico border, many would-be immigrants like the ones crowded aboard the Tiburon are taking to the sea.

More than 310 people have been arrested on suspected smuggling boats since October 2007, more than triple the number from the previous 18-month time period. Marijuana seizures have also surged, with more than 29 tons seized in the same time frame, a more than tenfold rise from the previous period.

The increase in maritime smuggling has raised concerns with U.S. officials that Mexican trafficking groups are moving to exploit a perceived weakness in border defenses. Though sea journeys are risky, smugglers appear increasingly willing to take their chances on evading the handful of U.S. boats that patrol an area roughly twice the size of Los Angeles.

"This is a fast boat," said Keley Hill, San Diego marine operations director for U.S. Customs and Border Protection, as he piloted the 39-foot Interceptor outside San Diego Harbor. "But it's a big ocean."

Some boats slip through. In recent months, several abandoned vessels, with life jackets scattered nearby, have been discovered on beaches along the San Diego County coast. And last week, eight bales of marijuana weighing 400 pounds floated ashore at a Del Mar beach.

Immigrants once destined for arduous -- and increasingly unsuccessful -- mountain or desert crossings are now shuttled by smuggling groups to fishing villages and isolated beaches south of Tijuana. They pay as much as $4,000 for the crossing, according to Immigration and Customs Enforcement.

Some immigrants have told U.S. authorities that they have departed from the run-down village of Popotla, near Rosarito Beach, where dozens of brightly colored vessels sit on a small beach lined with shanties and seafood stands.

The settlement is filled with out-of-work fishermen, impoverished families and some criminal deportees from California.

"They're not leaving from here . . . too many people can see them," said one restaurant owner, who declined to give his name out of concern for his safety. "But there are lots of beaches nearby where nobody would notice."

Smuggling boats often zip toward the first beach inside California, typically Imperial Beach or Silver Strand State Beach. Others motor across the strait to the Coronado Islands, where they switch vessels before heading farther north toward marinas or beaches at Mission Beach, Del Mar or Torrey Pines State Beach.

Responsibility for intercepting the boats lies with the U.S. Coast Guard and U.S. Customs and Border Protection, which together have a fleet of about 10 vessels along with at least three helicopters for air support.

The smugglers generally use open-topped Mexican fishing boats called pangas. The wooden or fiberglass vessels are hard to detect on radar, especially in high seas. If spotted, many boat operators spin around and head back to Mexico, often successfully. A panga loaded with 25 people can outrun an 87-foot, diesel-engine cutter, say Coast Guard officers.

Some authorities say staffing levels are too low and the fleet isn't large enough.

On a typical night, only two vessels patrol the coastal waters, according to the Coast Guard.

Making matters worse is what some federal authorities consider lax enforcement of customs laws by U.S. Customs and Border Protection.

"If you know a boat has cleared customs, that leaves one less boat you have to pay attention to," said one federal maritime agent who spoke on condition of anonymity because he is not authorized to speak to the media.

Most boats coming from Mexico are supposed to clear customs, but in practice some don't because the office at Shelter Island in San Diego Bay is not staffed, say boaters and federal authorities. Boaters are supposed to summon customs agents to the office from a phone at the dock, but the slow procedure discourages many from reporting.

Vince Bond, a customs spokesman, said staffing shortages prevent the agency from staffing the office full time.

Smugglers -- some of them U.S. citizens -- take greater risks to get their cargo of people and drugs through, say federal authorities. Boats are often dangerously overcrowded. Immigrants sometimes are not provided with life vests. And they aren't permitted to bring backpacks with food and water.

Many boats are dilapidated and barely seaworthy. Last year, one vessel lost power 20 miles out to sea and drifted for two days with 15 people aboard. The Coast Guard arrived just in time; the boat was sinking.

Nallely and Heriberto Salgado, from Michoacan, said they were told a sea crossing would be easier than their past treks north, which included walking through the Arizona desert and crawling through fig fields into California.

Nallely Salgado, who is three months pregnant, said the smugglers told them to keep their heads down during much of their 15-hour journey. People started getting sick. Some vomited. One woman fainted, she said.

Noting that the pilot seemed lost, some migrants started to say the rosary. When a private boat cruised by, they yelled for help. The Coast Guard cutter Haddock soon arrived.

The boat had drifted 22 miles off the San Diego County coast.

When the passenger-laden Haddock arrived at the dock, Salgado said, she crossed herself and thanked the officers. She was returned to Mexico with her husband.

"Touching land was like being born again," she said.

richard.marosi@latimes.com