Guam’s surfers fret about the impact of a $15 billion defense buildup on their island.

Willi C. Byerly is Guam’s unofficial steward of surf. I first encountered the lanky, tanned 57-year-old waterman leaning against a coconut tree, squinting through raindrops at an increasingly crowded break foaming just beyond the jetty of the boat basin downtown in the capital of Hagåtña.

After I introduced myself, he crossed his arms and said, “You’re not from Surfer magazine, are you? We don’t want any pros and their photo shoots around here. There’s barely enough waves for the locals.” Aside from flat water, nothing peeves Byerly, the head of a local surfer association, more than a mobbed lineup. When I said I’m writing about the U.S. military’s plans for the island, he responded, “It’s gonna be hell out here. Like too many rats in a cage.”

The military is moving ahead with a $15 billion expansion of its facilities that promises to transform this tiny American territory in the western Pacific. New planes, ships, artillery ranges, and more are all on the way. The most talked-about aspect of what’s known as “the buildup” is the pending arrival of 8,000 U.S. marines from Okinawa, Japan. The incoming service members plus their families and the accompanying civilian workforce will swell Guam’s population of 170,000 by 15 to 30 percent by 2014.

A local quip holds that the 212-square-mile island is already nothing more than “an oversized aircraft carrier” for the military, which owns a third of Guam. It’s no exaggeration to say that every Guamanian either has some military service or has a close friend or relative who does. Of the states and territories, Guam has among the highest per capita participation and death rates in the Iraq and Afghanistan wars. The eagerness to enlist is partly an extended expression of gratitude to the United States for liberating Guam from a brutal Japanese occupation during World War II. But it also points to a shortage of alternative career paths, and doesn’t amount to an unequivocal embrace of all things military.

“These guys are taking jujitsu courses, getting ready to defend their break,” Byerly said, jutting his chin at the distant silhouettes on the sea. He suggested I check out the martial-arts gyms to see for myself. As if on cue, the muscled owner of the Purebred Brazilian Jiu Jitsu Academy, Stephen Roberto, rolled up to the beach park in a red pickup. Roberto agreed with Byerly that tension is likely once the additional marines arrive, but overall he’s more optimistic.

“The buildup will give Guam more importance in the U.S.’s eyes, bring more jobs, and improve the economy,” he said. Roberto’s advice to the new marines: “They should come off-base and try to understand the culture. Just don’t be the loudest person in the bar.”

Guam’s politicians, academics, indigenous activists, and even a few business owners share the same concerns about overcrowding and potential lack of respect for the island and its people. Still, many of them are maneuvering for as much federal money as possible. Inside the one-story territorial legislature, about a block from a thriving banana grove, Senator Judith Guthertz, who chairs the buildup committee, laid out her wish list: hundreds of millions in federal funding for upgrades to roads, utilities, schools, and the port; guaranteed employment for locals; assurance that no harm will come to the tourism industry or to Guam’s indigenous Chamorro culture; and no incidents that mirror the well-publicized rape of a Japanese schoolgirl by American servicemen on Okinawa. She also wouldn’t mind voting powers for the island’s lone representative in Congress. “We don’t want to be treated like a 21st-century colony,” Guthertz told me. “We support the buildup, as long as it’s a win-win for Guam and the military.”

I asked Byerly if there are any concessions a wave-loving marine could make to avoid a confrontation à la the movie North Shore, in which a mainland surfer clashes with protective locals at Oahu’s surf mecca. “If they bring down a case of Bud and grovel a little,” he laughed, “that might work.”