China’s island-building in the South China Sea is driving Asia-Pacific nations to seek the type of amphibious skills that U.S. Marines have honed over decades, the retiring commander of U.S. Marine Corps Forces, Pacific, said Friday.

Lt. Gen. John A. Toolan said, “If you look at what’s going on in the South China Sea and all the claims on land and islands, and the fact that there’s a lot of reclamation of land going on — they are putting together acres and acres and acres of airfields and sites for (surface-to-air) missiles and all kinds of things.”

It’s important that the United States have the necessary military capability in place “if those islands should turn against us,” Toolan said, referencing the Spratly and Paracel chains. Other nations besides China have vested interests in the region as well.

“And amphibious is the way to handle islands,” Toolan said.

Toolan turned over command of Marine Corps Forces, Pacific, the largest field command in the Corps with about 86,000 Marines, to Lt. Gen. David H. Berger during a waterfront ceremony at Marine Corps Base Hawaii at Kaneohe Bay. Those Marines are in Hawaii, California, Japan, South Korea, Guam, Australia and Arizona, the command said.

Adm. Harry B. Harris Jr., head of U.S. Pacific Command, lauded Toolan as “one of the great leaders in the Marine Corps,” while calling Berger a “combat- tested leader” for his experience as a regimental combat team leader in Iraq and commanding general of the 1st Marine Division in Afghanistan.

Berger assumed command of the I Marine Expeditionary Force in California in July 2014. According to its Facebook page, I MEF “provides the Marine Corps a globally responsive, expeditionary, and fully scalable Marine Air Ground Task Force, capable of generating, deploying, and employing ready forces and formations for crisis response, forward presence, major combat operations, and campaigns.”

Hawaii’s four four-star generals and admirals attended the command change, while more than 400 Marine noncommissioned officers — the backbone of the Corps — stood in formation. An Osprey tilt-rotor aircraft was flanked by CH-53E Super Stallion helicopters and M777 howitzers for the ceremony.

The Corps will probably keep about 20,000 Marines west of the international date line, Toolan told reporters afterward. But it’s moving Pacific Marines around — with about 10,000 relocating from Okinawa to Guam, Australia and Hawaii.

“We see troops moving to Guam around 2021,” Toolan said. “We see forces in Australia potentially increasing over the next couple of years.”

In 2023 “we’ll start to see some movement” of about 2,700 Marines from Japan to Hawaii, Toolan said.

Up to 2,500 Marines eventually will rotate through Australia on temporary deployments as they do now in lesser numbers. They will be based on and also rotate through Guam, and the extra Hawaii Marines will be based here, the Corps said.

Marine Forces Pacific conducted the second annual Amphibious Leaders Symposium in San Diego in July with 22 partner and allied nations participating from the Indo-Asia-Pacific region. South Korea, Japan and Australia are among nations increasing their seaborne abilities, which are also important for humanitarian assistance in the event of a natural disaster.

Other nations are “figuring out how they can best contribute and interoperate with (U.S. Marines),” Toolan said. “It’s paying huge benefits for us, and in the long run it will help us give them areas to focus on while we focus on the high end (of operations).”

Toolan said the relationship with the Philippines “has really grown.” The Philippines is “key terrain,” and strides have been made to help the country build its army to respond to territorial defense as well as deal with internal security issues, Toolan said.

As is the case with most major command changes, the focus was on Toolan as the departing leader. Berger acknowledged the momentum Toolan created. “I need to make sure that that doesn’t stop,” Berger said.

After 40 years as a Marine officer, Toolan is retiring, and promised to spend more time with his wife, Helen, who is from Texas.

“This is our last rodeo in uniform,” he said in his remarks. “Well, maybe not the last rodeo. She’s taking this Yankee to Texas — so I’ll have to figure out how to walk in cowboy boots.”