TOKYO » The tiny Pacific nation of Palau, fighting a rising tide of illegal fishing in its waters, has set fire to four boats of Vietnamese caught poaching sea cucumbers and other marine life in its waters.

Palau’s president, Tommy Remengesau Jr., said the boats were burned Friday morning. He hopes to turn most of the island nation’s territorial waters into a national marine sanctuary, banning commercial fishing and exports apart from limited areas to be used by domestic fishermen and tourists.

"We wanted to send a very strong message. We will not tolerate any more these pirates who come and steal our resources," Remengesau said in a phone interview with The Associated Press from Washington, D.C., where he was visiting.

The country created the world’s first shark sanctuary in 2009, but until recently had only one patrol boat to help protect its great hammerheads, leopard sharks and more than 130 other species of shark and rays fighting extinction.

The four boats destroyed Friday were among 15 Palau authorities have caught fishing illegally in their waters since last year with loads of sharks and shark fins, lobsters, sea cucumbers and reef fish. Several of the boats that it seized, stripped of their fishing gear, are due to carry 77 crew members of the boats back to Vietnam.

Remengesau said that the stream of poachers showed that just stripping the rogue boats of their nets and confiscating their catches was not enough

"I think it’s necessary to burn the boats," he said.

Palau, about 600 miles miles east of the Philippines, is one of the world’s smallest countries, its 20,000 people scattered across a tropical archipelago of 250 islands that is considered a biodiversity hotspot. In 2012, its Rock Islands Southern Lagoon was named a UNESCO World Heritage site.

Driven by rising demand from China and elsewhere in Asia, overfishing threatens many species of fish. With 240,000 square miles of territorial waters, including its exclusive economic zone, or EEZ, extending 200 miles from its coastline, Palau is battling to prevent poaching of its sea life by fishermen from across southeast Asia.

Despite progress in tracing sources of fish sold to consumers, about a fifth of the global market for marine products caught and sold, or about $23.5 billion, is caught illegally.

Advances in telecommunications and vessel tracking technology have improved surveillance, but enforcing restrictions on unauthorized fishing is costly and difficult, especially given the many "pockets" of high seas in the area.

"There’s a lot of opportunity for illegal fishing and other transnational crime. It’s a challenge," said Seth Horstmeyer, campaigns director for The Pew Charitable Trusts’ Global Ocean Legacy program. High seas pockets, beyond the jurisdiction of any government, account for nearly two-thirds of all ocean areas.

From Palau to Japan is a vast expanse of seas that nobody controls and nobody owns, areas that serve as refuges for illegal fishing vessels.

The Vietnamese fishermen tend to prowl shallows seas and reefs in search of sea cucumbers and reef fish and then flee back into those deeper waters to evade capture, Horstmeyer said.

One way to counter that tactic is to create a "geofence" using vessel identification systems that could trigger alerts when vessels cross into national waters.

Nearby Indonesia also is taking harsher action, recently blowing up and sinking 41 foreign fishing vessels from China, Malaysia, the Philippines, Thailand and Vietnam, as a warning against poaching in the country’s waters.

In Hanoi, Foreign Ministry spokesman Le Hai Binh recently told reporters the government was seeking to protect the rights of the fishermen. He urged other governments to "render humanitarian treatment toward the Vietnamese fishing trawlers and fishermen on the basis of international law as well as humanitarian treatment toward fishermen who were in trouble at sea."

While burning and sinking such ships seems drastic, the International Tribunal for the Law of the Sea has backed such moves, ruling that countries can be held liable for not taking necessary measures to prevent illegal, unreported or unregulated, so-called IUU, fishing operations by their vessels in the waters of other countries.

In a report on IUU fishing last year, the Indonesia government outlined a slew of tactics used by poachers, including fake use of Indonesian flags on foreign vessels, forgery of documents and use of bogus fishing vessels using duplicate names and registration numbers of legitimate ships.

Poachers "go where the risk of being discovered is lowest, said Johanne Fischer, New Zealand-based executive secretary at the South Pacific Regional Fisheries Management Organization, which works on conservation and sustainable use of fishery resources in the South Pacific Ocean.

"Part of the problem is the mafia type of the thinking of the industry of just trying to make money. It’s human nature, whenever you have possibility to make money with illegal activities. It’s the same in the ocean."

As Palau’s plan for a national marine sanctuary moves through its legislature, other Pacific countries and territories are taking similar measures.

Britain is preparing to make the Pitcairn Islands, home to descendants of the mutineers from the HMS Bounty, the world’s largest continuous marine reserve at 322,000 square miles.

Last year, the U.S. government announced it was expanding protected areas in three areas — Johnston Atoll, Wake Atoll, and Jarvis Island —of the Pacific Remote Islands Marine National Monument to encompass about 405,000 square miles of non-contiguous sanctuaries.

As it gears up for stricter enforcement, Palau is consulting with Pew, Japan’s Sasakawa Peace Foundation and some foreign navies on ways to better police its waters using land-based radar, aerial surveillance and satellite identification systems.