MANILA, Philippines >> Pacific island nations and environmentalists raised an alarm Sunday over destructive fishing methods and overfishing that they say are threatening bigeye tuna — the fish popular among sushi lovers worldwide.

Palau fisheries official Nanette Malsol, who leads a bloc of Pacific island nations, said at the start of a weeklong tuna fisheries conference in Manila that large countries should cut back on fishing, curb the use of destructive fishing methods and respect fishing bans to allow tuna stocks to be replenished in the Pacific, which produces more than 60 percent of the world’s tuna catch.

The annual meeting of the Western and Central Pacific Fisheries Commission, which regulates commercial fishing in the vast expanse of waters from Indonesia to Hawaii, is to approve steps aimed at protecting the bigeye and other threatened tuna species, along with giant whale sharks. More than 600 delegates from about 40 Asian and Western countries, along with environmental activists, are attending.

Malsol said she expects heated debate. Proponents of the multibillion-dollar fishing industry have squared off with conservationists in the past over the best ways to protect the bigeye and other species without considerably setting back the lucrative business.

Bigeye and yellowfin tuna, which can grow to 8-9 feet (2.4-2.7 meters) long and weigh more than 450 pounds (200 kilograms), are not in immediate danger of being wiped out, but have been hit hard by overfishing. The fish are used mostly for steaks, and in the case of bigeye, sushi.

The fisheries business in the western and central Pacific region, estimated to be worth about $5 billion annually, has drawn increasing numbers of industrial fishing fleets, which have caused tuna stocks to fall since the 1960s.

“This week it’s up to the big fishing nations to show the world what they are going to do to cut overfishing of bigeye tuna,” Malsol said.

Repeated telephone calls and messages to industry officials seeking comment Sunday were not answered.

Many fleets are using so-called “fish aggregation devices” — various types of floats which are used to lure vast numbers of tuna. When schools of tuna have massed under the devices, fishing vessels alerted by sensors approach and scoop up their catch with giant nets.

Between 47,000 and 105,000 fish aggregation devices, made from bamboo, palm fronds, plastic or old nets, have been deployed worldwide to attract a wide variety of marine life. The method is used to catch nearly half of the world’s tuna and has contributed to the overfishing of bigeye tuna across the Pacific Ocean, according to the U.S.-based Pew Environment Group.

Aside from tuna, sea turtles, sharks and juvenile fish have often been caught and killed.

“The deployment of tens of thousands of drifting fish aggregating devices in the world’s oceans with little to no oversight is extremely worrisome,” said Amanda Nickson of the Pew Environment Group.

“The fishing industry is not currently required to account for its use of FADs. It is being allowed to gamble with the health of the ocean, and it is time for governments to require full accountability and management of this proliferating and risky fishing gear,” Nickson said.

Conservation efforts, however, have been tough to implement and have sparked disagreements.

Greepeace activists said they will submit evidence to the fisheries commission detailing violations of regional tuna fishing rules by Southeast Asian countries including allowing fishing vessels to operate on the high seas without permits and required observers onboard.

A decision by the fisheries commission to exempt the Philippines from purse seine fishing — an industrial technique in which a net is used to surround and capture schools of fish — in a large swath of the Pacific has sparked complaints from other nations.

The exemption was given to discourage Philippine fleets from fishing in territorial waters off the country’s eastern coast, which are known spawning grounds for tuna that later spread out to the Pacific.

Philippine Agriculture Secretary Proceso Alcala asked the fishing commission to extend the exemption, which he said started last October and would end in February next year.