An international fisheries commission adopted Friday looser regulations on tropical tuna fishing in the western and central Pacific Ocean, following scientific studies suggesting that certain tuna varieties in the region are not overfished.

Member and participating countries under the Western and Central Pacific Fisheries Commission agreed on a measure that will increase the catch limit on bigeye tuna as well as shorten the closure period of fish aggregating devices on the high seas.

Shigeta Oda, head of the Japanese delegation, said the allowable catch limit was increased by about 8 percent on average, while the closure period was reduced to five months from 12.

Rhea Moss-Christian, chairwoman of the WCPFC, said that the measure is a result of a long process of consultation among the countries throughout their five-day conference held in Manila.

Speaking on the sidelines after the meeting, Moss-Christian said the regulations cater to members' needs in terms of economic development while allowing fishing mortality to be maintained at "appropriate levels."

She added that the new regulations are based on the latest assessment of tuna stocks in the region.

"There is new science to the bigeye stock, and the science shows that the bigeye stock is not as low as we have previously thought. It is in a much better state," she said.

In Tokyo, fisheries minister Ken Saito called the agreement a "major advance" and said Japan would "firmly lead the way" in domestic resources management.

"There remain various difficulties such as stationary nets, so we will hold in-depth deliberations," he added, speaking after a Cabinet meeting.

According to the latest stock assessment made by the commission's scientific committee, bigeye, skipjack, yellowfin and the South Pacific albacore tuna varieties are not overfished and overfishing is not occurring.

However, the committee has suggested reducing the catches of other species of fish such as the Southwest Pacific striped marlin, the Western and Central North Pacific striped marlin, the silky shark and the oceanic white tip shark.

Oda said Japan was initially against the easing of the regulations on bigeye tuna, arguing that the improvement of the stock for this tuna variety meant that current measures are working and thus must be maintained.

The Japanese official added that it would have been ideal to wait until the next stock assessment to reinforce the findings of the scientific committee that the bigeye tuna variety is not in danger of being overfished.

However, Oda said this was a minority view among the countries in the commission and most of the support only came from non-government agencies attending as observers.

Still, Wez Norris, deputy director general of the Pacific Islands Forum Fisheries Agency, called the new measure a big achievement for the tuna commission despite it falling short of the ideal target when it comes to tuna conservation in the Western and Central Pacific region.

"While it doesn't meet exactly what we were after as Pacific island countries, it is a pretty good measure to carry the stock conservation forward," Norris said, adding that the meetings also produced other positive results, including the port state measures agreed upon by the members.

"That's a big one because that will improve the cooperation between members as they request inspections in port and dealing with illegal fishing risks," he said.

The Western and Central Pacific Ocean is a major source of the world's tuna catch, accounting for about 2.8 million metric tons or 56 percent of the global tuna catch in 2016.

The tuna commission has 26 member countries as well as seven participating territories and seven non-member states, making it a major avenue of fishery policy creation in the region.