Russia’s newly approved ban on a scorched-earth form of ocean fishing is driven by environmental interests, not international politics, analysts and activists have said.

An investigation by The Japan Times found no evidence to support fears in Japan that the drift net fishing ban is wholly or even partly politically motivated in the wake of Tokyo’s sanctions on Moscow over its actions in Ukraine. Interviews with experts and statements by Russian officials point instead to the growing influence of the environmental lobby in the country.

“Our Japanese partners understand that this is not in the slightest bit aimed at Japan,” Valentina Matviyenko, speaker in the upper house of Russia’s parliament, said in recorded comments as lawmakers approved the ban. “It does not reduce the catch quotas for Japanese fishermen. They are just going to have to fish in a civilized way.”

The Fisheries Agency says that Japan’s catches via drift net fishing in Russian waters totaled about 6,400 tons in 2014, and that it is concerned the ban will greatly affect Hokkaido’s economy.

Foreign Minister Fumio Kishida on Wednesday called the ban “extremely regrettable.”

However, a Moscow-based political analyst has discounted Japan’s concerns, saying that environmentalists had won the day.

“Definitely there was some balance of ‘Who’s going to lose?’ and I honestly don’t think that the Japanese fishermen came on top of all these considerations,” said political analyst Alexander Gabuev of the Carnegie Moscow Center, a think tank. “This more reflects the change in domestic lobbying-group power structure.”

On Wednesday, Russian President Vladimir Putin signed an amendment to a fisheries law that bans the use of large-scale drift nets to catch fish that head to rivers to breed. The prohibition includes the kilometers-long nets used by Japanese and Russian vessels to snare hundreds of tons of salmon every year. It affects all waters within Russia’s exclusive economic zone — up to 370 km offshore — and will take effect from Jan. 1.

“WWF Russia has long called for this initiative,” said Yurii Kislyak, Worldwide Fund for Nature spokesman in the eastern city of Petropavlovsk-Kamchatskiy. “It seems there were a range of factors behind its obligingly swift passage, including assessments by state auditors of threats and financial loss.”

Something that Japan may not realize, he said, is that Russian fishing companies will suffer equally.

“If a law on nature conservation is unbeneficial for international relations, that’s a pretty normal result,” he said.

A WWF position paper released as part of its lobbying for the ban claims drift nets cause serious collateral catches that threaten entire animal populations. Several meters deep, the nets are suspended from floats and can be many kilometers long.

“Studies show that Russian and Japanese drift-net fishing cause significant damage to populations of marine birds and mammals. Especially significant loss occurs in the Bering Sea,” the document says.

Many nations worldwide maintain partial or total bans on large-scale drift net use, including the United States and the European Union.

The trend gained momentum following a United Nations resolution in 1990, said biologist Andrew Fischer of the Institute for Marine and Antarctic Studies at the University of Tasmania.

“That resolution . . . really painted a negative picture of this kind of fishing,” he said.

Fischer said he spent three months on a drift net boat in 1990, where he witnessed significant unintended bycatch. The South Korean vessel he served on as a scientific observer was catching neon flying squid and, like many fishing boats, was unequipped to handle other species hauled in.

“Some days we’d run into a school of tuna, albacore tuna, which is a very prized catch. But they didn’t keep it,” he said. “There’d be thousands of tuna that would be dumped overboard. And they were dead for the most part.”

Fischer said he also witnessed birds and mammals such as Dall’s porpoises and Pacific white-sided dolphins getting snared in the mesh and drowning. Being mammals, they died after being held under and deprived of air.

“Every net essentially came up with something. Mostly it would be these albatross species, a lot of shark.”

Russia’s ban does not prevent Japanese vessels from continuing to fish for salmon, but operators will have to invest in new equipment.

“It can be tens of thousands of dollars per boat,” Fischer said, cautioning that changes of this kind can cut deeply into fishing communities. “The social element is more difficult to tackle than the financial one, I think.

“There’s fewer and fewer fish to catch and less and less boats are essentially needed, and there’s going to have to be a fundamental switch for a lot of these fishermen who have been fishing for generations.”

Reached by phone, several Russian fishing operators in Kamchatka and Sakhalin were either unavailable for comment or said they do not operate drift nets.

Japanese fishermen operate in Russian waters under a 1985 Soviet-Japanese interparliamentary agreement. They can fish in a wide stretch from Sakhalin island to the Bering Strait, with the catch amounts set annually by quota.

“That will still remain, and Minister for the Development of the Far East Aleksandr Galushka said recently that Russia is in a good will to negotiate with the Japanese side on how to compensate on possible losses,” said the Carnegie center’s Gabuev. “Basically, they are about to renegotiate some terms. Let’s see what forms it will take.”