NEW YORK/MONTREAL (Reuters) - The U.S.-China trade war has triggered a seafood supply chain shake-up, with U.S. importers scrambling to stockpile frozen Chinese squid and tilapia ahead of looming price increases while Canada exports more lobsters to China.

A fishmonger places a Canadian lobster into a display tank at St. Lawrence Market South in Toronto, Ontario, Canada September 27, 2018. Picture taken September 27, 2018. REUTERS/Chris Helgren

A series of retaliatory tariffs between Beijing and Washington has led to a shift in global trade, creating winners and losers in sales of commodities from soya to seafood to pork.

About $3 billion worth of Chinese seafood imported into the United States is now subject to a 10 percent tariff that began this week, with the levy rising to 25 percent on Jan. 1. In July, China imposed a 25 percent tariff on U.S. seafood, hitting lobster, a delicacy for the Asian country’s burgeoning middle class.

As a result, Chinese demand for lobster from Canada has increased, with airports in the country’s eastern provinces adding cargo flights to accommodate higher exports.

At Halifax Stanfield International Airport, total cargo soared 42 percent in July, and 55 percent in August, compared with the same months a year earlier, fueled by Chinese demand for seafood, said Glen Boone, the airport’s director of cargo and real estate.

Canadian shipments of live or fresh lobster to China nearly doubled to 1.25 million kilograms (2.76 million lbs) in July, their highest level in at least six years, according to data from Statistics Canada. In 2017, Canada exported C$174.6 million ($134.06 million) worth of live or fresh lobster to China.

Stewart Lamont, managing director of exporter Tangier Lobster in Nova Scotia, said his Chinese sales are up 30 percent since July on an annual basis.

“The tariff factor has really redirected business to Canada,” he said.

For U.S. seafood importers, alternatives are pricier and more difficult to source.

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U.S. companies stocked up on Chinese seafood before the tariffs were imposed. But China is the source of much of the seafood found in low-cost frozen products sold by mass discounters such as Walmart Inc WMT.N, and stockpiles could soon be running low.

U.S. importers bought 6 percent more frozen tilapia from China, the biggest seafood import from the country, by dollar value in June and July of 2018 compared to the same months in 2017, according to the latest IHS Markit data available.

Imports of frozen salmon, another major Chinese import, jumped 20 percent in dollar value.

Pacific American Fish Company Inc imported about 20 percent more scallops and calamari in recent months to stock up before the new duties go into place, said Chief Executive Peter Huh. The seafood importer and distributor may add to stockpiles to bypass the looming additional 15 percent tariff coming next year, he said.

“That’s the only option we have,” said Huh, explaining why he hoarded higher-value products to maximize his savings.

Four other seafood importers said they were also bulking up their purchases ahead of time. Jim Heston of the Great Fish Company said the Winter Haven, Florida, importer added to its inventory to meet demand from customers who hoped to buy early fearing the new costs.

The tariff dispute has also delivered some supply-chain surprises, with increasing Canadian demand for lobster from the state of Maine, the biggest U.S. harvester of the crustaceans, according to industry groups, wholesalers and exporters on both sides of the border.

Stephanie Nadeau, owner of The Lobster Co, a Maine wholesale distributor, has seen a 40 percent drop in her overall sales in September as Chinese buyers look to Canada to satisfy its demand for the crustacean.

Yet prices remain stable in Maine for lobster harvesters, she said, because of demand from north of the border.

“The Canadians have stepped in,” Nadeau said.