PORTLAND — It may sound fishy, but a Maine fish dealer says importing cod from Russia will have benefits in Russia and North America.

Resource Trading Co. of Portland recently imported 150 tons of Russian cod into Rockland to supplement dwindling supplies in waters off New England and eastern Canada.

Processors in Maine and Canada hope the new supply will help them keep markets that might otherwise be lost. The venture provides high prices to the Russians, who can then spend money on lower-priced herring, a popular food in Russia.

“They can turn one ton of codfish into about 10 tons of herring,” said Spencer Fuller, a partner of Resource Trading.

The deal is the first in which large amounts of Atlantic cod have been imported from Russia.

“It seems like this is going to be a new import — which is understandable, because they have the cod,” said Milan Kravanja, a Russian fisheries specialist with the National Marine Fisheries Service.

Once plentiful in waters off New England and Maritime Canada, cod stocks have dwindled and the catch has been restricted by the Canadian government. A complete ban on cod fishing in Newfoundland earlier this year has left fish plants idle and hundreds of employees out of work.

New England processors are affected because they buy some of their cod from Canada. Plants in both countries process cod into fish sticks, fillets and other frozen food.

Russian fishing boats catch cod in the Barents Sea, north of Russia near the Arctic Circle. The fish is gutted, frozen and loaded onto transport ships that have traditionally returned to Russia or hauled the catch to European markets.

But demand for cod has fallen in Europe, while it remains high in New England and Canada.

For several years, Resource Trading has helped Maine fishermen sell menhaden and herring to Russian fish-processing vessels off the Maine coast. This is the company’s first move into importing Russian fish.

The first shipment of Russian fish arrived in Rockland in late September. A second shipment of between 700 and 1,000 tons is scheduled to arrive at a Canadian port later this month.

Fuller said future shipments will probably arrive monthly in Maine and Canada.