Suddenly currency swings are back in the news again.

After a period of dollar strength, that contributed to record seafood imports of commodities like shrimp and salmon in 2016, the U.S. dollar has reversed course, and has fallen about 7 percent since January of this year against a composite of foreign currencies.

This kind of change in currency values can have a big impact on profitability for overseas exporters to the U.S.

Take lobster and Canadian snow crab for example. From May 1 until July 31, the Canadian dollar has strengthened from $1.35 to $1.25, a change of nearly 7.5 percent.

Geoff Irvine, executive director of the Lobster Council of Canada said, “A strong dollar is the last thing we want as exporters of Canadian seafood products. Our live and processed lobster products are generally priced in U.S. dollars and while some exporters are able to hedge … many remain at the mercy of changes to the value of the Canadian dollar that are out of their control.”

Canadian live and processed lobster exporters maintain inventory through periods of minimal fishing activity and therefore are subject to changes in the value of their inventory based on currency fluctuations, especially when they occur in such a short period of time.

Stewart Lamont, managing director of Tangier Lobster Co., a live lobster exporter in Nova Scotia, said, “Currency exchange is a key variable for international trade. On this one, the lobster industry lost badly.”

On behalf of the lobster processing sector, Jerry Amirault, president of the Nova Scotia/New Brunswick Lobster Processors Association, said, “This is hurting the lobster industry, the communities in which the plants operate and the whole Atlantic region.”

With a slow pace of landings this spring, lobster prices to harvesters have been at one of their highest levels in years, both in the U.S. and Canada. Now Canadian lobster companies have these sunk costs for their raw materials, and their market return is down 7 percent before any price changes.

And the seasonality of lobster pricing means that the lowest prices of the year will occur in the next four months. So the currency swing will be a significant blow to both live shippers, and to processors who have just begun to see a recovery in tail prices.

The same dynamic applies to snow crab. One of the biggest market questions is who is holding crab in inventory right now, as prices have jumped up as the season has ended. Normally snow crab prices rise in the months between August and December, as harvesting has ended and there is little new product on the market. But the market may be resisting some of these higher prices, and now the Canadian producers may have less leverage to make up for the dollar shortfall.

The dollar is also affecting shrimp. Import figures released this week show shrimp imports continuing to run ahead of last year’s record-setting pace, with shipments through the first half of the year up 1.6 percent.

But India and Ecuador, the two top suppliers to the U.S. market in 2017, face very different dollar pressures. Ecuador has always priced its shrimp in dollars, so a weaker U.S. dollar will not only not impact Ecuador shipments to the U.S., but will likely accelerate Ecuador’s shipments to Asia and Europe, who will in effect see lower prices.

But India, which is highly dependent on the U.S. market, will see the opposite effect. The rupee has strengthened against the dollar by about 6.6 percent since January, going from 68.1 rupees per dollar to 63.8, with forecasters saying it will go to 60 per dollar by the end of this year.

Here the reasons are mostly because of the strengthening of the Indian economy and favorable interest rates.

This has meant that Indian shrimp packers are feeling pressure to raise prices if possible, as their returns on dollar sales have fallen 6 percent to 7 percent.

The upshot is that many of the major imported seafood commodities will see pressure from producers to raise prices, at a time when markets are mostly moving in the other direction because of both seasonal and production factors.

For Alaska, the weaker dollar is a boon to exporters. It will help pollock sales recover in Europe, and will make sockeye less expensive. It will help with sales to Japan, although Japanese currency has been more stable against the U.S. dollar this year than many other currencies.

Most analysts expect the U.S. dollar to continue to weaken and so these trends with their positive and negative impacts on different seafood sectors will likely shape markets through the end of the year.