Tinned fish has become a global phenomenon. What began as a pandemic-era pantry staple has evolved into a dining trend, with restaurants across the United States serving sardines, mackerel, and anchovies straight from the can. Domestic sales of shelf-stable seafood climbed from $2.3 billion in 2018 to over $2.7 billion in 2024, reflecting a sustained appetite for convenience and flavor. Sardines, in particular, have overtaken salmon as the second-most popular tinned fish, trailing only tuna. Grubhub reported that orders of tinned fish tripled in 2025. The global market reached roughly $10.24 billion in 2024 and is projected to hit $17.97 billion by 2034.

Yet the supply behind this growing demand is shrinking fast. Morocco, the world's top sardine supplier, experienced a staggering 46% decline in fish landings between 2022 and 2024. The reasons are interconnected. Sardines are highly sensitive to water temperature. As climate change warms the oceans, these fish move toward cooler, more distant waters. Fishermen who once worked familiar routes near the coast now must travel farther to find them. At the same time, the war in Iran has effectively shut down the Strait of Hormuz, a chokepoint through which one-fifth of the global oil supply normally passes. That disruption has driven up fuel costs, making those longer journeys even more expensive. The result: boats are bringing back almost half the quantity they used to.

Rashid Sumaila, a professor and Canada Research Chair in interdisciplinary ocean and fisheries economics at the University of British Columbia, has studied how fisheries navigate geopolitical forces. He told Fortune that the combination of climate stress and fuel price shocks is unprecedented: "Sardines are very sensitive to climate change, and we know it here on the Pacific coast. When it's warm, sardines move from Mexico through the U.S., and Canadians see more sardines. They follow the temperature." He observed the same pattern in Morocco and noted that on a trip to Portugal this summer, the temperature was still 34 degrees Celsius at 2 a.m. "Some of that 45% drop is partly climate change, and partly overfishing, and other things happening to the ocean. There's just so much. You have pollution, plastic. Stresses upon stresses."

The Iran war adds a second layer of pressure. While Iran's own waters are not a major sardine source, the conflict reaches Moroccan boats through fuel prices. "The Iran war doesn't quite impact this directly," Sumaila said, "but indirectly it does, because prices are going up. The price of fishing, the vessels, the energy. It's crazy." Since the conflict began, Brent crude surged 10% to 13% after the Strait of Hormuz effectively closed to shipping this spring—an event the International Energy Agency called the largest oil-supply disruption in history. Sumaila heard the same complaint from Thai fishermen, and from those in Africa and the Pacific Islands. "You can imagine Moroccan fishers feeling it too," he said.

The two pressures compound each other in a dangerous feedback loop. As sardines shift toward cooler water further from shore, fishermen must travel longer distances exactly when fuel becomes more expensive and the catch becomes less certain. "It's more risky," Sumaila said. "Insurance payments, security for people. The combination is really quite scary." He added, "It's like we're facing a double whammy."

The crisis is also reshaping how Morocco sells its catch. Frozen sardine exports have fallen from about 70% of the country's small open-sea fish exports in 2020 to roughly 23% in 2025, even before the war began. "Climate change is a factor," Sumaila said. "The war is going to affect it too, because all the freezing is energy, and energy prices are going up while the sources are being reduced."

Consumers will feel the pain at the grocery store. Sumaila's research on Canadian seafood spending shows that prices are rising while availability shrinks. "This isn't only the fish we catch in Canada. It's fish coming from all over the world. All of it gets affected. The price dynamics show up in people's household budgets." He noted that affordability pressure is hitting wealthier nations too: "I don't go to any meeting these days where somebody isn't talking about the cost of groceries."

Government fuel subsidies make the underlying problem worse. Sumaila's team estimates global fisheries subsidies at $35.4 billion in 2018, with $22.2 billion classified as capacity-enhancing—subsidies that fuel overfishing, shrinking fish populations further and forcing boats to travel even farther for a smaller catch. He jokes, "A fish called subsidies," referencing the film "A Fish Called Wanda." "A third of your fish is actually subsidized and illegally caught."

Outside Morocco, Portugal and Spain are also grappling with the consequences. Portugal's 2026 sardine season reopened in May with a national catch limit of 33,446 tonnes, nearly 1,000 tonnes fewer than the previous year. Portugal closed its purse-seine sardine fishery for the final weeks of 2025 after its fleet worked through roughly two-thirds of the combined Portugal-Spain quota. Spain's 2026 quota came in nearly 3% lower than the prior year, yet sardines sold for an average of 1.50 euros a kilogram, 50 cents above 2024 levels. To combat the "less fish, more money" scenario, Morocco imposed an export ban on frozen sardines to protect domestic supply and stabilize prices. Sumaila had little hope for such measures, citing trade fights between the U.S. and Canada: "When you ban fish, maybe in the short term you have some relief. But that triggers a lot of other things you might not even perceive when you do it. You get a counter reaction, and a counter reaction to that."

Most critically, sardines are a primary food source for lower-income individuals. "When you shut off these consequences, you're affecting small-scale people," Sumaila said, referencing the emigration of fishermen from Morocco to Portugal. "People move. And then you have immigration. Where is this coming from? It's coming from things like the war in Iran, too."