El Niño Is Already Wreaking Havoc on Pacific Fisheries

We’re not even one month into “super” El Niño, the natural Pacific weather pattern characterized by warmer-than-average sea surface temperatures, and fisheries around the world are already getting scrambled.

In Peru, government officials have effectively canceled the fishing season for anchovies, one of the country’s most important exports and a leading source of fish oil and animal feed globally. The Indian government is preparing for a season of smaller, less plentiful Indian mackerel. Meanwhile, in Southern California, recreational and commercial fishers have reported some of the most successful months of tuna fishing they’ve ever seen.

The divergent situations show how El Niño can create winners and losers across the fishing industry, decimating some species while making others easier to catch. For fishers, the result is instability, with many forced to consider seasonal diversification. And consumers can expect fluctuations in the price of key fish products.

“People are worried,” said Juan Carlos Sueiro, an economist and fisheries director for the nonprofit Oceana Peru. As climate change is expected to drive more frequent, stronger El Niños, “our vulnerability is increasing.”

El Niño is a weather phenomenon that happens every two to seven years in the tropical Pacific Ocean. It was named by Peruvian fishers who, hundreds of years ago, noticed periodic fluctuations in their catches, with huge declines occurring every few years around Christmas. They called it El Niño, after the baby Jesus.

The reason it has such disparate impacts on different fisheries has to do with the way it moves around ocean water.

Under normal conditions, trade winds blowing west along the equator move warm water from South America toward Asia. This causes cold, nutrient-dense water to rise up from the depths, a process known as “upwelling” that encourages the growth of tiny algae near the ocean’s surface. During an El Niño, however, weakening trade winds slow or even stop this upwelling. Less algae at the surface means species that depend on it, like anchovies, are forced to search for grub in deeper waters. Not only does this make the fish harder to catch, it can also stress and shrink their populations.

At the same time, those ocean dynamics can boost other fisheries. El Niño often sees warm-water species like the skipjack tuna straying toward coastal waters of the Americas, where temperatures would normally be too frigid for them. Nearer to the shore, these species become easier to catch.

Both of these dynamics affect Peru, where El Niños of the past have both wiped out the country’s anchoveta fishery—the largest single-species fishery in the world—and increased the availability of shrimp, scallops, dolphinfish, and tuna. This spring and summer, coastal El Niño conditions have already strained the country’s anchovies, prompting the government to issue an indefinite ban on fishing for them during the April-to-July season so their populations don’t fall even further. Humberto Speziani, a Peruvian industrial fishing adviser and former director of the International Marine Ingredients Organization, said vessels equipped with sonar technology have been locating anchovies more than 100 meters below the sea surface. Even if commercial fishers were trying to catch those anchovies, they likely couldn’t—that’s twice the depth that’s reachable using normal purse seine fishing nets.

Seafood prices are liable to change, too, due to El Niño’s milder impacts outside the Pacific Ocean. Wild salmon, for example, can get so skinny from a lack of food during El Niño that they’re dubbed “snakes;” their decline in North American coastal waters can lead to higher ex-vessel prices—that fishers receive at the dock—that are then passed down to retail and restaurant customers. And in local Peruvian markets, prices for jack mackerel and corvina have already reportedly doubled, prompting families to buy more chicken instead. Sueiro said the opposite may happen with species like shrimp, whose populations have boomed during past El Niños.

One demographic that is likely to benefit from El Niño is Southern California fishers, who call the weather phenomenon a “special treat” due to higher-than-normal catches of bluefin tuna, swordfish, blue marlin, and other species that usually stay closer to the equator. Even before El Niño was officially declared in June, SoCal’s recreational anglers and commercial fishers were celebrating “unprecedented” bluefin tuna yields; one fishing tracker suggests that nearly 300,000 more of the fish were caught off the California coast during the first half of the year, compared to the same period last year.

“We’ve got yellowfin, we’ve got bluefin, yellowtail, and dorado. What else can you ask for?” the manager of one San Diego-based sportsfishing company said on YouTube at the end of April. “It’s not even May, and fishing’s been red-hot.”

Although artisanal fishers in South America often catch more of these species, too, they’re unlikely to fully offset economic losses wrought by El Niño. For one, high winds associated with the weather phenomenon can frustrate shipping vessels, making it harder to reel in additional species. And heavy rainfall can damage onshore infrastructure needed to process marine animals and take them to market.

El Niño-related shifts in fish migration can impact more than fishing economies. High ocean temperatures associated with the weather phenomenon can decimate coral reefs and the species that call them home. They can also cause kelp to deteriorate faster, reducing the amount of underwater oxygen available to maintain healthy ecosystems. And there’s been some research to suggest that shifting fish populations can escalate geopolitical conflict, as vessels stray into other countries’ economic zones.

Arnaud Bertrand, a senior scientist at the French National Research Institute for Sustainable Development, also worries about the Humboldt squid. These animals are an important income source for Peru’s artisanal fishers—they yield half a million tons of catch per year—and they tend to fare poorly during El Niños due to changes in prey availability. “If the Humboldt squid collapses, then you’ll have 10,000 boats that will try to find another resource,” Bertrand said. And because these artisanal fishers are less strictly regulated than commercial enterprises, all those boats looking for alternative species could have “huge, huge consequences for the ecosystem.”

Ultimately, the exact impacts will depend on how this El Niño forms and when its peak arrives. Exceptionally high temperatures in September could signal a more damaging El Niño, on par or similar to the disastrous one that struck in 1982. But even then, it’s hard to say exactly what will happen.

“Each El Niño is different,” Bertrand said, though climate change doesn’t make him optimistic. “With global warming, the worst is the most probable.”

This story was originally published by Grist and is reproduced here as part of the Climate Desk collaboration.