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New research shows shrimp can lose their flavor when ocean chemistry shifts.

Environment Health Ideas Issues Systems

The international panel of experts studying the global impact of climate change released a sobering report on Wednesday: The oceans, which have long acted as buffers against the worst consequences of heat waves and carbon emissions, are in trouble. The study, which was put together by more than 100 scientists from more than 30 countries, is a comprehensive assessment of current climate science concerning the planet’s water. It was released by the Intergovernmental Panel on Climate Change, the U.N. body that has also released massive reports on the potential impacts of global temperatures rising by 1.5 degrees Celsius and the impact of climate change on land resources

We’ve heard a lot of it before. Glaciers are melting. Sea levels are rising. And it’s all happening faster than ever. Much of this will impact fish harvested for seafood and the fishermen and eaters who rely on them. We’ve long known that conditions caused by climate change will make it harder for oysters and mussels to grow their shells—already, oystermen in the Pacific Northwest are shipping their seeds to Hawaii to get a head start on life before growing up in harsher waters. We were also already aware that changing waters cause population shifts: Commercial fishing boats based in North Carolina have been shifting about 13 miles north every year since 1997.

But emerging research has revealed that changing ocean chemistry will impact our favorite seafood species on a molecular level. Acidifying waters will alter the taste and texture of shrimp cocktail and po’ boys, and scientists are hoping that educating people about these changes will spur them to action. The question is whether or not we’ll even notice fish gradually losing their flavor over the course of several decades. 

“You can actually taste acidification.”
Sam Dupont, a researcher at the University of Gothenburg in Sweden, has completed multiple studies on the impact of ocean acidification on Northern shrimp. He chose the species because of the ubiquitous status of this particular food item in Sweden. “When you ask around, people eat it from one to four times a month,” he says. Dupont wanted to help eaters connect the dots between climate change and the plate. The end goal wasn’t to publish a paper—it was to drive behavioral change. “It was not an industry-based approach, it was more like a communication strategy,” he says. 

Dupont’s team exposed the shrimp to water chemistries that mimicked the levels of carbon dioxide forecast a few decades from now. Then, they asked chefs to prepare them side by side with shrimp grown in 2019 conditions. A panel of tasters sampled each plate. Surprisingly, most could taste a difference. And most preferred today’s shrimp over the shrimp grown under acidified conditions—a taste of things to come. “That was kind of the first step: You know, like you can actually taste acidification,” Dupont says. 

Generally speaking, the tasters said the future-shrimp was simply less flavorful than today’s catch. Dupont repeated the experiment three times and got the same feedback. Then he tested the impact of the side-by-side tastings on eaters’ hearts and minds. He gave a group of students a fifteen-minute talk about ocean acidification and then quizzed them on the likelihood that they’d cut back on carbon-intensive activities like driving. He gave another group of students the same talk followed by a shrimp sampling. Unsurprisingly, the tasting group showed a stronger commitment to changing their behaviors. 

In the U.S., we may see dramatic shifts in seafood quality and availability long before chefs and fishmongers start to ring the alarm bells over taste and texture.
Interestingly, the findings may not translate across species and cultural boundaries. Dupont repeated the experiment with local mussels and a group of tasters that included both international visitors and locals. The locals were loyal to the 2019 shellfish, but the visitors generally preferred the mussels grown in acidified water. Dupont is in the process of launching a version of the study to examine key seafood species in 15 different countries. The goal is to identify potential changes in taste and texture, but also to look at the broader impacts of ocean acidification on food fish: survival rates, growth, migration. 

Of course, ocean acidification is a global issue. Even if students in Sweden cut back on beef consumption, there’s no guarantee their beloved shrimp will continue to thrive. Still, Dupont thinks drawing the emotional connection between eating and conservation is worthwhile. “All these initiatives to promote individual changes are really important, because by doing that, you realize, okay, things will change. But if I want to make it better, I will have to accept certain things that are not really popular, or will affect our quality of life a little bit. I’m pretty sure we can find a way to optimize our quality of life.” 

In the U.S., we may see dramatic shifts in seafood quality and availability long before chefs and fishmongers start to ring the alarm bells over taste and texture. Harold Dieterle, a lifelong fisherman and the winner of the first season of Top Chef, says he hasn’t pinpointed any specific, consistent changes in fish flavor over the course of his career. There are just too many variables that impact the catch, such as seasonality, size, and water temperature. He says the most noticeable trend in the Northeast has been an overall decline in fish populations. “I’ve been fishing my whole life, and I’ve certainly seen, you know—the depletion of wildlife in the water has been massive since I first started fishing as a kid,” he says. 

As the ocean chemistry changes, die-offs are likely to become more common.
In the South, warming waters will also mean increasing prevalence of Vibrio pathogens and harmful algal blooms, according to the IPCC report. Stephanie Villani, a co-owner of Blue Moon Fish and the author of The Fisherman’s Wife: Sustainable Recipes and Salty Stories, says she’s stopped eating raw shellfish when she travels to Florida each winter for fear of food poisoning from Vibrio. “It’s really, really hair-raising,” she says. “You can get paralyzed.” Literally.

Villani hasn’t noticed any long-term taste alterations in the Long Island catch, either. She says she thinks it’ll take real scarcity to awaken consumers to conservation issues. About 20 years ago, a brown tide killed massive numbers of bay scallops. (Brown tides are caused by harmful algal blooms.) “There were so many around, it was crazy. They’re so sweet and good. But then they died and there were hardly any left for 10, 15, 20 years. And that’s when people got upset,” she says.

But the bay scallops have since made a comeback, largely due to replanting efforts. These kinds of efforts—which can rehabilitate beloved species after a population crash and potentially prevent further disaster—are what Dupont hopes to prepare for with his 15-country study. As the ocean chemistry changes, die-offs are likely to become more common. Dupont is hoping that his work connecting the dots between taste and conservation will encourage eaters to protect iconic species before it’s too late.

H. Claire Brown

Claire Brown is a staff writer for The New Food Economy focusing on food policy and the environment. Her reporting has won awards from the Newswomen’s Club of New York and the New York Press Club. She is based in Brooklyn. She can be reached via email at [email protected] or on Twitter at @hclaire_brown.

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