Fishing for Global Health

by Jackie Swift

The world’s fisheries sustain millions of people. The food they provide is crucial for human nutrition and livelihoods. Yet the ecosystems that produce aquatic foods face unprecedented challenges from pollution, overfishing, and climate change. Determining how to manage these ecosystems requires that we think about environmental issues in tandem with the social, nutritional, and livelihood needs of the people who depend on them, says Kathryn J. Fiorella, Public and Ecosystem Health.

“The environment isn’t separate from people and their societies; they’re all really intricately intertwined,” says Fiorella, who carries out research from a One Health paradigm, which focuses on the relationships between humans, animals, and the environment, and the impact of those relationships on the health of populations. “The changes that are happening to our planet are going to impact our health in many ways, and figuring out how that’s going to happen, and mitigating it, is becoming more and more important.”

Fiorella looks mainly at freshwater global fishery systems. Much of her work has been centered specifically on fisheries in the Tonle Sap Lake region of Cambodia and in the portion of Lake Victoria that lies within Kenya. Lately, she has begun some projects in Upstate New York, as well.

To Fish or Not to Fish—There’s More to the Question

In Cambodia, Fiorella and her lab studied the effects of climate change on how people fish. Using data sets from WorldFish, an international nonprofit research organization, the researchers considered the behavior of small-scale fishers in Cambodia from 2012 to 2015.

“A lot of times, when climate change gets modeled, we look at what the impact of climate will be on fish populations, and then we think about the implications of that,” Fiorella says. “But the reality is that fishers also make decisions about how much they will harvest and what kind of effort they’ll put into fishing versus some other aspect of their livelihoods. So we want to think about both how the climate is affecting the ecological dimensions of the fish population and how it is affecting people’s behavior and maybe changing whether they fish or the ways that they fish.”

Fiorella and her colleagues found that people were fishing less when temperatures rise, but they were catching a similar total amount of fish as before. In essence, the higher temperature had no effect on the overall catch itself, but it did have an effect on whether people participated in fishing.

“We think that warmer temperatures are changing not only what’s going on with fisheries but also what’s happening with agriculture,” Fiorella says. “For instance, when it’s warmer, there may be an increased need for people to deal with weed growth. In other words, higher temperatures affect multiple dimensions of livelihoods, so people rebalance how much time they spend on things.”

A large-scale event like climate change touches on many facets of ecosystems and human behavior that must all be taken into account, Fiorella says. “If we only look at the ecological piece, and we don’t meaningfully factor in how people are going to respond to those ecological changes, then we’re going to miss big pieces of what’s going on,” she explains. “And those might have real implications for the health and wellbeing of the people who live and work in these systems. In the worst-case scenario, we might even misdirect our responses to things like climate change because we’ve misrepresented what the implications could be.”

Different Fish, Different Nutrition

To better understand the impact of fisheries on human health and nutrition, the Fiorella lab contributed to Blue Food Assessment, a collaboration among more than a hundred researchers from diverse academic and nonprofit centers exploring the role of aquatic foods in human nutrition. The researchers compiled a set of nutrient composition information about many of the hundreds of fish species eaten throughout the world.

“The nutrient composition of many of these fish is not very well known,” Fiorella explains. “Fish tend to be treated as if they are all the same. Often, we survey people and ask how much fish they ate, but not which fish species. It turns out that a lot of fish—especially the small, pelagic ones—are really high in important micronutrients like vitamin A, iron, zinc, and selenium, which a lot of people around the world are often deficient in.”

“Often, we survey people and ask how much fish they ate, but not which fish species.”

Understanding the differences in nutritional components among fish species has led Fiorella to some interesting questions about the consequences of transitioning to aquaculture, in which a handful of preferred fish species are intensely farmed for food, as well as about the importance of wild fisheries on human health. “The reality is that we can’t depend on wild fisheries to increase fish supply; they aren’t going to be able to meet our needs,” she says. “The increase is going to come from farmed systems, and that’s going to be a big change. We’re at the juncture of an important transition, and now is the time to get the policy right for how farmed fish will be produced.”

Algal Blooms

In another project focused on Lake Victoria, Fiorella has turned her attention to harmful algal blooms, rapid overgrowths of microscopic algae in a body of water. Around the world, harmful algal blooms are becoming more common and more intense as farm runoff and inadequately treated sewage provide nutrients that feed algal growth. At the same time, global warming further stimulates algal growth and lengthens the growing season. Fish seem to be able to coexist with the algae, but the toxin the algae produce—known as microcystins—can cause a host of symptoms in humans, from skin rashes to liver damage.

Currently Fiorella is investigating the ramifications of algal blooms on the health and livelihoods of people fishing in the lake. “Fishers in the region say their skin is itchy and irritated from contact with the algae and that they have respiratory and gastrointestinal problems because of the blooms,” she says. “They also have to go further away to fish in areas where the water is cleaner. On top of that, pulling their nets through the algae is much more difficult, so the blooms have physical implications, as well.”

Local Needs, Global Food Systems

Fiorella emphasizes local perspectives in her research by including the needs of the people who are working and living with these fishery systems. “I try to make sure the research I do is of value to them from the start,” she says. “For instance, I want the questions we’re asking in the research to be relevant so they can take up our findings and make use of it in their policies.

“My other goal is to stop us from thinking about these things in silos,” she continues. “Fishery organizations should be thinking about health outcomes, for instance. We manage nutrition separately from how we manage food production. We wind up not necessarily optimizing for the outcomes that we care about. When we can bring everything together and think about people’s health and wellbeing in the context of these production systems, that will affect how we think about, understand, and plan for these things so that we end up with food systems that work better for us.”

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