Fish Farming Could Help Save the Planet and Feed the World

The Fish We Forgot About

The most important food revolution of the next fifty years is not happening on land. It is happening underwater, in pens and ponds and recirculating tanks, and it is run by people who have figured out something the rest of the world has not: that farming fish might be the single best way to feed a growing population without destroying the planet.

This is not obvious. Aquaculture, the farming of fish, shrimp, and shellfish, has a reputation problem. People think of overcrowded salmon pens, antibiotics, and fish that eat more wild fish than they produce. Those problems are real, but they are not the whole story. A 2023 review paper by Max Troell and colleagues, published in the Journal of the World Aquaculture Society, makes the case that aquaculture is not just a marginal food source. It is a sector that could help achieve nearly every one of the United Nations Sustainable Development Goals, from ending hunger to protecting life below water (Troell et al., 2023).

The authors are not naive. They know aquaculture has problems. But they argue that the way we talk about food systems is broken. We treat agriculture as the default and aquaculture as an afterthought. This is a mistake. Fish farming is not a niche alternative to chicken and beef. It is a fundamentally different kind of food production, with different environmental pressures, different nutritional outputs, and different possibilities for sustainability.

Here is what surprised me: the paper argues that aquaculture's biggest strength is its diversity. There is no single "aquaculture industry." There are hundreds of them, from small ponds in Bangladesh to high tech recirculating systems in Norway. Some systems produce more protein per unit of land than any terrestrial farm. Some use no freshwater at all. Some actually clean the water they are in.

The question is not whether aquaculture can help save the planet. It is whether we can stop treating it like a second class citizen and start building policies that let it do what it does best.

Why the UN Almost Missed the Boat

The Sustainable Development Goals, adopted by all United Nations member states in 2015, are supposed to be a blueprint for a better world. They cover everything from poverty to climate action. But when the goals were written, aquaculture was barely mentioned.

Troell and colleagues point out this absence directly. They note that "the important role for food security, nutrition, livelihoods, economies, and cultures is not clearly visible in the Agenda 21 declaration" (Troell et al., 2023). The authors suggest this might be because aquaculture policies are underdeveloped compared to agriculture, and because most fish farming historically happened in a few regions like Southeast Asia and China.

This matters because what gets measured gets managed. If the SDGs do not track aquaculture's contributions, governments will not invest in it. The paper is essentially a correction: a systematic attempt to show how fish farming connects to the goals, and a warning that ignoring it means missing one of the most promising tools for sustainable development.

The authors conducted a rapid literature survey, mapping aquaculture's links to specific SDG indicators. What they found is that fish farming touches far more goals than most people assume. It is not just about hunger (SDG 2) and life below water (SDG 14). It connects to gender equality (SDG 5) because women do much of the processing and marketing in many regions. It connects to decent work (SDG 8) because millions of small scale farmers depend on it. It connects to responsible consumption (SDG 12) because fish are among the most efficient converters of feed into protein.

The paper is not a single experiment. It is a synthesis, pulling together decades of research to make a structural argument. The authors examined case studies from around the world, looking at different farming systems and measuring their impacts across multiple SDGs. They built a conceptual framework to show that the same type of aquaculture can produce very different outcomes depending on where and how it is done.

The Shrimp Pond That Saves the Mangrove

Here is where the story gets interesting. The paper includes case studies that illustrate both the promise and the complexity of aquaculture.

One case study involves shrimp farming in Vietnam. Mangrove forests are among the most carbon rich ecosystems on Earth, and they are also critical nursery habitats for wild fish. Traditional shrimp farming has been a disaster for mangroves. Farmers clear cut them to build ponds, then abandon the ponds after a few years when disease hits.

But Troell and colleagues describe a different model: integrated mangrove shrimp farming. Farmers keep the mangrove trees standing and raise shrimp in the channels between them. The trees filter the water. The shrimp eat naturally. The system produces less shrimp per hectare than an intensive pond, but it keeps the mangrove intact. The authors found that this approach supports SDG 13 (climate action) by storing carbon, SDG 14 (life below water) by preserving habitat, and SDG 1 (no poverty) by providing a steady income (Troell et al., 2023).

The trade off is real. You get less shrimp. But you also get a functioning ecosystem, a carbon sink, and a livelihood that lasts longer than three years. The paper argues that these trade offs need to be made visible, not hidden. Right now, most policy conversations treat aquaculture as a single category. A shrimp farm is a shrimp farm. But the difference between an intensive pond and an integrated mangrove system is the difference between a factory farm and a regenerative farm.

Another case study looks at seaweed farming in Indonesia. Seaweed requires no feed, no freshwater, and no land. It absorbs nutrients and carbon dioxide. It provides habitat for fish. And it is one of the fastest growing sectors in aquaculture. The authors note that seaweed farming supports SDG 2 (zero hunger) by providing income and nutrition, SDG 8 (decent work) by employing coastal communities, and SDG 14 by reducing ocean acidification locally (Troell et al., 2023).

These are not hypotheticals. These are operating farms, producing food right now, with measurable environmental benefits.

The Feed Problem Is Not What You Think

The most common criticism of aquaculture is that farmed fish eat more wild fish than they produce. This was true for salmon and shrimp twenty years ago. It is not true anymore.

Troell and colleagues address this directly. They point out that the ratio of wild fish used in feed to farmed fish produced has been dropping for decades. For some species, like tilapia and carp, the ratio is now below one. These fish are net producers of protein. They eat mostly plant based feed, with small amounts of fishmeal and fish oil added for essential nutrients.

The paper also highlights that not all fish are the same. Bivalves like mussels, oysters, and clams require no feed at all. They filter plankton from the water. They actually improve water quality. Seaweed requires nothing but sunlight and nutrients. The authors argue that when people talk about aquaculture, they usually mean salmon and shrimp, which are only a fraction of global production. The sector is far more diverse than its reputation suggests.

The real feed problem, the paper suggests, is not about fish. It is about the ingredients in fish feed. Many farmed fish eat feed made from soy and corn, which require land, water, and fertilizer. This creates a connection between aquaculture and deforestation in places like the Amazon. The authors call for more research into alternative feed ingredients: insect meal, algae, single cell proteins, and byproducts from other food processing.

This is where the paper gets specific. Troell and colleagues note that "aquaculture is a unique sector that encompasses all aquatic ecosystems and is also tightly interconnected with terrestrial ecosystems through feed resources and other dependencies" (Troell et al., 2023). In other words, you cannot solve aquaculture's problems by looking only at the water. You have to look at the whole supply chain.

The Freshwater Paradox

One of the most important findings in the paper is about water use. Aquaculture uses water, obviously. But the authors found that the type of water matters enormously.

Freshwater aquaculture, which includes carp, tilapia, and catfish, uses water that could otherwise go to crops or drinking. Marine aquaculture, which includes salmon, sea bass, and seaweed, uses saltwater that has no other use. Brackish water aquaculture, which includes shrimp and milkfish, falls in between.

The authors argue that future growth should prioritize marine and brackish systems, to avoid competing with terrestrial food production for freshwater. They also point out that some freshwater systems, like integrated rice fish farming, can actually increase water efficiency. In these systems, fish are raised in rice paddies. The fish eat pests and weeds. Their waste fertilizes the rice. The water does double duty.

This is not a niche practice. Rice fish farming is common in parts of Asia and is being tested in Africa. The paper notes that it supports SDG 2 (food security), SDG 6 (clean water), and SDG 12 (responsible production) simultaneously (Troell et al., 2023).

What the Paper Does Not Prove

The authors are careful not to overclaim. They acknowledge that aquaculture can cause serious harm. Poorly managed farms pollute waterways, spread disease, and destroy habitats. The paper is not an argument for all aquaculture. It is an argument for better aquaculture.

One important limitation is that the paper relies on existing data, which is uneven. Some countries track aquaculture statistics carefully. Others do not. The authors call for better monitoring and for national governments to include aquaculture in their SDG reporting.

Another open question is about scale. The case studies in the paper are promising, but they are small. Can integrated mangrove shrimp farming feed the world? Probably not on its own. But the paper argues that it does not need to. The goal is not to replace all terrestrial agriculture with aquaculture. The goal is to integrate aquaculture into a diverse food system, where each sector does what it does best.

The paper also does not resolve the tension between intensive and extensive systems. Intensive systems, like recirculating tanks, produce a lot of fish in a small space with tight control over waste. But they require energy and capital. Extensive systems, like ponds and pens, use less energy but more land and water. The authors do not pick a winner. They argue that different systems are appropriate for different contexts.

The Policy Gap

If aquaculture is so promising, why is it not growing faster? The paper points to policy.

Agriculture has centuries of policy support: subsidies, research funding, extension services, and trade agreements. Aquaculture has almost none of these in most countries. The authors argue that this is a historical accident, not a rational choice. When the SDGs were written, aquaculture was still a small sector in most of the world. Now it is the fastest growing food production system on the planet.

The paper calls for "a cohesive and comprehensive aquaculture strategy, framed to meet the SDGs" (Troell et al., 2023). This means governments should stop treating aquaculture as a subset of fisheries and start treating it as its own sector, with its own goals, metrics, and support systems.

It also means recognizing that aquaculture is not just about food. It is about livelihoods, gender equity, climate resilience, and ecosystem health. The paper shows that a well designed aquaculture farm can contribute to multiple SDGs at once. A poorly designed one can undermine them.

What This Actually Means

• ▸Stop thinking of fish farming as one thing. A mussel farm and a shrimp farm have almost nothing in common except that they both involve water. Policies and investments should be species specific and system specific. A blanket ban on aquaculture would kill the good along with the bad.

• ▸Prioritize marine and brackish systems for growth. Freshwater is already scarce. The future of aquaculture should be in the ocean, in estuaries, and in systems that do not compete with crops for water.

• ▸Invest in feed alternatives now. The biggest environmental risk from aquaculture is not the fish. It is the soy and corn in their feed. Insect meal, algae, and fermentation based proteins need to move from pilot scale to commercial scale within a decade.

• ▸Measure what matters. Most countries do not track aquaculture's contributions to nutrition, employment, or environmental impact. Without data, policymakers cannot make good decisions. National statistics agencies should add aquaculture specific indicators to their SDG reporting.

• ▸Support integrated systems, not monocultures. The most promising models combine fish, plants, and sometimes livestock in ways that mimic natural ecosystems. These systems produce less per unit of area but more per unit of environmental cost. They are harder to industrialize but more resilient in the long run.