Avoiding Food Scarcity on an Overpopulated Planet—Aquaculture’s Role in the Solution

By Emily Vidovich. Emily has a background in environmental journalism and sustainability and is a member of the George Washington University Class of 2019.

The future of food is fraught. By 2050, human population growth will increase the demand for food by 60 percent, while climate change, soil degradation, and urban expansion simultaneously reduce our ability to produce crops. According to the United Nations Foundation, crop yield could decline up to 30 percent over the next three decades.

Ensuring food security requires amending agricultural practices, supplanting wild-caught fish—many of which are already overfished—with sustainably farmed seafood alternatives, and collectively changing the way we consume food. In addition to safeguarding our species, these changes will also combat climate change, protect the environment, and expand economic opportunities.

Aquaculture off the coast of Greece. Photo by Alex Antoniadis on Unsplash

On land, farming practices such as tilling, which depletes soil and releases carbon dioxide (CO2) into the atmosphere, must be replaced with regenerative agriculture techniques that absorb CO2, restore soil health, and support the water cycle. Instituting better farming practices will also aid the fight against climate change, since nearly a quarter of global emissions come from agriculture and deforestation.

In the sea, expanding aquaculture could provide a less impactful food alternative to both wild fish and land-based livestock. According to the Nature Conservancy, raising fish takes less food, fresh water, and land than raising domestic farm animals. Moreover, farming shellfish and seaweed requires next to no resource inputs, and these species help the ecosystem by filtering the water, removing harmful excess nutrients, and absorbing CO2. These benefits, plus the fact that seaweed and shellfish farms provide habitats for wild fish, classify these modes of aquaculture as regenerative—reflecting their capacity to improve and restore ecosystems.

In society, people need to optimize their diets by obtaining a majority of their nutrition directly from plants. This would lead to a much more effective use of available farmland—100 grams of protein from beef requires approximately 20 times more land to produce than the equivalent amount of protein from legumes. 

Cultural shifts in food consumption will be the slowest of the three aspects of restructuring the global food system, since such changes largely fall outside the realm of legislation and will require long-term educational campaigns as well as individuals altering their dietary choices. As such, the shift towards regenerative agriculture and sustainable aquaculture—which can be incentivized and regulated—must be accelerated if humans hope to avoid a global food shortage.

AltaSea’s Blue + Green 2021 webinar series focused on the oceanic component of restructuring the food system by exploring the expansion of sustainable aquaculture. All types of aquaculture have seen continual growth over the past three decades—The United Nations Food and Agriculture Organization calculates that aquaculture production has risen 527% since 1990. In 2018, global aquaculture produced 54 million tonnes of finfish compared to 18 million tonnes of shellfish. Algaes such as seaweed were the second most farmed category after finfish, weighing in at 32 million tonnes.

As the farming of algae and shellfish continues to expand, experts anticipate increased benefits to ecosystems. Doctor Charles Yarish, who leads the Seaweed Marine Biotechnology Lab at the University of Connecticut, showcased aquaculture-derived ecosystem services during a yearlong experiment where he grew seaweed and shellfish in New York City’s East River.

The results were impressive. As Yarish explained in the first segment of AltaSea’s webinar series, the seaweed cultures not only thrived, they also filtered out excess nutrients that had been detrimentally affecting the river’s ecosystem.

Algaes, such as seaweed, and shellfish are nutrient-dense foods that can be sustainably harvested through aquaculture. Photo by Silas Baisch on Unsplash

Discussing the future of aquaculture necessitates acknowledging that much change is needed in order to make this type of sustainable aquaculture mainstream. Over the past few decades, aquaculture has been coupled with negative environmental impacts. Farming finfish such as salmon contributes to overfishing, since a large percentage of wild-caught fish are used to feed farmed fish. In parts of Asia, the shrimp farm industry is a major driver of the deforestation of ecologically important mangrove forests.

This environmental degradation underscores the importance of creating regulatory frameworks at local, national, and international levels that promote sustainable aquaculture practices, phase out detrimental ones, and support farmers so they can utilize best practices.

Effective management strategies must also be used to increase the sustainability of aquaculture—reliance on wild fish can be reduced by obtaining a majority of the food for farmed fish from algae, and marine spatial planning can identify areas where installing shellfish and seaweed aquaculture would be the most beneficial. 

If aquaculture expansion operates under an ethos of environmental integrity, it will be an irreplaceable component of a restructured, sustainable global food system. Avoiding severe food shortages will be one of the major challenges of the coming decades, but as with many of the challenges facing our blue planet harnessing ocean solutions is integral to solving it.