Last week, we introduced you to aquaculture as the farming of aquatic plants and animals as food. This week, we’ll take a closer look at aquaculture as an environmental tool and why it is such an important piece in meeting Maine’s environmental goals.

No land, feed, or water; the case for aquaculture and the environment

Although nearly 70 percent of planet Earth is covered by water, only a small percentage of the food we consume comes from the marine environment … and there is so much potential for seafood and marine products from the oceans. We’ve only just scratched the surface of this resource.

Kelp being harvested in Casco Bay by Bangs Island Mussels/Wild Ocean Aquaculture. Courtesy photo/Jaclyn Robidoux

Marine fisheries have historically produced more than 90 percent of the seafoods we consume, but we have fundamentally changed these ecosystems through overfishing, pollution, and human-induced climate change and today, marine environments are far less prolific than they once were. Aquaculture represents a way to supplement marine produce, while restoring marine ecosystems to their former capacities.

Terrestrial agriculture is a cornerstone of American culture and civilization. As our population has grown, moving farming out of our communities, industrial agriculture has become the de facto solution for food systems. They’re (industrial agriculture systems) also far more harsh on the planet. Terrestrial agriculture requires inputs like compost, fertilizer, and irrigation, while aquaculture does not.

Aquaculture production of shellfish and seaweeds using techniques like line or rope ‘seeding’ is amongst the most sustainable for cultivating food on the planet, because it is produced without these inputs. When developed and managed sustainably, aquaculture even has the potential to be regenerative, fostering a healthier environment for future generations of production.


Aquaculture production includes many species of fish you might be familiar with. Salmon, trout, yellowtail, and kingfish are the most common finfish varieties farmed here in Maine. Many varieties of shellfish we consume, like scallops, oysters, and mussels are also farmed here in the state’s coastal waters. Seaweeds like sugar kelp are being cultivated across Maine’s coastline and is making its way onto plates in so many unexpected ways – if you haven’t tried a kelp veggie burger, you need to.

Together, finfish, shellfish, and seaweeds create a balanced ecosystem providing for one another. Seaweeds reduce acidification by sequestering carbon at higher rates than terrestrial plants, which in turn helps nearly all marine organisms to build healthy cells, shells, and skeletons. Healthier shellfish enhance water quality through filter feeding and finfish produce waste that fuels seaweed growth and continued carbon sequestration.

At the local level, Casco Bay and the greater Gulf of Maine are highly susceptible to climate change impacts, which can be exacerbated by industrial scale aquaculture. Many coastal communities in Maine have pushed back against corporate interests in aquaculture to preserve their local fishing economies and marine environments. However, when managed appropriately, aquaculture positively correlates with improved water quality and ocean health. Increasing and improving on current aquaculture techniques benefit the state by producing seafood, withdrawing pressure on terrestrial agriculture and ecosystems, and sustaining coastal community economies in a time of great change.

Ultimately, the entire planet benefits from this cycle; nutrient dense produce, cleaner and healthier oceans which help to combat climate change impacts, and the continuation of our economies.

Aquaculture as other resources

Today, much of the biomass used to produce plastics is the byproduct of crude oil and petroleum refinement. A global search for clean, renewable biomass has led many to aquaculture and especially seaweed production. As seaweed production has ramped up globally, so has byproduct, opening an entire market for this renewable product.

Today, seaweed biomass can be fashioned into single use straws and cutlery, to-go containers, and even line or rope which can be used to produce more seaweed and shellfish. In the global push to cut carbon emissions and reverse climate change, moving away from fossil fuel products and towards renewable aquaculture systems is a no-brainer. Nutrient dense food and biomass produced with the future in mind.

Our Sustainable City is a recurring column in the Sentry intended to provide residents with news and information about sustainability initiatives in South Portland. Follow the Sustainability Office on Instagram @soposustainability.

Steve Genovese is an AmeriCorps/Greater Portland Council of Governments Resilience Corps fellow serving in the South Portland Sustainability Office through September 2023. He can be reached at [email protected]

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