Sustainable Aquaculture: The Seaweed Industry in New England


On Thursday, the Tufts Environmental Studies department was visited by Lindsay Green, a PhD and researcher focused on seaweed physiology, aquaculture and ecology. Aquaculture refers to the farming of aquatic organisms including fish, shellfish, and seaweed. World aquaculture has been expanding by about 10% per year for decades, with most of that consisting of fish. Approximately 1/4 of current aquaculture production consists of plants and seaweed. Despite this growth, the U.S. accounts for only 1% of aquaculture production, which contributes to its over $10billion trade deficit for seafood. China, on the other hand, produced 23.8 million tons of seaweed alone in 2012. China and Indonesia together make up 81.4% of global seaweed aquaculture production.

In New England, the majority of the aquaculture industry is in shellfish.  However, there are a few companies in Maine growing both kelp and dulse on a commercial scale. Much of this is intended for direct consumption, but seaweed is also valuable for its use in biomedical applications, textiles, animal feeds, and agricultural crop enhancement.

Porphyra umbilicalis, the nori seaweed from your sushi

Porphyra umbilicalis, the nori seaweed from your sushi*













Integrated Multi-Trophic Aquaculture

IMTA is a system in which the potentially environmentally harmful effects of fish aquaculture are used to enhance production of shellfish and seaweed aquaculture. Waste materials from one species serve as food or fertilizer for the next, creating a loop of healthy and sustainable aquaculture.

IMTA: Integrated Multi-Trophic Aquaculture

IMTA: Integrated Multi-Trophic Aquaculture****

Green’s research has focused on optimizing seaweed production for conditions found off the New England coast. She found that local seaweed and kelp species tend to grow more rapidly under long exposure to sunlight, by phycobilins (good pigments) and protein tend to develop more with less sunlight. These are all important components of a quality seaweed product, so Green suggested a short, heavily lit production cycle followed by a “finishing off” period of relative darkness. This would allow optimal growth with an opportunity to produce pigments and proteins.

Keep your eyes open for locally grown seaweed! It can be grown sustainably in our delicate ocean ecosystems and there is already a huge market for it in other parts of the world. Could kelp be the next kale?