By: Anoushka Concepcion, Connecticut Sea Grant and UConn Extension


Photo credit: Nancy Balcom

Connecticut has an extensive agricultural industry that extends far beyond land. Hidden under its coast, lies more than 70,000 acres where one of the best protein sources is produced – shellfish (clams, oysters, mussels, and scallops). The shellfish aquaculture industry is over 150 years old and expanding in numbers of producers, and additional products. But shellfish are not the only crops that grow underwater. Seaweed, or sea vegetables, is a highly valued commodity at $8-10 billion in the global market. Seaweeds are consumed for their nutritional benefits and are a staple in Asian diets. Their components are in a wide range of products including fertilizers, animal feeds, nutritional supplements, cosmetics, and biofuels. Seaweeds also provide ecosystem services; they can be used to clean up waterways by extracting excess nutrients from urban runoff.

Although the majority of production occurs in Asia, interest in seaweed production is increasing in the United States. For many years, seaweed has been harvested from the wild. However, the cultivation (or aquaculture) of domestic seaweed is increasing. Current producers of seaweed include shellfish producers and displaced lobstermen looking to diversify products and income. There is also an interest from municipalities who are looking at seaweed for ecosystem services. Currently in Connecticut, there are two types of seaweed cultivated and approved for food: the sugar kelp, Saccharina latissima and Gracilaria tikvahiae. The kelp grows in the winter season while the Gracilaria grows in the summer. There are four commercial farms growing sugar kelp. These farms are small-scale and mostly grow shellfish.

Connecticut Sea Grant has been involved in seaweed aquaculture for almost 30 years, funding extensive foundational and applied research of Dr. Charles Yarish in the Department of Ecology and Evolutionary Biology. More recently, Sea Grant and UConn Extension have been helping transfer aspects of the research to industry and market, along with Yarish and other collaborators. Sea Grant has been addressing several bottlenecks hindering further expansion of this new industry. The major bottleneck is lack of federal guidelines on the public health aspect of domestic seaweed production and processing. Since the majority of seaweed domestically produced is from wild-harvest, it has been unregulated. There are guidelines ensuring seafood, meat, dairy, and other agricultural commodities are safe for human consumption. However, we don’t have similar guidelines for cultivated seaweed. This presents a problem for state regulatory agencies that are trying to ensure the seaweed grown in Connecticut is safe. Sea Grant and UConn Extension partnered with the Connecticut Department of Agriculture’s Bureau of Aquaculture to develop guidelines that allow locally produced seaweed to be grown and sold in the state. This guide contains handling, storage, and processing guidelines for both species of seaweed grown in Connecticut.

Seaweed can grow quickly and in large volumes, requiring harvesting be done all at once. Since seaweed has a short shelf life – it starts to degrade within hours, it must be used right away or processed into a form that will last. Local chefs desire raw kelp since it is fresh and unprocessed, but it has a very short shelf life. Kelp has also been processed into noodles and sold to a limited number of restaurants and retailers in the region. In 2013, Sea Grant assisted the Bureau of Aquaculture in approving the first commercial seaweed grower to sell fresh kelp and kelp noodles as food. This involved providing development funds testing the safety of both forms of kelp and seafood safety knowledge to determine appropriate handling, storage, and processing guidelines. The seaweed grower has now expanded to a large-scale commercial kelp processing facility in New Haven, Sea Greens Farms; that can accommodate seaweed produced by other growers in the region. Although guidelines have been developed for raw and kelp noodles, they have not been developed for dehydrated or dried seaweed. Sea Grant is working with a local food manufacturer to conduct drying experiments to determine if there are any potential hazards associated with dehydrating seaweed. Although experiments are ongoing, preliminary results indicate that as long as the seaweed is stored and handled properly, it should be safe to eat.

Additional experiments are being conducted to determine if the summer seaweed, Gracilaria, is suitable for human consumption when cultivated in Connecticut’s coastal waterways. Gracilaria can remove heavy metals and other chemicals from the water, making it a great candidate for nutrient bioextraction to clean up waterways. However, there is no data showing that it is safe for human consumption.   Currently, only Gracilaria cultivated in indoor tanks can be sold as food, since growing conditions can be controlled ensuring product safety. Experiments analyzing Gracilaria grown in Connecticut waters are underway to determine its feasibility as a food product. Additional barriers under investigation include expanding markets for local product and the successful transition of kelp seed-string production from research labs to commercial-scale. Although the production of seed-string has begun to shift into the hands of commercial seaweed operations, it is not fully independent and at the same level as the shellfish aquaculture industry. An extensive seafood marketing survey this summer will assess awareness and consumption of Connecticut seafood and seaweed among residents.

Although the potential for seaweed aquaculture in Connecticut is huge, there are constraints to rapid expansion. The domestic seaweed aquaculture industry is still in its infancy and it is yet to be determined if it will become more than a niche commodity. Overcoming these constraints will take time, as with any new product. However, this new crop may contribute to sustaining and creating new jobs as well as providing additional ecosystem services for Connecticut’s coastline.