As demand for seafood and pressure on the ocean grows with the increasing human population, alternative sources of food are also expanding. We’ve discussed how farming seafood, also known as aquaculture, is one such growing sector that will likely soon produce more than wild caught fisheries. But not all of the ocean’s bounty is categorized as fish or shellfish—seaweeds are also gaining popularity, in part due to their health benefits and part due to the recognition of these plants as a sustainable item.
Kelp is a type of seaweed very popular in Asia now making its way into mainstream U.S. food culture. It’s used in shellfish dishes, as an ingredient in beauty products, and to wrap up sushi rolls. But instead of harvesting or collecting wild kelp, many are turning to farming it.
The promise of farming kelp and similar seaweeds lies in their low maintenance and ecosystem services. Seaweeds need two things to grow: seawater and sunlight. This lack of inputs makes the product sustainable—there is no feed or tanks or filtration system required, if done in the open ocean. And the ecosystem services provided by seaweeds include the massively important act of carbon sequestration, which in the ocean works to maintain the sea’s acidity levels.
GreenWave, an organization dedicated to growing the blue-green economy, developed an aquaculture system called 3D Ocean Farms along with a training program for farmers. Their system makes use of the entire vertical water column, allowing the farmer to diversify his crops with shellfish and seaweeds and yield tons from a single acre. It’s also input-free, since all that’s required to grow seaweed like kelp is ocean water and sunlight, and shellfish are filter feeders that get their nutrition simply by cleaning the seawater.
In Maine, the Bigelow Laboratory for Ocean Sciences is working to help grow the state’s aquaculture market, which includes seaweeds. One scientist is studying the relationship between seaweeds and commercial shellfish as ocean acidification takes place in the Gulf of Maine. Increasing acidity negatively affects mussels, oysters, and clams, but the increasing carbon dioxide is leading to greater productivity of seaweeds. And seaweeds are able to sequester carbon. Her research could indicate that farming kelp alongside oysters is a win-win.
Not only is seaweed a food option for an ever-hungry human population, but it is also a tool for combating climate change. Keep an open mind for this food of the future, and try the seaweed salad.