Farmed seaweed

Fresh, dried, baked, or fried, seaweed puts the green into Super Green. These nutritious, sustainable sea vegetables have been eaten for centuries—and you can try them too! This seafood is part of the Super Green List—seafood that’s good for you and the planet.

What are they?

If ever a seafood deserved the name super green, it’s seaweed! There’s no end to the ways seaweed is used. It can be eaten fresh, dried, frozen, cooked, used in baked goods, added to soups, rolled into sushi, and more. You also likely have seaweed in your home already without even realizing it. Extracts from seaweed are used as additives in foods and other consumer products—even beer! Giant kelp, for example, is a source of algin, an emulsifying and binding agent used in the production of many foods and cosmetics like ice cream, cereal, and toothpaste. The Monterey Bay Aquarium logo also represents the tip of a growing giant kelp!

The name seaweed is a little deceptive. They’re not plants at all. Seaweeds are a large, diverse group of marine macroalgae that can be subdivided into three distinct groups: brown, green, and red algae. Seaweeds don’t have roots, stems, or leaves like plants; instead, they have holdfasts, stipes, and fronds. While they might look similar, these features have different functions and structures. Holdfasts anchor seaweed to the seafloor, stipes are similar to stems, and fronds look a lot like leaves.

Seaweeds generally grow in coastal waters where they can anchor themselves to the seafloor but still get enough light for photosynthesis. Like plants, seaweeds use photosynthesis to create their own energy! Seaweed is an important component of ocean ecosystems. They provide oxygen, food, and habitat for fish and other marine species.

Good for you

Seaweed is one of the world’s most nutrient-dense foods. While each variety has its own unique nutritional profile, its general nutritional benefits include:

• Being a health powerhouse. Seaweed contains a variety of 23 essential nutrients, including vitamin A, iron, and magnesium.
• An excellent source of iodine, a mineral which supports thyroid function and a healthy metabolism.
• Bioactive compounds, such as astaxanthin, porphyran, and fucoidan, have been researched for their potential health benefits, including cancer-fighting, antioxidant, and anti-viral properties.
• Beneficial prebiotics, which promote a healthy gut microbiome and help boost immune health.
• Promoting heart health. Seaweed's natural profile of low to moderate sodium and high glutamic acid (an ideal salt substitute) levels helps keep dietary sodium intake in a healthy range.

Different types of seaweed provide different benefits. (Note: Seaweed omega-3 levels vary by species. See our FAQs at the bottom of the page for more information.)

• A kelp native to Japan, kombu has an astonishing 9333 percent Daily Value of iodine, 13 percent Daily Value of magnesium, and 14 percent Daily Value of potassium per serving (7 grams dried seaweed).
• A 7 gram serving of dried nori provides 98 percent Daily Value of iodine, 23 percent Daily Value of vitamin A, and 33 percent Daily Value of folate. This dried seaweed is often used to wrap sushi rolls.
• A brown kelp, wakame has 75 percent Daily Value of iodine and 24 percent Daily Value of magnesium per 7-gram serving (dried).

Good for the planet

In 2018, more than 32 million metric tons of seaweed were produced globally. About 99.5 percent of that is farmed in Asia, with over half coming from China. There are about 10 different major species of seaweed farmed for commercial use, but kombu (Japanese kelp) makes up about 35 percent of this global production.

Seaweed farmed using off-bottom culture is rated green for environmental sustainability and accounts for almost 90 percent of the seaweed farmed worldwide. Off-bottom aquaculture methods grow shellfish, seaweed, and more in ways that don’t harm the seafloor. The vast majority of seaweed is grown using floating rafts with netting or longlines attached to them, or lines that are staked to the ocean floor.

Overall, off-bottom culture methods have relatively few environmental impacts. For example, since these algae use sunlight and photosynthesis to nourish themselves, there’s no additional feed needed or nutrient waste discharged into the environment. Seaweeds also scoop up and store carbon dioxide and nutrients from the seawater around them.

Learn more about seaweed on Barnacle Foods’ Instagram

Ready, set, cook!

• Tuck your favorite sandwich fillings, like canned albacore tuna caught with trolls or pole-&-lines or chickpea salad, between two layers of nori sheets for a delicious, handheld lunch.
• Make sushi at home with seasoned rice, protein, and veggies.
• Shake kelp sprinkles over a bowl of popcorn for a touch of umami flavor.
• Blend sea moss or frozen kelp cubes into your favorite green smoothie for a boost of flavor and nutrition.

Where to find

Look for a variety of seaweed forms in your market, including:

• Fresh seaweed in prepared foods, like seaweed salad and sushi.
• Dried seaweed, including nori, kombu, and wakame, in sheets, pieces, flakes, and granules.
• Condiments, such as furikake (seaweed seasoning), seaweed granules, and flakes.
• Refrigerated pickled sea vegetables.
• Frozen seaweed smoothie cubes and kelp patties.
• Snacks, including crackers, chips, and snack sheets.

Top shopping tips

• Visit an East Asian supermarket to discover an even greater variety of easy-to-use seaweeds.
• Purchase dried seaweed, and rehydrate it by soaking it in warm water for 10-15 minutes. Drain, and use it in salads, soups, or side dishes.
• Grind nori sheets in a blender to create an inexpensive seaweed sprinkle to flavor your favorite dishes.

More FAQs