Bladderwrack: Gift from the Sea

This past week my family and I got away for one last beach get-away to Maine. I love the languid and liminal days of late summer on the coast when the Rose Hips start to ripen and the ocean-side Goldenrod is in bloom- it’s my favorite time to visit. So subsequently it’s when I tend to harvest my seaweed! That being said, many folks prefer to harvest Bladderwrack (Fucus vesiculosus) in the spring and early summer, however, it’s definitely possible to harvest this seaweed well into August.

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Bladderwrack: Identification, Habitat & Range

Look for this seaweed growing on rocks in the inter-tidal zone, the area of the shore effected by the tides. Here on the eastern coast of the US it’s found south to about North Carolina and north all the way up the Canadian coast. It grows on the coast of the British Isles, the Atlantic coast of Europe, Iceland, southern Greenland, and the northern coasts of Norway, Finland, and Russia as well. On the west coast of the US a related species, Fucus gardneri, is used. Our local Bladderwrack (F. vesiculosus) is easily identified by the air bladders ranging in size from a pea to a marble found in pairs along the mid-rib of the thallus (the entire vegetative body of a seaweed). There can be some variation, however. Occasionally the bladders are not found in pairs, and their amount will vary based on the turgidity of the water- the more active the wave action the fewer bladders will be found. It grows along with other Fucus spp seaweeds but is the only one with the air bladders present. The fronds tend to be dichotomously branched and can grow to be about 35 in long and 1.0 in wide and have mucilage-rich vesicles at their tips. It’s a perennial macroalgae that tends to live 4-5 years.

Bladderwrack  (F. vesiculosis) . Note the air bladders along the mid-rib and the swollen vesicles at the tips on the fronds

Bladderwrack (F. vesiculosis). Note the air bladders along the mid-rib and the swollen vesicles at the tips on the fronds

Sustainably Harvesting Bladderwrack

Bladderwrack is best harvested in the spring and early summer when the vesicles are nice and plump. However, if need or circumstances be, it can be harvested well into late summer. As it reaches maturity the vesicles will elongate, so the more long and pointed the vesicles the older the seaweed. The bottom-line though is that as long as the thallus is vibrant-looking (see the pictures above and below for an idea of what I mean by vibrant), it’s fine to harvest if that’s when you’re by the sea!

Bladderwrack growing on a cliff edge with Rockweed  (Ascophyllum nodosum)

Bladderwrack growing on a cliff edge with Rockweed (Ascophyllum nodosum)

Waiting for low tide will give you the best access to Bladderwrack, which grows on rocks and along coves, generally mixed with other seaweeds such as Spiralwrack (Fucus spiralis ) and Rockweed (Ascophyllum nodosum) . When harvesting this-or any seaweed- it’s important that you never pull the holdfast, which is where it attaches to the rock, since this will completely kill the organism. Rather, you want to give it a gentle haircut with scissors or garden clippers, taking about 1/2 of the thallus, which will allow it to grow back. I like to harvest into a basket or even a brown paper bag. Give it all a good rinse in the seawater to remove any excess sand and also to wash off any organisms, like snails, from the seaweed. DO NOT wash in fresh water as this will cause it to begin to breakdown! Then, if you’re going to stay at the beach for a bit, you can lay it in a thin layer on a towel or blanket in the sun to begin to dry it.

Never take all the Bladderwrack from a rock, wall or area, remembering that good harvesting practices mean it was never even obvious that you harvested at all! Think of yourself like a browsing deer wandering through a meadow, taking a little bit from here, a little bit from there, and so on. Take care if you are walking on seaweed-covered slippery walks while harvesting. And never take more that you need! In Maine harvest for personal use is permitted and commercial harvest requires a permit. Always be sure you are harvesting in an area free of industrial waste and pollution and harvesting far from urban centers is strongly recommended.

Bladderwrack and other intertidal zone seaweeds growing on rocks at low tide

Bladderwrack and other intertidal zone seaweeds growing on rocks at low tide

Drying & Storage

It’s traditional to hang seaweed in the sun on a line to dry. In warm, dry climates it can dry in this way in a day but here in the northeast not so much! While it’s true that seaweed left out on a line will absorb some moisture from the morning dew, it’s not enough to cause any worry and a few days dried in the sun in this way tends to be enough. If it’s cloudy and overcast, then it will take longer and if rain is projected then it should be brought inside and re-hung after the rain. On my most recent trip to Maine we were camping so I hung it on a line to dry. It wasn’t completely dried by the time I got home so I opted to spread it in a thin layer in some large baskets and put it in my hoophouse, which is warm and dry and sheltered from the rain. At least once a day I tossed the Bladderwrack around a bit in the basket, since the parts more exposed to air dry quicker, and this allowed it to evenly dry. It finished drying in a just a few days in this manner. While it’s true that the least amount of time it takes to dry, the better for the final quality of your seaweed, it’s important to remember that anything your harvest yourself will be so incredibly fresh and superior to most herbs sold in the herbal industry. So don’t worry if it take a little while to dry!

Bladderwrack hung to dry on the line

Bladderwrack hung to dry on the line

Once it’s dry enough to snap when you try to break the fronds it’s ready to be stored. You can cut it into small pieces and store it in glass jars away from high heat and strong direct light. It can also be stored in durable plastic bags, like ziplocks. Since Bladderwrack is very oily in nature it has a shelf-life of about 6 months, after which it runs the risk of going rancid. To avoid this tragedy, simply store it in the freezer once you hit the 6 month mark and use as-needed.

Medicinal Use

Bladderwrack is in the family of Brown Seaweeds, which also includes Kelp, Wakame, and Kombu, and shares many of the same medicinal properties as these other seaweeds. It has a long history of medicinal use, being written about in all the old herbal texts. Due to it’s high Iodine content Bladderwrack is best known for its benefit for goiter and low/hypothyroid. In addition to Iodine it’s also rich in many minerals and trace minerals, including potassium, sodium, calcium, magnesium, sulfur, nitrogen, iron, zinc, boron, copper, manganese, chromium, selenium, bromine, vanadium, and nickel. It’s also extremely high in antioxidants and contains many of the B-complex vitamins, K, E, A, and D. Due to its super high mineral content Bladderwrack can be though of as a low-dose medicinal and food as medicine, since an excess of certain minerals can be harmful, and it’s also important to note it should not be taken during pregnancy or nursing.

Bladderwrack drying

Bladderwrack drying

Traditional dosage is about 3-6 grams/day. For a frame of reference, 1 tsp of the powder or a small handful of the fronds equates to about 3-4 g. In addition to being a superior nutrative, Bladderwrack  is rich in the polysaccharides fucoidan and algin, which have been widely studied and seem to be anti-cancer, anti-estrogenic, immune-boosting and strongly detoxifying. Studies link a diet that contains brown seaweed to strongly support cardiovascular health and lower rates of cancer. Bladderwrack also supports the muskuloskeletal system and has a history of helping folks with arthritis and injury, particularly when taken in a bath. Add ½-1 cup of the powder into a bath along with some epsom salts for a wonderfully relaxing and anti-inflammatory bath. For an idea on making your own inspired bath salts check-out my recipe and post on Mermaid Bath Salts! It’s also a nice soothing demulcent for irritations in the bladder, kidneys, and urinary system. In addition to taking the powder one can take the tincture (30-40 drops 2-4x/day), add it to a tea, make a cold infusion, and also use it in the kitchen. Bladderwrack can be added to broths and stocks, soups and stews (although it can take a while to cook until it’s tender), and the dried flakes can be sprinkled directly onto your food, added to traditional spice blends such as gomasio, furikake, togarishi, and so on!

Happy harvesting all!


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