As one of the Organizers of the North Shore Permaculture Group I am tasked with setting up meeting that promote all things permaculture. To this end I recently scheduled and a held a class on harvesting seaweed on May 17th. Now in New England Spring is often referred to as Mud for the amount of rain that we get. I started getting questions about what we would do if it rained on the day of the planned harvesting. My reply, “You get wet, so dress for the weather“! There were originally eleven people signed up for the class and we ended up with five of us hardy folk ready to grab this gift from the sea. I started out by explaining to the group about what seaweed that we would be encountering. It was slightly difficult as not only was it raining, but it was quite windy too.
Common name: Sea lettuce
Description: Ulva lactuca is a bright green sheet that closely resembles Monostroma spp. and Ulvaria spp. Ulva is two cells thick while Monostroma and Ulvaria are only one cell in thickness. Ulva can be differentiated from Monostroma and Ulvaria by the fingerprint test. If fingerprints can be seen through the translucent plant, it is Monostroma or Ulvaria. If they cannot, and the texture is similar to wax paper, it is probably Ulva.
The shape of Ulva is quite variable; some specimens are almost circular or oval while others are narrow and elongated. Plants have a fine, silky texture with waved or ruffled margins.
Habitat: Ulva is found in a variety of places-on exposed rocks, in tide pools, and in quiet shallow bays near the low tide mark. Ulva thrives in estuarine, nutrient-rich waters and may be dense in salt marshes and on mud flats where fresh water is abundant.
Foraging: Sea lettuce is an annual or a pseudo-perennial (most of the seaweed dies back and the plant is regenerated by a residual basal material). Young plants should be harvested in early spring for taste and tenderness. Blades are cut or plucked from rocks at low tide. Drifting plants may also be harvested if fresh.
Uses: Ulva is occasionally used fresh in salads, but is more often processed before eating. Ulva is prepared and eaten in the same manner as Porphyra (see page 14), but is not considered as much of a delicacy. Sea lettuce has also been used for burn treatments.
Processing: Sea lettuce may be washed in fresh water, drained, and dried for use as a seasoning (similar to Porphyra). It is also used fresh as a fodder or dried, milled, and added to animal feed.
Nutrients: Very high in iron. High in protein, iodine, aluminum, manganese, and nickel. Also contains starch, sugar, vitamin A, vitamin B1, vitamin C, sodium, potassium, magnesium, calcium, soluble nitrogen, phosphorous, sulfur, chloride, silicon, rubidium, strontium, barium, radium, cobalt, boron, and trace elements.
Knotted wrack (Ascophyllum spp.)
Rockweed, bladderwrack (Fucus spp.)
Description: There are several species of the genus Fucus, and one species of Ascophyllum with several different forms or “scads.” The Fucus species generally have dividing, Y-shaped, flattened blades with a prominent midrib. Fucus species may reach 2 or 3 feet in length and are not easily distinguished from each other.
Fucus vesiculosus has paired air bladders within the blades that “pop” when they are stepped on. These bladders keep the seaweed afloat so its photosynthetic tissues are more effectively exposed to sunlight. Breeding receptacles are football-shaped structures at the tips of the plant-orange if male and olive-green if female.
F. spiralis lacks bladders and has twisted fronds and numerous tufts of dark brown hairs scattered across the surface. Recep-tacles at the tips of the plants are “winged”–having a narrow, shelflike tissue bordering each one. F. distichus (subspecies edentatus, evanescens, and fileformis) are distinguished by the shape of their receptacles, which are 2 to 4 inches long and have a pointed tip.
Ascophyllum has long fronds without a midrib and narrow, unflattered, straplike blades with air bladders that grow singly and are scattered throughout the plant. Receptacles are small, pea-sized, yellow structures (found during the winter) along the length of the plant and attached by short stalks. A. nodosum has been reported to have a life span of about 20 years and is the dominant species of the sheltered and semi-exposed intertidal zone.
Habitat: These algae form the prominent “rockweed” zone of the intertidal region in northern New England. This is the generally dark brown area that is very slippery to those walking on rocky shores and ledges.
F. spiralis is found at the upper level of the intertidal zone, F. vesiculosus forms a band toward the middle, and F. distichus subspecies are found in tide pools in the high intertidal and extend into the shallow subtidal zone. Ascophyllum prefers shores protected from heavy wave action and may also be found in tidal pools of salt marshes. Some of the less common forms of Ascophyllum (i.e.. A. nodosum ecad scorpioides) are free-living, growing unattached and often entangled in Spartina salt-marsh grass.
Foraging: Ascophyllum and Fucus are perennials. Because they grow slowly, it is best to collect them after they have washed up on the beach after a storm.
Uses: The main uses of Ascophyllum and Fucus are as fertilizers, soil conditioners, and sources of micronutrients in animal feed supplements. Studies have shown that seaweed fertilizers promote plant growth by supplying necessary minerals and growth hormones, and by improving soil structure. Studies have shown that when these seaweeds are used in animal feed, cows produce more milk, chicken eggs have better pigmentation, and horses and pets are generally healthier. These seaweeds are also important packing materials for shipping live lobsters and marine bait worms. A special form of Ascophyllum called wormweed (A. nodosum ecad scorpioides) is a gold-colored seaweed with very fine fronds that grows in localized areas and is used exclusively for the sand and bloodworm bait industry.
Processing: Local farmers gather rock-weed for use as a fertilizer and soil conditioner, and simply bury it in their gardens. When used as an animal supple-ment, the algae are dried in commercial dryers to 10 to 12 percent water content and milled to various particle sizes. Some is processed into liquid fertilizer. Alginates are extracted chemically and used in bulking, gelling, and stabilizing processes. Products using alginates include charcoal briquettes, cosmetics, ceramics, cheese, paint, asphalt, rubber tires, polishes, toothpaste, ice cream, and paper.
Nutrients: Very high in magnesium, and high in protein, vitamin A, iodine, bromine, and phosphorous. Also contain sugar, starch, vitamin C, vitamin K, vitamin E, zinc, potassium, calcium, sodium, sulfur, chloride, silicon, iron, manganese, copper, zinc, cobalt, titanium, hydrogen, molybde-num, lead, barium, boron, radium, and trace elements.
Common names: Oarweed, kelp
Description: This brown kelp has a very long, narrow stipe (which may be 6 feet long) transforming into an elongated, flat blade with no midrib. The stipe becomes somewhat swollen and hollow before it joins the blade. Blades are fairly thick in the midsection, thin and a bit ruffled at the edges, and may be 6 to 30 feet long and very wide. Laminaria has a large branched holdfast. Plants range from olive-tan to olive-brown.
Habitat: A dominant plant of the coast, it grows in dense forests below low tide mark, from the shallow subtidal to deep water along much of northern New England’s shores.
Foraging: Peak harvest for Oarweed is in April and May. Blades are harvested by cutting with a knife or sickle at low spring tides.
Uses: These kelps are a prominent source of algin and food in the Oriental market. Traditionally they have been a source of iodine and potash. Their stipes were used to open wounds, aid in cervical dilation, and induce abortions. Oarweed is harvested in Maine for health food stores where it is sold as “kombu.” Prepared plants may be cooked as a vegetable or added to soups. As with the other kelps, oarweed is a natural source of monosodium glutamate.
Processing: Oarweed may be air- and sun-dried (or smoke-dried over a woodstove) and sold whole or milled and sold as seasoning.
Nutrients: High in calcium, potassium, magnesium, iron, and trace minerals such as manganese, copper, and zinc. Also provides chromium, instrumental in blood sugar regulation; and iodine, essential to the thyroid gland.
Common names: Laver, nori
Description: There are at least four species of Porphyra in northern New England waters: P. umbilicalis, P. miniata, P. Ieucosticta, and P. Iinearis. They are red algae, with color ranging from dark brown and nearly black to reddish-purple.
P. umbilicalis is most prominent with broad, very thin, papery, translucent blades, which are one cell thick. Its species name umbilicalis (meaning ‘of the navel”) comes from the fact that the small holdfast is usually centrally located and the membrane tends to have a pinched appearance where it joins the holdfast.
Habitat: P. umbilicalis is found in the upper and mid-intertidal zone on rocks and mooring balls in protected waters. P. miniata, a bright rose-colored species, is found at or below the low tide mark. P. Ieucostkta is smaller and usually grows on kelp fronds and rocks in the shallow subtidal zone. P. Iinearis is also small, has a narrow blade, and grows to be 2 to 3 inches long. It is found in turbulent, coastal waters in the upper intertidal zone.
Foraging: The peak harvest for Porphyra is early to mid-spring. Fronds are tough by summer. It is harvested by plucking the seaweed from rocks at low tide.
Preparation: Porphyra may be air-dried or pressed into thin sheets. To air dry, seaweed is washed quickly in cold, fresh water and hung on a clothesline or spread on screens to dry in the sun. Porphyra can also be toasted over a charcoal fire, broken up, and added to soups and sauces. For use in Japanese cuisine (especially for “sushi”), certain species of Porphyra are pressed and dried into paper-like, 3-gram (.11 ounce) sheets, 18 x 21 centimeters(7.09 x 8.27 inches) in size.
Uses: P. umbilicalis and P. miniata are air-dried and used in soups, in lever bread, and as a seasoning for many dishes. Some Porphyra species (such as P. Iinearis, which has a taste very similar to the Japanese species P. tenera) are commonly used as a wrapping for sushi, a Japanese dish. Nori has antiscorbutic properties (prevents and cures scurvy), is used as an antibiotic, and reduces blood cholesterol.
Nutrients: High in protein, vitamins B1, B2, B6, B1 2, vitamin C, and vitamin E. Also contains manganese, fluoride, copper, zinc, sugar, starch, and trace elements
Chondrus crispus Common name: Irish moss
Description:This red alga has large clumps of fan-like fronds, 3 to 7 inches tall. The fronds are flattened and may be narrow, branched, curled, or twisted. Several blades arise from a single holdfast and the tips of the blades are rounded. The color varies with locality and season, ranging from white, when washed ashore on beaches, to green and dark purple-red.
Habitat: Chondrus crispus occurs abun-dantly on rocks or horizontal ledges at or below the low tide mark and-in the shallow subtidal zone. It grows in sheltered, open coastal, and estuarine sites with strong tidal currents. It has also been found in water as deep as 60 feet.
Foraging: Irish moss is a perennial and is at peak for harvest in spring and summer. Harvesting in the summer is best for high vitamin A content. This seaweed is raked by hand at low tide from small boats or cut with sickles by wading out in shallow water. Storm-cast seaweed is often harvested from beaches.
Uses: As a source of the valuable carrag-eenan, this alga is of great commercial importance. When Chondrus is dried and boiled in water, carrageenan is extracted. Carrageenan is a gummy substance made of very large molecules that remain dispersed and suspended in liquids without settling to the bottom. It is used primarily as a thickener, stabilizer, and gelling agent in food and food products (jello, ice cream, salad dressings, chocolate and evaporated milk, pudding, frozen desserts, etc.), pharmaceuticals, toothpaste, cosmetics, paints, and textile sizings.
Chondrus was given its common name, Irish moss, because residents in County Carragheen, Ireland, discovered about 600 years ago that a handful of the seaweed cooked with milk and flavored made a delicious pudding. (See recipe for Irish moss pudding on page 27.) Irish moss gelatin (made by boiling the seaweed in water and straining it) has been used as a soothing remedy for ulcers.
Processing: Carrageenan is extracted by boiling the algae.
Nutrients: High in protein, vitamin A and iodine. Also contains sugar, starch, vitamin B1, iron, sodium, phosophorus, magne-sium, copper, calcium, soluble nitrogen, bromine, potassium, chlorine, sulfur, boron, aluminum, and trace elements.
Common name: False Irish moss
Description: False Irish moss is a small stiff plant, growing in tufts 2 to 3 inches tall with flattened and often curled blades. The terminal surfaces of the blades are covered with irregular “lumps” that enclose micro-scopic reproductive cells. It is usually dark red to brown in color and grows densely on rocks, forming a thick carpet.
Habitat: This seaweed, along with Irish moss, forms a distinct zone at the fringe of the low intertidal zone, between the rockweeds above and the kelp below. False Irish moss grows better on sloping and vertical rocky substrates, while Irish moss is more often found on horizontal ledges. Mastocarpus grows in areas of strong tides and minimal surf action.
Foraging: Mastocarpus stellatus is usually harvested incidentally with Irish moss.
Uses: Its major use is as a source of carrageenan. It has been used medicinally for coughs and chest and stomach ailments.
Processing: Like Irish moss, it is boiled and carrageenan is extracted from the aqueous solution.
Common name: Dulse
Description: Dulse is deep red or purple. The blades are flattened and broad with numerous forks. Lobed segments make the plant appear hand-shaped, thus its name palmata meaning “of the palm.” It has a tiny, disc-shaped holdfast and widens almost immediately into tough, leathery fronds. Dulse grows to 1 foot in length.
Habitat: This is a common red alga growing near or below the low tide mark in somewhat protected bays with strong tidal currents. It grows best on long sloping ledges. It is also commonly found growing on the stipes of kelps.
Foraging: Dulse is a perennial and is at peak for harvest from late spring to mid-fall. It should be collected in mid- to late summer for high vitamin A content and early to late fall for high vitamin C . It is harvested by cutting the plant from rocks at low tide.
Uses: Dulse is used exclusively for food.
Preparation: Dulse is simply spread out on the ground, air dried, and then packaged in plastic bags for distribution. It may be eaten directly as seaweed “chips” or added to soups, sauces, salads, and relishes. Some dulse is also dried and ground for use as a seasoning.
Nutrients: Very high in protein, iron, and fluoride and vitamins B6 and B12. High in potassium, iodine, and phosphorous. Also contains sugar, starch, vitamin A, vitamin E, vitamin C, soluble nitrogen, yeast, bromine, magnesium, sulfur, calcium, sodium, radium, boron, rubidium, manga-nese, titanium, and trace elements.
White, S. and M. Keleshian. 1994. A field guide to economically important seaweeds of northern New England. University of Maine/University of New Hampshire Sea Grant Marine Advisory Program. MSG-E-93-16. http://www.noamkelp.com/technical/handbook.html
This go around we were gathering for the garden but I did explain to the members that all of the plants were also edible for human consumption. This will be a meeting for another day. If one is gathering for that purpose it needs to be done when the seaweed is freshest and an optimal time would be after a storm.
I had checked the tide schedule and found that the low tide for May 17th at Hampton Beach NH was at 8:00 am. So I set the class for 8:30 to make sure that the gathering would not be compromised by the surf. The day was gray and in the beginning a driving rain which actually started to let up almost immediately. The location that I most often harvest from is at the end of the beach. Here is a line of rocks that prevents the tractors that clean the beach from entering. Which means that there is always plenty of seaweed for the taking. What we had harvested did not even make a dent to the piles. I had asked that the members bring empty buckets/containers to hold the seaweed. So there were many buckets to fill. All of which took about 15 min to finish off. It takes longer to get to the beach then it does to gather the seaweed. Then came the lugging of the heavy buckets back to the road and the loading up of the vehicles. It really is a simple as that!
I will reiterate here about how to harvest this seaweed. Do Not take the plants that are still attached to the rocks. You could do irreparable damage to tidal pools and sea life habitats. As you can see from the pictures there is no need to harvest in this way!
White, S. and M. Keleshian. 1994.A field guide to economically important seaweeds of northern New England. University of Maine/University of New Hampshire Sea Grant Marine Advisory Program. MSG-E-93-16. http://www.noamkelp.com/technical/handbook.html