Page 278 - The Forager’s Guide to Wild Foods

Seaweeds and Marine Grasses ID

Seaweeds and seagrasses are grouped together here Care should be taken to forage sustainably. This in-
due to their marine environment. Seaweeds are not cludes leaving the holdfast undisturbed, not harvest-
flowering plants; they are multicellular macroalga ing large volumes of the reproductive structures, only
that have external fertilization (like a fern). Seagrass- cutting the top ⅓–½ of the frond and in most cases,
es are flowering plants, and have a root system and leaving the stipe intact.
internal fertilization. When harvesting air sacks or bladders, keep in mind
General Information that these sacks provide buoyancy to the seaweed to

ensure it gets enough light and is protected from being
All seaweed comes from 3 different types of macroal-
damaged on the rocks. Therefore, don’t strip all of the
gae, classified as: Brown Algae (Phaeophyta), Green
bladders off a single frond. Deep water “brown” spe-
Algae (Chlorophyta), and Red Algae (Rhodophta).
cies, such kelp, can be washed ashore after a storm.
Don’t let the color classification fool you. Many spe-
These fronds can be harvested as long as they are
cies classified as “red” may actually look brown, while
still fresh. When harvesting seagrasses, cut above the
while some “brown” species can look green.
sheath and do not disturb the rhizomes. If you happen
All known marine seaweeds are edible, but caution
to dislodge a piece, re-plant it like any terrestrial plant.
should be taken in brackish and freshwater areas.
Most species of green algae live in freshwater and are The Tidal Zone
toxic. Only the marine algae are edible, so ensure you The following terms are used to help describe where
only harvest in salt water. Seaweed absorbs nutrients in the shoreline you might find each species:
(including fertilizers, heavy metals, insecticides and • Splash zone only receives salt spray most of the
pesticides) from the water, so always harvest in unpol- year and is only inundated during storms.
luted water with no run-off from nearby agriculture. • High tide line is where the spring high tide reach-
Most seaweed species have a holdfast that secures es its maximum.
them to their substrate. The holdfast doesn’t absorb • Mid tide the mid-point between the high and low
any nutrients from the substrate. Most species are at- tide.
tached to rocks or man-made structures. Some may at- • Low tide line is where the spring low tide reaches
tach themselves to coral, shells or other seaweed spe- its minimum.
cies, while others float around the ocean completely • Subtidal zone is only exposed during rare extreme
detached. low tides.
Seaweeds have protection mechanisms. For example, Seaweed Nutrition
being slippery to the touch as well as being flat and Many factors can affect the quality and nutritional val-
flexible minimizes damage from the waves; having ue of seaweed. Season, water quality, salinity, water
segmented fronds and excellent rehydration abilities temperature, amount of sunlight, wave disturbance
helps them cope with being exposed at low tide. and large storms are just a few. The following general-
Vegetative reproduction is common in seaweeds. izations can be made:
Some have adapted to break off to colonize new areas. • All seaweed is high in salt.
Seaweed sexual reproduction involves specialized • Most seaweeds are high in anti-oxidants.
male and female structures that release their gametes. • When dried, seaweed is nutritionally dense.
These structures may take the form of extra blades, • Larger species of brown algae tend to contain more
bumps on their fronds, or round sacks or swellings. minerals and trace elements than red algae.
Harvesting Instructions • Kombu is incredibly high in potassium, magnesium
and vitamin K with plenty of other minerals.
The best time to harvest is when the tide is heading • Nori contains very high amounts of vitamin C which,
out. Start by walking out to the furthest point away and when eaten fresh, can help our bodies absorb more
work your way back to the shore. A good rule of thumb iron and other important minerals.
is to target rock pools that are abundant with life. • Most kelp species are high in magnesium and vita-
Most seaweed species spawn in May-June. Some can min K and have iron and calcium.
spawn as late as September in North America. Avoid • Wakame is high in most of the common minerals ex-
harvesting during or right after this event. cept for zinc.
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