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Seaweed is an essential part of shallow
coastal ecosystems. It is to these marine
habitats as trees are to forests, providing
food and shelter to a variety of vertebrates
and invertebrates.
Contrary to popular belief, seaweeds
are not aquatic plants; rather, they are
considered algae. Algae do share some
similarities with plants. For example,
both organisms turn sunlight into sug-
ars through photosynthesis. However,
algae do not have the more specialized
tissues that plants do, such as xylem
and phloem. While the taxonomic
debate continues, for now we can say
that seaweed is not, strictly speaking,
a plant.
There are three main groups of sea-
weed: green, red, and brown. These
describe general trends in color, though
individual shades can vary, and many
“brown” seaweeds lean toward olive
green. They range in size from small,
lobed leaves growing like lettuce on
rocks, to large, narrow lancets that
can reach over one hundred feet long.
Each strand of seaweed grows from an
attachment point known as a holdfast,
which anchors it to a rock or other solid
object for life.
The easiest seaweeds to find are
those growing on or near the shore-
line. One of the most common here is
SEAWEED IS AN ESSENTIAL PART OF SHALLOW
COASTAL ECOSYSTEMS. IT IS TO THESE MARINE
HABITATS AS TREES ARE TO FORESTS, PROVIDING
FOOD AND SHELTER TO A VARIETY OF
VERTEBRATES AND INVERTEBRATES.
rockweed (Fucus distichus). This sea-
weed looks vaguely like a bundle of
lobed fingers, some with gas-filled
bubbles on the ends, and each with a
visible central vein. Feather boa kelp
(Egregia menziesii) looks very much
like its namesake, with many small,
thin leaves growing around a central
stipe (stem). Turkish washcloth (Mas-
tocarpus papillatus) is distinctive look-
ing, with rough-textured, wavy brown
leaves. You might even find laver/nori
(Porphyra spp.), which can look similar
to a plastic bag floating in the water.
This is the seaweed used to make sushi.
Finally, it’s hard to miss the bright
green of sea lettuce (Ulva spp.)
Some subtidal species may require
a boat if you want to get a good look at
them alive. Bull kelp (Nereocystis luet-
keana) is probably the best-known – a
single hollow stipe reaching upwards
of 120 feet in length, which terminates
in a gas-filled bulb. Several leaves
grow from this bulb, and some of these
can reach eleven yards long .
Most seaweed found on the Ore-
gon and Washington Coasts is native.
However, Japanese wireweed (Sargas-
sum muticum) is invasive. Thankfully
though, it’s edible, so the more you eat,
the more you remove competition for
native species. In fact, most of the sea-
weed species you’re likely to find in
the Pacific Northwest are edible.
Others, however, can be dangerous
to serve up. Witch’s hair (Desmares-
tia aculeata) can produce sulfuric acid
if damaged, which will ruin any other
seaweed it touches. Always be com-
pletely sure you know what species
you have before you harvest it, and that
it’s edible before you eat it.
In Oregon, you can only pick live
seaweed from March 1 through June
15, but you can harvest seaweed
washed up on shore any time. In the
latter case, you should be sure it is
very fresh, as it can rot quickly. The
daily limit is one gallon per person and
three gallons total per year. Also, each
harvester needs to bring their own con-
tainer. Seaweed must be harvested by
hand or with a knife, and no harvesting
is allowed in marine reserves or other
protected areas.
Washington has similar rules, with
a 10 pound per day limit per person (
seaweed must be weighed wet.) Sea-
weed may not be sold or bartered, and
you need a shellfish/seaweed license
to collect any amount for personal use.
Tools except for knives or scissors are
prohibited.
To harvest seaweed, cut or tear the
leaves away from the stem or holdfast.
Make sure to leave the holdfast intact
on its anchor so that it can grow back.
Seaweed needs to be washed thor-
oughly as it is often loaded with sand
— an initial wash in the ocean helps
remove small invertebrates that can
then be safely returned to the water.
Most edible seaweed can be eaten raw,
and more delicate species can lend
themselves well to salads. Seaweed can
also be dried, pickled, and even lightly
sauteed or stir-fried!
Rebecca Lexa is an Oregon Master
Naturalist, nature educator, tour guide,
and writer living on the Long Beach
Peninsula. More about her work may
be found at RebeccaLexa.com.
THURSDAY, FEBRUARY 17, 2022 // 5