I usually write about land plants, but this month I’d like to highlight those that dwell in the
ocean. Our coastal waters are home to a diverse variety of seaweeds, also known as macroalgae.
These remarkable organisms are deeply woven into culture, cuisine, medicine, cosmetics,
agriculture, and more.
Did you know that coastal Nova Scotians live in a Blue Forest Zone? The United Nations
Environment Programme (UNEP) has designated several such zones around the world —
underwater regions where plant life forms forest-like ecosystems. Five types of blue forests of
global significance include:

• Rockweeds
• Kelp
• Seagrass
• Salt Marsh
• Mangrove

For this article, I’ll focus on rockweeds, which grow abundantly along the shoreline near my
home in Head of Jeddore — and likely near yours too. A walk along our rocky eastern and south
shores at low tide will quickly reveal their presence.

Rockweeds share medicinal properties with many other seaweeds, such as kelp. They are best
known for supporting bowel function and relieving constipation. Their mucilage soothes irritated
mucous membranes in the digestive, respiratory, and urinary tracts. Due to their iodine content,
they may also support thyroid health. Applied topically, rockweeds can soothe itchy skin and
minor burns. Medicinal preparations include teas, infusions, tablets, and skin washes.

Other Uses of Rockweeds

Rockweeds are an important economic resource in Nova Scotia and throughout the North
Atlantic. Commercial harvesting began here in the 1960s, primarily for use in agriculture as a
fertilizer and soil conditioner. They’re also used industrially as thickening and gelling agents
in food products. Thanks to their high nutrient profile, rockweeds are included in animal feed as
well.

Rockweed Ecology

Rockweeds are essential to coastal ecosystems. According to researchers Johnson and Schiebling
(1987) and Seeley and Schlesinger (2012):

“Thirty-four species of fish, thirteen kinds of birds, and one hundred taxa of invertebrates have
been observed utilizing Ascophyllum as their habitat — some grazing directly on the seaweed
and its epiphytes, others seeking protection beneath its canopy.”

Rockweeds also help protect coastlines from erosion and flooding, and contribute to the ocean’s
carbon-sequestering capacity, supporting a healthier environment for both water and air.

How to Harvest Rockweed

Whether harvesting for personal use or commercially, we must prioritize sustainability to protect
this vital species and the ecosystems it supports. Here are a few responsible foraging tips:

• Harvest only rockweed that is attached to rocks, not seaweed washed up on shore.
• Choose clean areas, away from pollution and runoff
• Take only the outer tips — the fronds, blades, and air bladders — and leave the holdfast and main plant intact so it can regrow.
• Use scissors or snippers to avoid damaging the plant.

In Closing

I hope this article inspires you to look more closely — and more appreciatively — at the
rockweeds along our shorelines. Perhaps you’ll even try adding some to your next pot of soup or
enjoy a salty bite while beachcombing.

If you’d like to learn more about rockweeds and other local seaweeds, join me for Seaweed
Sunday, a workshop at my home on August 10, 1–5 pm. We’ll snorkel and wade through the
Blue Forest, exploring and sampling seaweeds in many forms. Click the button below to register for upcoming events.