Seaweed Splendors

Spring brings warmer and longer days, and suddenly our local beaches are festooned in brilliant red and green seaweeds and brown kelps. “When the tide goes out, the table is set.” This astute observation comes from Pacific Northwest’s First Nations people’s traditions of foraging for shellfish and kelp during low tide. In Washington aficionados update their annual license from the Department of Natural Resources (DNR) to harvest seaweed and kelp. I hope they all follow the clear limits and proper conservation methods required by DNR. Here are some photos of native animals in our area that depend on seaweeds in a variety of ways. At the end are photos from a friend who interacts with seaweed artistically.

Columbian Black-tailed Deer

As long as people aren’t walking on the beach, our fearless Port Townsend deer enjoy nibbling on seaweeds such as green sea lettuce (Ulva species). Sea lettuce is nutritious because it’s rich in vitamins, minerals, and protein. It’s one of 130 green seaweeds in the Pacific Northwest, all growing in seawater and included in the Plant Kingdom.

Brant 

Brant geese prefer eelgrass, and when it’s not available, sea lettuce is their next favorite food. Hundreds gather along the shores of Point Hudson and Fort Flagler every spring to fatten up and prepare their bodies for the long flight north to breed. Four years ago I wrote more about the beautiful Brant, one of my favorite birds: https://rainshadownorthwest.com/2022/04/10/beautiful-banded-brant/

Mallard

Are you surprised to see a Mallard eating seaweed on the beach? Don’t they just eat seeds, grains and maybe snails? They’re actually considered generalist foragers, and since they’re “dabbling” ducks, just like Brant geese they aren’t able to dive for food. Aquatic vegetation is an important part of a Mallard’s diet.

American Wigeon

Another lovely dabbling duck is the American Wigeon. A male (left) and female (right) are wading at low tide by the ferry terminal to search for seaweed. These ducks spend winters along our coast eating plants, both aquatic and terrestrial. Soon they will fly north to breed.

American Crow

The American Crow isn’t eating sea lettuce here; it’s strutting about seeking tiny crustaceans that live among the seaweeds that are exposed at low tide. Often crows and shore birds grab seaweed and shake it or flip it aside to find a small critter such as an isopod or juvenile crab. 

Common Raccoon

Clever Raccoons are considered opportunistic omnivores, and they dig into masses of kelp to discover a tasty meal. We have 23 kelp species in the Pacific Northwest, some of the highest kelp diversity in the world due to cold waters and currents. It’s fascinating to learn that unlike red and green seaweeds, kelp is not included in the Plant Kingdom and is now placed in the Chromista Kingdom along with Dinoflagellates, a marine plankton. This raccoon is enjoying a High Cockscomb, a fish that can breathe air and survive being out of the water during a low tide, as long as it stays moist in seaweed. And… as long as it avoids raccoons and other predators.

North American River Otter

The North American River Otter is another predator of the High Cockscomb and other fishes hiding in the seaweed. This one may be a gunnel or another “eel-like fish.” Unlike raccoons, river otters don’t use their paws to consume their prey. It’s rather remarkable how they can tear apart a large fish or crab using only their teeth.

Northern Kelp Crab

The Northern Kelp Crab lives among kelp and blends into a kelp forest since it’s usually the same brown color. Not only does kelp help it hide from predators, but it’s what these crabs eat. And in this case, it used sugar kelp (and sea lettuce) to decorate its carapace for even better camouflage!

Graceful Decorator Crab

Other crabs use seaweeds as decoration for camouflage. Locally the Graceful Decorator Crab is the master, sometimes completely covering itself so you can’t see any part of its carapace at all. This crab chose a few red and green seaweeds and bits of kelp to cover its legs. We have 370 species of red seaweeds in the Pacific Northwest. To fully cover the long rostrum between its eyes, it chose only red seaweeds.

Bull Kelp

Bull Kelp is probably our most familiar, an astonishing kelp that can grow up to 118 feet long in one year, and it only lives for one year.  How does it survive the waves and currents? It needs to attach to a sturdy rock using its holdfast, which looks like clasping roots, allowing its long stipe and blades to reach upwards and its pneumatocyst to float on the surface during a high tide. In this sad case, three young Bull Kelp made a poor choice; their holdfasts all grabbed a small plate limpet. On a stormy day, the limpet was torn from its own home on a boulder, and they all washed ashore.

Seaweed Education

Nam Siu, a biologist with the Washington Department of Fish and Wildlife (WDFW), leads educational walks, including this “Searching for Seaweed” workshop last spring for WSU Extension to teach identification of seaweeds and kelps on our beaches. Every class Nam teaches fills up because he’s so knowledgeable, as he’s a scuba diver, and now works in the WDFW Shellfish and Seaweed Health and Biosecurity unit.

Seaweed Pressing 

Finally… seaweed and its beauty. Nam Siu is also a seaweed artist who shares his methods for pressing species to preserve their beauty. Here’s his spectacular pressing of two Desmarestia species. Although beautiful, these are never to be consumed due to their toxicity. They emit sulphuric acid to protect themselves from predators. At the same time they bleach themselves and any other seaweeds they contact, by summer creating the appearance of army camouflage on the beach. 

Another Pressing

You can see more of Nam’s artwork here: https://www.instagram.com/spearotaku/. When you walk along beaches this spring pause to appreciate the beauty, variety, and complexity of our Pacific Northwest seaweeds and kelps. Don’t worry about identifying them, though if you want you can join me in using iNaturalist!