Sea Lettuce (Ulva spp.)

Description: Sea lettuce - a type of green algae - is one of the most commonly found species of seaweed, typically seen in tide pools attached to rocks. Sea lettuce is what one may imagine when they think of a typical seaweed: it grows in thin strips or blades, it averages about 20 cm (closer to 50 cm for U. taeniata) in length, and its color varies in shades of green. Sometimes it’s more pale, but often it is a vivid, bright green. There are three main species found in our tidepools. Common sea lettuce (Ulva lactuca) is arranged in broad blades with a sometimes ruffled edge. Corkscrew sea lettuce (Ulva taeniata) has elongated blades arranged in a spiraled corkscrew. Sea hair (Ulva intestinalis) comes in bunches of thin, hollow tubes.

Habitat: Its geographic range spans from northern Alaska down to California along North America’s Pacific Coast. It’s also found along the coastlines of China, Japan, Korea, and Russia.  

Tide Pool Tidbits:

• Sea lettuce is edible and can either be eaten fresh or dried. It is often added to sushi, soups, or stews and only needs a small amount to add a lot of flavor.

• When this seaweed is reproductive, it often appears lighter in color, closer to a yellow or pale-green. It may also be bleached white or translucent when exposed to too much sun.

• Species of Ulva are very thin, some only one or two cell layers thick!

Reference: The New Beachcomber’s Guide to the Pacific Northwest by J Duane Sept