While it’s true the Pacific Northwest is famous for its forests, there’s one we often overlook — the offshore kelp forest that thrives beneath the surface of our churning coastal waters. Easily its most impressive member, and the most common seaweed to wash up on our local beaches, is Nereocystis luetkeana, known by the more familiar names of bullwhip kelp, bull kelp, ribbon kelp, horsetail kelp, and sea otter’s cabbage.
Actually a complex algae (specifically, the largest in the family of brown algae), bullwhip kelp can be found from Monterey, California, to the Aleutian Islands in Alaska and grows in large fields in the subtidal zone. The fastest-growing kelp in the world, it is an “annual” seaweed, changing from a single spore in the spring to a mature plant by autumn. During the summer months, when growth peaks, it can gain up to 10 inches per day to eventually reach a length of 120 feet.
Nereocystis (Greek for “mermaid’s bladder”), clings to the rocky ocean floor with a holdfast, or rootlike structure, that keeps it tethered in place. From the holdfast grows a long stalk (called a stipe), that quickly becomes hollow as it reaches for the water’s surface. At the end of the stipe is the kelp’s airtight trademark bulb, which is filled with a gas containing carbon monoxide, and floats high in the water, keeping the kelp upright. Ribbon-like blades grow from the top of the bulb and spread out like hair across the surface of the sea, converting sunlight into food through photosynthesis.
Underwater, groves of bullwhip kelp provide shelter for crabs, snails, shrimp, sea stars, sea anemones, and many other marine invertebrates. On the surface, its flowing ribbons are popular with sea otters, who like to snack on the kelp and then wrap themselves in the tendrils to keep from drifting away in the currents while they sleep.
A complete source of trace minerals and protein, bullwhip kelp is entirely edible and has been harvested by humans for millennia. Indigenous people used the plant for food and also as a tool, weaving its long stipes into fishing lines and nets, and keeping the bulbs as storage for rendered fat and fish oil. Today, this kelp is still a prominent ingredient in many products, used especially to thicken ice cream, salad dressings, hand lotion and household paints. It is particularly delightful when pickled.