Where Does Bull Kelp Live?

Bull kelp can be found growing in a narrow band of the Pacific Ocean just off the coast of North America from Central California to the Aleutian Islands, Alaska.

Each region—each individual kelp grove—experiences specific conditions. We can compare and contrast bull kelp resilience and health across these regions.

Kelp Forest Index Diagram Mockup

The Kelp Forest Index

The species, or characters, in this kelp forest index, combined with ocean temperature and physical geography, create the dynamics that determine the health of the kelp forest in each region.

View Kelp Index Simulator >
A Coast-wide Species with Regional Dramas

In 1911 and 1912 a survey of the kelp beds along the coastal waters of the West Coast of the United States and Alaska was performed by the US Department of Agriculture. At the time, there were thoughts that the potassium content of kelp could make it a source of potash (used in explosives and imported exclusively from Germany) and jumpstart the nascent fertilizer industry. The kelp beds were surveyed from small dories put out by larger steam powered craft working their way from Southern California through Northern California, Oregon, Washington’s outer coast, Puget Sound and then, skipping Canada, they continued along the coast of Alaska, concluding in the areas around Kodiak Island. Each contiguous kelp bed was numbered and identified as either M (Macrocyists, or giant kelp), N (Nereocystis, or bull kelp) or M&N (a combination of both).

Josie Iselin

On those maps Nereocystis’s southern start point is bed No. 81 off Pt. San Luis (San Luis Obispo). For five months in 1987, Kathy Ann Miller was in the Aleutian Islands and went searching for the westernmost Nereocystis kelp bed which she established in a 1989 published paper at Umnak Island, 700 miles west of Kodiak, Alaska.

The various regions between these two endpoints of the bull kelp range offer different dramas playing out in the bull kelp forest. In fact, every bull kelp bed listed in the 1912 survey, every bull kelp bed from deep time and every bull kelp bed today has its own ecological spectacle playing out between the characters and conditions unique to its coastline, its bay or cove. These dramas can result in a range of conditions from kelp abundance to a desert ocean bottom covered in urchins, known as an urchin barren. 

We have chosen to investigate a collection of regions where these dramas play out differently to reveal more about the resilience and vulnerability of bull kelp, and to reveal more about us humans as either miners or growers of resilience. Each region highlights a fascinating aspect of bull kelp research or restoration, fisheries practices, or cultural relevance of this amazing kelp. Ecology is a hyper local enterprise in understanding, but there is much to be learned by looking up and taking stock of how bull kelp, sea otter, urchin, abalone, sea stars, ocean temperature, and human enterprise are playing out along the Pacific shores to the north or south of the beach or kelp bed that we call home.