About Kelp Forests

Kelp forests are composed of large brown algae that are characterized by large sizes and rapid growth rates. This highly productive habitat supports a wide variety of fishes, invertebrates, and marine mammals. Kelps are found in subtidal regions throughout the world where nutrients, light levels, temperatures and ocean currents permit. Marine grazers such as urchins, fishes, and snails can also limit distribution by overgrazing, particularly when predators are removed, which may allow herbivorous populations to boom.

Kelp forests grow predominantly along the Eastern Pacific Coast, from Alaska to Canada, to the waters of Baja California. These kelp forests are found in 4 of our National Marine Sanctuaries along the West Coast,and are dominated by two species. Giant kelp (Macrocystis pyrifera) and bull kelp (Nereocystis leutkeana).  Both of these species are found in California waters, however north along the coast in Washington waters, bull kelp is predominant.  What makes this macroalgae unique besides the ability to grow to heights of up to 200 feet, is that  there are airbladders known as a pneumatocyst that helps the plant float near the surface and gather more light for photosynthesis while shading out competitors. Giant kelp has  pneumatocysts on each blade(frond) while bull kelp only has one pnematocyst that supports several blades near the surface.

Watch our NOAA Fisheries video: Kelp Forests