Kelp and Shallow Rock Ecosystems (0-30 meters)



Kelp forests and shallow reefs are incredibly diverse and rich in life, hosting nearshore rockfishes, cabezon, greenlings, lingcod, anemone, red abalones, sea stars, and purple and red sea urchins. Many marine birds and mammals, including sea otters, also call this ecosystem home. With its shallower depths and diversity of marine life, this ecosystem is a popular snorkeling and scuba diving destination.


Kelp forests rise from the rocky substrate, forming canopies on the surface that function like a photosynthetic roof. Sub-canopy kelp species living in the mix of shadows and shafts of light that penetrate the canopy provide important habitat to fish and other species. Kelp forests along California’s coast typically include giant kelp, bull kelp, stalked kelp, and Stechell’s kelp. Rocky substrate below the kelp forest provide additional habitat for a diverse assemblage of species, as well as a sturdy settlement and growth for kelp and other algae.

Kelp forests are dynamic systems that can sustain ravage by storms and waves. Nutrient-rich upwelled water also causes natural increases or declines in kelp, affecting the fish and invertebrates that rely on kelp for food and shelter.


Baseline monitoring has increased our understanding of the structure and function of these ecosystems. Many nearshore rockfish inhabiting these ecosystems are long-lived – some species live more than 70 years and reach maturity at six to eight years of age. These inherent long life cycles increase the time to observe increases in population sizes that may follow MPA implementation. Anthropogenic influences on climate may contribute to changes in the frequency and intensity of storms, El Niño and La Niña events, and upwelling events. Changes in water quality due to human activities can also have sizable effects on these ecosystems.