It's surrounding waters serve as an invaluable nursery for the sea life that feeds larger marine mammals and seabirds. San Miguel is the westernmost island, strongly influenced by wind and weather. The colder waters here support a distinct group of fish and invertebrates that are not found on the southern islands. Santa Barbara Island is the smallest island within the Sanctuary and home of a large sea lion rookery and seabird nesting colonies. The tidepools are an area diverse with life forms.
Sea anenomes, shell fish, small fish, octopi, crabs, and algae are common residents.
The distribution of organisms is dependant on water level, temperature, and competition between species. Surfgrass is a critical member of the intertidal community providing a nursery habitat for many species of fish and invertabrates. Survival of the seedlings requires algae to enable root establishment. Once disturbed, it is difficult to regrow. Researchers at the University of California at Santa Barbara are exploring new techniques to help restore damaged surfgrass populations.