The Santa Barbara Channel is nationally recognized as an incredibly diverse and biologically sensitive ecosystem. The Channel extends from Point Conception to Point Mugu, and is located in the Southern California Bight – an open embayment of the Pacific Ocean bound on the north by Point Conception and on the south by Cape Colnett in Baja California. The Bight extends offshore to the California current, a broad, southerly flowing current along the California coast. The four northern Channel Islands – San Miguel, Santa Rosa, Santa Cruz and Anacapa – border the Channel on the South. In 1980, Congress designated waters around the Northern Channel Islands as the Channel Islands National Marine Sanctuary.
The waters of the Santa Barbara Channel form one of the most biologically productive ecosystems found on Earth. Unlike most of coastal California, which faces due west and the open ocean, the coastal waters of the Channel are on a south-facing coast and caught between two land masses, the South Coast and the Northern Channel Islands. The western section of the Channel is a meeting place of the cool northern California Current and warm Southern California Countercurrent. This type of ecosystem is called a “transition zone.” Transition zones are known to promote large concentrations of both biomass and species diversity, as they are the confluence between two or more ecologically distinct systems. In addition, upwelling provides unusually high concentrations of nutrients, especially macrozooplankton, which are one of the primary driving forces behind the Channel’s biological productivity and diversity. Wind patterns around Point Conception and in the Channel create these frequent seasonal upwellings, which force deep, nutrient-laden ocean waters to rise up the water column into the biologically rich euphotic zone (the upper sunlight zone of the sea, less than 120 meters from the surface).
Due to these factors, the Santa Barbara Channel and Southern California Bight boast unparalleled species density and diversity, including numerous endangered, threatened and sensitive marine species such as blue, gray, and humpback whales, southern sea otter, southern steelhead, marbled murrelet and brown pelican. The blue whale, the largest mammal to ever live on Earth, maintains its highest recorded seasonal concentration of individuals in any of the world oceans around the Southern California Bight. The area is also home to acres of giant kelp beds that provide habitat for hundreds of marine species.
Due to this ecological richness, several state and federally protected marine areas have been created in the Santa Barbara Channel. There are 16 MPAs in the Channel (island and coastal), not including Santa Barbara Island. They range in size from more than 40 square miles (Richardson Rock Marine Reserve) to less than a quarter square mile (Goleta Slough Marine Conservation Area).
However, despite this protection, decades of pollution, over-fishing, coastal development, and other human impacts have left the precious marine habitats of the Channel in a degraded condition.
These waters and resources are especially vulnerable to the introduction of pollutants due to the presence of the Channel gyre. This gyre creates a somewhat closed system that is created by the Southern California Bight, Northern Channel Islands, and the confluence of the warm and cold ocean currents. The Channel gyre forms when the warm Southern California Countercurrent meets the much stronger, cold California Current, and the warmer current is forced into a counterclockwise rotational pattern that directs its waters south and eastward toward the Northern Channel Islands. Without the Channel Islands, these waters would flow out into the deep ocean. However, the Islands create a natural barrier which, depending upon season, ocean temperatures, and wind patterns, creates a huge counterclockwise rotating gyre in the entire Channel. Thus, pollutants tend not to escape into the larger Pacific Ocean, but instead disperse throughout the Channel ecosystem.