Major Oceanic and Biogeographic Boundary
The Santa Barbara Channel is a transition zone between the cold waters of the California Current and the warmer waters of Southern California as shown in image of sea surface temperature (SST) to the right. Transition zones such as the Santa Barbara Channel may be particularly susceptible to shifts in the composition of marine species driven by climate fluctuations.
Pt. Conception (34.448 N, 120.471 W), at the western boundary of the Santa Barbara Channel, is a major biogeographic and coastal oceanic boundary that strongly influences the physical and biological dynamics of the marine ecosystems within the Channel. Much of the channel is considered a transition zone between the Oregonian and Californian marine faunal provinces. The plot of geographic ranges for marine intertidal species to the left exemplifies the dynamics of marine species distributions at Point Conception.
The mix of biogeographic provinces, warm and cool oceanic regimes and nearshore and offshore waters in the Santa Barbara Channel region results in a remarkably high biodiversity of marine organisms including marine mammals, seabirds, fish, invertebrates, plankton and algae. For example, at least 27 species of cetaceans have been recorded in the Santa Barbara Channel and 18 are considered resident, representing both northern and southern forms. Gray whales travel south through the channel in December and January, returning with calves on their northward trip from February to April as they migrate between feeding areas in the Bering Sea and breeding lagoons in Baja Mexico. The large pinniped rookeries of the northern Channel Islands currently support 4 species of seal and sea lions, including the California Sea Lion, Northern Elephant Seal, Harbor Seal,and Northern Fur Seal. Stellar's Sea Lion and the Guadalupe Fur Seal have also bred in the Channel Islands in past decades. Thousands of seabirds of eleven species have important nesting colonies on the Channel Islands. These breeding seabirds include southern species, such as the endangered brown pelican and northern species, such as Cassin's auklet.