Page images
PDF
EPUB

Figure 1. BOUNDARIES OF THE SANTA BARBARA CHANNEL REGION MARINE SANCTUARY NOMINATION AND PHYSIOGRAPHIC FEATURES OF THE REGION

[subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][ocr errors][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][merged small][merged small][graphic]

A fifteen mile boundary line has been carefully located to include the waters within the primary foraging radius of the California brown pelican, an endangered species, and other breeding seabirds on the islands, and to provide protection to the unique assemblages of bottom dwellers in the transition zone. This choice of boundaries in relation to the range of species and the location of habitats is in response to the legislative intent of the Marine Protection, Research and Sanctuaries Act, that a sanctuary's size should be that necessary to protect the values for which it was established. In addition, the size of the area responds to the functioning of the Channel region as a unit cally, hydrographically, and perceptually in the minds of those who exploit and enjoy its resources. Birds and mammals forage in several feeding grounds within the Channel and around the islands, although they nest and breed in a few specific places. Current circulate independently within the Channel, carrying nutrients and pollution with them throughout the Channel's waters. Actions in one location in the region can and do affect all other areas.

ecologi

The offshore island and basin topography of Southern California is unique in the North American continental shelf, and has created an uncommon diversity of habitats for the support of marine organisms. The west coast of cont intental United States is in one of the world's areas of upwellings, where the productivity of the oceans is concentrated due to the increase of nutrients available in the

water. The Santa Barbara Channel is a particularly important portion of these

waters because of its location as the focus of the California transition zone.

There are a handful of places in the world's oceans where two major marine provinces meet and intermingle. New species evolve or older ones survive in these places, greatly increasing their biological diversity. The combination of topography, upwellings, and transition zone dynamics have made the Santa Barbara

Channel a unique marine region by a definition of uniqueness that goes far beyond just a unique assemblage of organisms.

The uncommon diversity of habitats in the Channel region include the kelp beds, subtidal shelves, submarine ridges and canyons, rocky shores, sandy beaches, mudflats and estuaries, deep water basins, the unique habitats of the northern Channel Islands, and the slopes of the continental shelf facing the deep ocean. These provide an assortment of intertidal and bottom surfaces at different depths for marine plants and invertebrates, schooling areas for pelagic fish, nesting and roosting locations for seabirds, and haulout and breeding grounds for seals and sea lions. The productivity of the island platform and the mainland shelves sustain not only resident species, but thousands of migratory animals as well.

Point Conception at the west end of the nomination area provides a major biogeographical break of the eastern Pacific, where the coastal species composition change relects the change in ocean temperature characteristics. Extensive upwelling along the central and northern California coast contributes large amounts of rich, cold water to the south-moving California Current. At Point Conception, where the coast turns abruptly eastward, the California Current meets the warmer southern waters brought north by the geostrophic current. These 'rivers in the sea' carry with them the organisms of two distinct Pacific ecosystems, the northern and southern faunal provinces. The results of these two current patterns are that San Miguel and the western half of Santa Rosa are bathed by the cold California current, with flora and fauna characteristic of northern climes. Santa Cruz, Anacapa, and the eastern half of Santa Rosa reCalifornia Current water and warm counter current water. The

ceive both cold

highly significant consequences are a very rich flora and fauna with much div

1

Figure 2. VALUES AND RESOURCE AREAS OF THE SANTA BARBARA CHANNEL REGION

[ocr errors][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][subsumed][merged small][ocr errors][graphic]

ersity and many species characteristic of the north and the south.

The richness of the transition zone ecology is enhanced by the presence

of upwellings internal to the Channel. Prevailing offshore winds carry surface waters seaward, carrying colder, nutrient-rich waters from moderate depths to the surface. Areas of upwellings are three times as productive as the coastal zones in general, and six times as productive as the open ocean. One indication of the abundance of this combination of transition zone and upwellings in the Channel area is the high number of predator species (including man) feeding at the top of the food chain, more than in any other upwelling region in the world.

Nutrients from upwellings, directly supply the phytoplankton, the primary producers of ocean food chains. But the Santa Barbara Channel also has some of the densest stands of giant kelp, the immensely productive 'forests of the sea', whose rates of production are comparable to tropical forests, and have been measured at over ten times the annual production of phytoplankton in temperate waters. Over 800 plant and animal species are known to be associated with these beds, including many valuable sport and commercial species. In the last ten years, some of the major beds south of the Santa Barbara Channel have all but disappeared due to temperature changes, sewage discharges, and kelp grazers. Neushul at the University of California, Santa Barbara, points out that the Channel beds are the most productive natural beds in Southern California and are likely to be the most productive in the northern hemisphere along this coast.

Thousands of different species of birds, seals and sea lions, whales, invertebrates, fish, and marine plants depend on the habitats of the Channel area These include eighteen rare and endangered animals in the Channel or utilizing one or more of the islands, and six rare and endangered coastal plants. (See chart.) Thirty marine mammals are known for the area

for support.

six kinds

« PreviousContinue »