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Site History and Resources

Overview

Computer imagery shows the topography of the seafloor of Gulf of the Farallones National Marine Sanctuary and the steep drop-off of the continental slope west of the Farallon Islands. (Image: USGS Woods Hole)
Figure 1. Computer imagery shows the topography of the seafloor of Gulf of the Farallones National Marine Sanctuary and the steep drop-off of the continental slope west of the Farallon Islands. (Image: USGS Woods Hole)
Gulf of the Farallones National Marine Sanctuary protects an area of 1,279 square statute miles (966 square nautical miles) off the north-central California coast. The sanctuary was designated in 1981 because of its national significance as an area that encompasses a diversity of highly productive marine habitats and supports an abundance of species. The sanctuary is administered by the National Oceanic and Atmospheric Administration (NOAA), within the Department of Commerce.

Figure 2. A view of the sanctuary from the Farallon National Wildlife Refuge. (Photo: J. Hall, GFNMS)
Figure 2. A view of the sanctuary from the Farallon National Wildlife Refuge. (Photo: J. Hall, GFNMS)
The Gulf of the Farallones sanctuary comprises a wide spectrum of marine habitats including sandy beaches, estuaries, rocky intertidal zones, and deep-ocean environments. The sanctuary is marked by a gently sloping seafloor extending for nearly 35 miles (30 nautical miles) from the mainland before dropping off steeply at the Farallon Escarpment beyond the Farallon Islands, and lies within the widest portion of the continental shelf along the California coast (Figure 1).

The Farallon Islands (Figure 2) are located in the south-central part of the sanctuary, 27 miles west of the Golden Gate Bridge. The islands are a national wildlife refuge administered by the U.S. Fish and Wildlife Service. They offer resting and breeding sites for pinnipeds and seabirds that are lured to the region by waters rich in plankton and fish. The sanctuary is home to thousands of seals and sea lions, and the largest concentration of breeding seabirds in the contiguous United States.

Figure 3. The wetlands of the sanctuary, like Estero Americano, stretch up to nine miles inshore and provide important habitat for birds on the Pacific flyway. (Photo: T. Yarrish)
Figure 3. The wetlands of the sanctuary, like Estero Americano, stretch up to nine miles inshore and provide important habitat for birds on the Pacific flyway. (Photo: T. Yarrish)
Several coastal embayments including Bolinas Lagoon, Bodega Bay, Drakes Bay, Estero Americano, Estero de San Antonio and Tomales Bay (Figure 3) are located within the Gulf of the Farallones sanctuary. Bolinas Bay, Drakes Bay, Tomales Bay and Bodega Bay are open to the ocean, but are somewhat protected from prevailing southward moving coastal currents by Duxbury Point, Point Reyes Headlands and Bodega Head, respectively, and are important plankton retention areas. Tomales Bay and Bolinas Lagoon, which occupy valleys directly on the San Andreas Fault, have been designated by the United Nations as "Wetlands of International Significance." The shoreline along the mainland coast is characterized by sandy beaches and rocky cliffs.

Figure 4. The Gulf of the Farallones is one of three contiguous national marine sanctuaries located along California's northern and central coast. The Gulf of the Farallones sanctuary is responsible for administration and management of the northern area of the Monterey Bay sanctuary extending from the San Mateo/Santa Cruz county line northward to the existing boundary between the two sanctuaries. (Map: T. Reed, GFNMS)
Figure 4. The Gulf of the Farallones is one of three contiguous national marine sanctuaries located along California's northern and central coast. The Gulf of the Farallones sanctuary is responsible for administration and management of the northern area of the Monterey Bay sanctuary extending from the San Mateo/Santa Cruz county line northward to the existing boundary between the two sanctuaries. (Map: T. Reed, GFNMS)
In addition to the area within the boundaries of the sanctuary, the Gulf of the Farallones sanctuary is responsible for administration and management of the northern area of the Monterey Bay sanctuary extending from the San Mateo/Santa Cruz county line northward to the existing boundary between the two sanctuaries (Figure 4). Some areas of the Gulf of the Farallones sanctuary are influenced by conditions and features within the northern portion of the Monterey Bay sanctuary; therefore, this document considers these influences when determining the status of the water quality, habitat, living resources and maritime archaeological resources within the Gulf of the Farallones sanctuary.
Regional Cultural History

During the Pleistocene/Holocene Epoch, about 11,000 years ago, the Central California coast was inhabited by the Paleo-Indian people at coastal sites that have long since been inundated by rising sea level. By about 8,000 years ago, the Archaic cultural shift occurred in which people became less migratory and settled in established villages. Archaeological evidence (e.g., fishbone and shellfish remains) from this time period indicates that some coastal groups relied more on resources of lagoon marine environments, and hunting of marine mammals declined in importance. Between 5,500 and 1,000 years ago, intense harvesting and processing of shellfish became more important as a food-gathering activity (Terrell 2007).

The indigenous people who lived in the Marin County and coastal Monterey Bay regions about 4,000 years ago were of the Penutian linguistic group, related to the Inland Miwok. The Miwok lived along the coast of San Francisco Bay to about five miles north of Bodega Bay, near the coast and along the lagoons in conical, thatched huts that could hold as many as 10 people. The 18th-century encroachment of the Spanish into the region, who set up missions to Christianize the natives, radically changed the native people's culture (Terrell 2007).

The Spanish first explored Central California's coast in 1542. Thirty-seven years later, England's Sir Francis Drake challenged Spanish authority in the Pacific as he explored the coast and raided Spanish possessions. Upon stopping to careen1 his ship, Golden Hind, on the beach that research suggests is now known as Drakes Bay, the natives greeted the scurvy-ridden crew with gifts of salmon, sturgeon and mussels. Drakes Bay has a rich maritime heritage, most significantly the 1595 Manila galleon San Agustin, the oldest known shipwreck on the West Coast and one of the earliest points of European contact with indigenous populations (Terrell 2007).

By the 1770s, the Spanish had realized the importance of occupying California and had established a presidio and three missions around San Francisco Bay. In 1775, Lt. Francisco de La Bodega y Quadra found and named Bodega and Tomales Bays.

The Russians provided the greatest immediate threat to the Spanish empire in California. Hunting otter for furs in Alaska in the early 1700s, Russian trappers gradually worked their way down the northwest coast, and by 1812 they had established a permanent base north of San Francisco (Terrell 2007).

Figure 5. An aerial view of the South Farallon Islands, surrounded by Gulf of the Farallones National Marine Sanctuary. In 1909, the Farallon Islands were designated as the Farallon National Wildlife Refuge, with the exception of the Southeast Farallones, which were added in 1969. (Photo: J. Roletto, GFNMS)
Figure 5. An aerial view of the South Farallon Islands, surrounded by Gulf of the Farallones National Marine Sanctuary. In 1909, the Farallon Islands were designated as the Farallon National Wildlife Refuge, with the exception of the Southeast Farallones, which were added in 1969. (Photo: J. Roletto, GFNMS)
Mexico's independence from Spain, won in 1821, altered California's social and economic landscape. While many Spanish and Mexican nationals settled into the privileged life of ranch owners (rancheros), many foreigners - especially Yankee traders and American expatriates - settled in the community that formed in Yerba Buena, which later became known as San Francisco. The Mexican government temporarily opened California's ports to foreign vessels in hopes of generating revenue from import duties, and foreign fur traders were soon joined by hide and tallow traders and whalers (Terrell 2007).

San Francisco became a preferred base for whaling ships. The Orion was the first of these to arrive in San Francisco Bay in 1822, and soon dozens of whaling ships were plying the Pacific, using San Francisco as a provision and rest stop. The whalers also stopped at the Farallon Islands to obtain fresh water and meat (Figure 5), and it is likely that the islands served as the whalers' base for smuggling and illegal trade. The abuse of trading privileges prompted the Mexican officials to reinstate trade restrictions in the 1830s and threaten more vigorous enforcement during the 1840s.

Figure 6. Ships in Yerba Buena Cove, San Francisco during the gold rush 1849 – 1850. (Image: Library of Congress)
Figure 6. Ships in Yerba Buena Cove, San Francisco during the gold rush 1849 - 1850. (Image: Library of Congress)
By the 1830s and 1840s, the United States, England and France held a strong interest in the purchase of San Francisco Bay. A large American force remained in what was then known as Alta California until early 1843, and warships visited the Bay Area between 1844 and 1845. In 1846, war with Mexico brought about a bloodless conquest of Alta California by Commodore John B. Montgomery of the USS Portsmouth. In spring 1847, three U.S. military transports carrying nearly 600 volunteers passed through the Golden Gate to colonize the new territory. The American territory did not have to wait long for the population to grow. Following news of the gold strike at Sutter's Mill on the American River, thousands arrived to seek their fortune in the gold fields. After the 1848 gold strike, hundreds of vessels of varying size, rig and registry sailed or steamed into San Francisco Bay (Figure 6).

Several other economic activities developed in the wake of the Gold Rush. During the Native American (approximately 10,000 years before present to the 18th century), Spanish (late 18th century to early 19th century), and Mexican (1821 - 1846) periods, fishing was small-scale and usually conducted by Indians for personal consumption. Following the Gold Rush, the fishing industry grew rapidly along the coast in order to feed a growing population. The first to become involved in an intensive fishing industry in Central California, the Chinese established fishing villages and camps at Point San Pedro (San Pablo Bay), Rincon Point (San Francisco Bay), and Tomales Bay. By the end of the 19th century, Genovese fishermen from San Francisco commercially fished at Drakes Bay for herring, oysters (native and introduced), salmon, crab, perch, striped bass (introduced), rock cod, tuna and sardines. Other immigrants who fished out of the San Francisco region included Italians, Greeks, Portuguese and Yugoslavians. San Francisco, and smaller coastal harbor towns to the north, developed through fishing, shipping and economic exchange. As San Francisco grew, an inter-coastal trade grew between the bay communities and other coastal regions such as Bodega and Tomales Bays and Point Reyes. Dairy ranches replaced Mexican ranchos north of San Francisco, while privately owned ranches on Tomales Point and Point Reyes produced butter and hogs for San Francisco's population (Terrell 2007).

By 1935, San Francisco was the home port of 20 American steamship lines, with more than 40 foreign lines also maintaining offices and agents in the city. More than 500 ships called every month of the year, and the majority of those ships purchased supplies from San Francisco merchants. The Port of San Francisco's Fisherman's Wharf soon became the center of Northern California's commercial and sport fishing fleets. Today, the wharf's Pier 45 houses the West Coast's largest concentration of commercial fish processors and distributors. The most important commercial harvests include Pacific herring, salmon, rockfish, flatfish, albacore tuna and Dungeness crab. Most of the commercial catches are landed in Bodega Harbor, San Francisco, Oakland, Sausalito and Half Moon Bay. A number of mariculture operations in Tomales and Drakes bays raise native and non-native oysters.

The population around San Francisco Bay has grown rapidly and now exceeds 7 million people. The Bay Area's economy ranks as one of the largest in the world, larger than that of many countries. More than 10 million tourists visit the Bay Area each year (Chin et al. 2004). The Presidio is now home to the main offices of the Gulf of the Farallones sanctuary staff.

Designation of the Sanctuary

In 1981, the Gulf of the Farallones sanctuary was designated in response to the concerns of local environmentalists, fishermen and researchers about oil drilling in the Gulf. Of particular concern was the threat of major oil spills polluting the waters and damaging the resources on and around the Farallon Islands and Point Reyes (a peninsula located north of San Francisco Bay), which are home to or migratory feeding grounds for more than 500,000 coastal birds and seabirds and thousands of marine mammals. The sanctuary was originally designated as the Farallon Islands-Point Reyes National Marine Sanctuary, and later the name was changed to Gulf of the Farallones National Marine Sanctuary to reflect the body of water it protects.

In 1992 the Monterey Bay sanctuary was designated. It is located immediately south of the Gulf of the Farallones sanctuary and covers 6,094 square statute miles (4,602 square nautical miles) of ocean and coastal waters (see Figure 4). The Gulf of the Farallones sanctuary is responsible for administration and management of the northern area of the Monterey Bay sanctuary extending from the San Mateo-Santa Cruz county line northward to the existing boundary between the two sanctuaries.

Sharing Boundaries
Three of the 13 marine sanctuaries have contiguous boundaries. Cordell Bank, Gulf of the Farallones and Monterey Bay national marine sanctuaries all are situated within a coastal marine ecosystem dominated by the California Current (see Figure 4). While each has distinct features and settings, some resources are similar and move freely between the sanctuaries. Therefore, site management is not always determined by site boundaries. Staff of the three sanctuaries share responsibilities for research, monitoring, education, enforcement, management plan development and other activities required to protect the region's natural and cultural heritage resources. For more information on the status and trends of resources within the Cordell Bank and Monterey Bay sanctuaries, please visit the Office of National Marine Sanctuaries Web site.

Geology

The Gulf of the Farallones sanctuary is marked by a gently sloping seafloor of the continental shelf that extends westward for nearly 35 miles offshore before dropping off abruptly to depths of 6,000 feet west of the Farallon Islands (Karl and Schwab 2001). This large underwater expanse is the widest portion of the continental shelf along the Oregon and Northern California coasts and is primarily characterized by large underwater sand dunes with surface ripple marks. Sanctuary sediments are generally quite coarse and are dominated by sand, except for silty regions north of Point Reyes, on the continental slope, and in the mid-shelf region off the San Mateo County coast (Edwards 2002 and Karl 2001). The shelf break and slope have a thin veneer of sediment surrounding patches of rock outcroppings.

The Farallon Islands lie along the outer edge of the continental shelf roughly west of San Francisco and south of Point Reyes. The islands and the rest of the Farallon archipelago are part of a larger submarine ridge that extends for approximately 10 nautical miles and includes South, Middle and North Farallon islands, Hurst Shoal, Fanny Shoal, Noonday Rock, Rittenburg Bank, and Cordell Bank. Other rocky outcrops and areas of highly variable local bottom-relief are found along the Farallon Escarpment, in Deep Reef (offshore of Half Moon Bay and San Gregorio, within the Monterey Bay sanctuary), in the area off Pescadero Point, and at the head of Pioneer Canyon. Areas of variable relief and rocky substrate are often associated with significant ecological richness, spawning and feeding areas, and high species diversity.

Figure 7. The San Andreas Fault Zone system within the Gulf of the Farallones region. The northerly motion of the Pacific plate, relative to the North American Plate, led to the formation of the San Andreas Fault system. (Map: T. Reed, GFNMS)
Figure 7. The San Andreas Fault Zone system within the Gulf of the Farallones region. The northerly motion of the Pacific plate, relative to the North American Plate, led to the formation of the San Andreas Fault system. (Map: T. Reed, GFNMS)
Well-known for the 1906 San Francisco earthquake, the San Andreas Fault Zone separates the Pacific and North American Plates and runs through the eastern Gulf of the Farallones sanctuary (Figure 7). Tomales Bay, Bolinas Lagoon and Bodega Bay are located directly on the San Andreas Fault. The northwestward movement of the Pacific Plate (on the west) relative to the North American Plate (on the east) causes earthquakes along the fault. Most of Marin County is located on the North American Plate, while Point Reyes, the Farallon Islands and Bodega Head are part of the Pacific Plate.

The coastline within the Gulf of the Farallones sanctuary includes sandy beaches, rocky cliffs, open bays (Bodega Bay and Drakes Bay), enclosed bays or estuaries (Bolinas Lagoon, Tomales Bay and Bodega Harbor), and seasonally closed lagoons (Estero Americano and Estero de San Antonio). Sediment washed into the sanctuary by rivers and from shoreline erosion predominantly during the winter storm season is distributed throughout the sanctuary by currents year-round. Beach sand is moved down-coast from beach to beach by the process of longshore drift, with seasonal deposition and erosion changing the width and steepness of beaches, winter to summer. The two Esteros become closed off from the ocean during summer and fall by seasonally formed sand bars. Tomales, Bolinas and Bodega, however, remain open to the ocean year-round.

Water

Figure 8. Schematic of major oceanographic features off the north-central California coast: Blue zones indicate upwelling centers that may be localized at capes (Point Arena, Pigeon Point) or expand along much of the coast), while blue arrows indicate plumes of upwelled waters moving south and offshore from upwelling centers. Green arrows indicate plumes of San Francisco Bay outflow, moving either south (during upwelling) or north (during weak winds or winter). Strong winter outflow from rivers like the Russian and Gualala is demarcated by brown arrows. Not shown is the retention zone in Drakes Bay and smaller zones in Bodega Bay and Half Moon Bay. These schematic patterns change with the wind, land runoff, seasons and years. (Sources: MLPA Regional Profile: J. Largier, Bodega Marine Lab, and The Ocean Conservancy 2007)
Figure 8. Schematic of major oceanographic features off the north-central California coast: Blue zones indicate upwelling centers that may be localized at capes (Point Arena, Pigeon Point) or expand along much of the coast), while blue arrows indicate plumes of upwelled waters moving south and offshore from upwelling centers. Green arrows indicate plumes of San Francisco Bay outflow, moving either south (during upwelling) or north (during weak winds or winter). Strong winter outflow from rivers like the Russian and Gualala is demarcated by brown arrows. Not shown is the retention zone in Drakes Bay and smaller zones in Bodega Bay and Half Moon Bay. These schematic patterns change with the wind, land runoff, seasons and years. Click here for a larger image. (Sources: MLPA Regional Profile: J. Largier, Bodega Marine Lab, and The Ocean Conservancy 2007)
The Gulf of the Farallones sanctuary is located in the California Current, one of the world's four major wind-driven upwelling systems, the other three systems being located along the west coasts of South America, southern and northern Africa (Gross 1972 and GFNMS 2008b) (Figure 8). Northerly winds drive a shallow surface layer that moves offshore due to the Coriolis effect. This offshore (Ekman) transport of surface waters results in the upwelling of cold, nutrient-rich waters from depth into sunlit surface waters to support a food-rich environment and promote the growth of organisms at all levels of the marine web. Upwelling may be widespread at times, or localized at upwelling centers (e.g., Point Arena). In addition to upwelling, San Francisco Bay may be an important source of nutrients and organic matter in the Gulf of Farallones. The result is that high concentrations of phytoplankton are observed in the Gulf of the Farallones near the water surface, making them available to zooplankton and higher trophic prey species such as krill, whales, fish and birds. In addition to upwelling-driven productivity in bays, estuaries and other nearshore environments during spring and summer, seasonal blooms may occur in response to rainfall and runoff in other seasons.

Habitat

Within the Gulf of the Farallones sanctuary is a wide spectrum of marine habitats including sandy beaches, estuaries, bays, rocky intertidal zones, shallow continental shelf (consisting of hard and soft bottom habitats), islands, deep slopes and offshore waters. While the nearshore habitats are fairly well characterized, offshore habitats are not.

Many sandy beaches are found along the coastal border of the Gulf of the Farallones sanctuary. Numerous invertebrate communities can be found in these habitats, which are used as breeding grounds by many birds and pinnipeds. Sandy beaches are dynamic environments, constantly changing under the influence of ocean waves. Detached plant and algal debris and corpses of fishes, seabirds, and marine mammals influence the structure of sandy beach communities by providing food and shelter that are otherwise not available.

Small sandbar-built estuaries with seasonal inflow dominate the California coast due to the steep coastal topography, seasonal rainfall and seasonal higher wave energy conditions. However, one major estuary is found adjacent to the sanctuary: San Francisco Bay, consisting of Suisun Bay, Suisan Marsh, San Pablo Bay (west of Carquinez Strait), Central Bay and South Bay (Cohen 2000). Tomales Bay, a moderately sized estuary, is within the boundaries of the sanctuary and includes the small tributary estuaries of Lagunitas and Walker Creeks. Other smaller estuaries occur along the open coast, including Estero Americano, Estero de San Antonio, Abbott's Lagoon, Drakes Estero, Limantour Estero, Bolinas Lagoon and Pescadero Marsh. Abbotts Lagoon, Drakes and Limantour Esteros, San Francisco Bay and Pescadero Marsh are not within the boundaries of the sanctuary, but they do influence conditions of the sanctuary. Bays and estuaries provide a variety of different habitats, including shallow regions such as flats, brackish water, eelgrass beds, salt marshes and tidal creeks. Lagoons and estuaries are among the most productive natural systems, due to the availability of protected, shallow, warm water, abundant light and high nutrient input. Anthropogenic stressors to the estuaries include habitat loss through fill, sedimentation from upland sources, the building of piers, docks and marinas, agricultural waste runoff, leaking septic tanks in the watersheds, vessel abandonment and introduced invasive species.

Rocky intertidal marine life communities are found between the high and low tide water levels and are exposed to a wide range of conditions. These rocky shores comprise 22% of the sanctuary shoreline. Distribution of organisms is strongly influenced by the amount of tidal inundation and wave exposure, which control the degree of exposure to air and the intensity of disturbance. Rocky headlands and the exposed coast are subjected to high wave action, and organisms there must be capable of surviving extreme conditions. Wave shock is reduced in areas that are protected by offshore rocks, reefs or islands. Organisms in rocky intertidal habitats are also exposed to drying and heating or cooling during low tide.

The Farallon Islands are located near the edge of the continental shelf within the California Current (see Figure 4). The high marine productivity of this region attracts a diverse assemblage of invertebrates, fish, seabirds and marine mammals. The Farallon Islands are the most important area for nesting seabirds within the contiguous United States, with over 300,000 adult birds nesting on the islands in May through July, during the height of the breeding season (GFNMS 2008b).

Offshore ocean environments include pelagic communities, benthic communities on the continental shelf and slope, and submarine canyon habitats. The vast majority of the sanctuary consists of open ocean habitats (pelagic habitats) that support a diverse and complex food web of plankton, invertebrates, fishes, sea turtles, birds and mammals. Pelagic habitats include newly upwelled waters, warmer waters in retention zones (e.g., Drakes Bay), plume influenced waters (immediately offshore of the Golden Gate) and surf zone waters. Benthic habitats consist primarily of soft bottom with small rocky outcroppings and areas of locally high relief. Shelf communities are subjected to shifting sediments due to wave action and subsurface currents. Organisms living on the slope must be extremely specialized for deepwater life in darkness, high hydrostatic pressure, and zones of low oxygen. The head of Pioneer Canyon, a small submarine canyon that cuts into the shelf of the Farallon Escarpment about 25 miles offshore from Half Moon Bay, supports deep-sea communities relatively close to shore. Canyon walls are often steep and rocky, with complex physical structures that provide shelter for various species. Canyon bottoms tend to slope gently and accumulate finer sediments such as silt and mud, providing habitat for species such as flatfishes (Noble and Kinoshita 1992, Airamé et al. 2003).

Living Resources

The sanctuary meets the land in the rocky intertidal zone. High-energy waves are often present along shoreline areas of the Gulf of the Farallones. (Photo: J. Roletto, GFNMS)
Figure 9. The sanctuary meets the land in the rocky intertidal zone. High-energy waves are often present along shoreline areas of the Gulf of the Farallones. (Photo: J. Roletto, GFNMS)
The Gulf of the Farallones is a complex region with high biological diversity. It is a nationally significant wildlife breeding and foraging area, home to 27 endangered or threatened species. The high diversity and abundance of birds, fish, marine mammals, invertebrates, algae and plants are due in part to the variety of island, coastal and subtidal habitats, and the highly variable physical processes affecting the area (e.g., localized upwelling).

Figure 10. Schools of rockfish congregate in forests of nearshore kelp. (Photo: T. Chess, NMFS)
Figure 10. Schools of rockfish congregate in forests of nearshore kelp. (Photo: T. Chess, NMFS)
Intertidal mudflats along the coast support high concentrations of burrowing organisms (clams, snails, worms and crabs) that are a main food source for shorebirds and wading birds. Invertebrates, birds (including the slowly recovering Brant Goose), Pacific herring and the juvenile stages of many coastal fish, depend on eelgrass beds in the estuaries to spawn and feed. In their journey from the ocean through bays and estuaries (e.g., Lagunitas Creek in Tomales Bay, Redwood Creek, Pescadero Marsh), the federally listed, threatened coho salmon depend on clear, cool water, riparian vegetative cover and drowned logs, and specific gravel size to complete their reproductive process.

Figure 11. In the open waters of the sanctuary, kelp rafts form an important floating habitat for congregations of fish, pinnipeds and birds. (Photo: P. Pyle)
Figure 11. In the open waters of the sanctuary, kelp rafts form an important floating habitat for congregations of fish, pinnipeds and birds. (Photo: P. Pyle)
Different invertebrate species are found along the exposed rocky coasts of the sanctuary in places like the Farallon Islands, Duxbury Reef and Fitzgerald Marine Reserve. These include the coralline algae that dominates the Farallon Islands rocky intertidal communities (Capitolo 2009), providing cover and food for a diverse population of marine invertebrates (Figure 9). Nearshore kelp beds, an important haven for congregations of fish, pinnipeds and birds, occur near Bodega Head, Point Reyes, Duxbury Reef, Point Bonita, Point San Pedro, Fitzgerald Marine Reserve, Pescadero and Pigeon Point (Figures 10 and 11).

Information is limited regarding the deeper, subtidal habitats of the sanctuary. At depths of about 60 feet, the lack of adequate light penetration limits kelp growth. Many organisms that live on the continental slope and in the deep sea depend on primary production occurring in surface waters, and produce their own light through bioluminescence, which is used to find or attract potential food or mates.

Invertebrates
Invertebrates can be found in most habitat types, from rocky shores and mudflats to deep benthic and pelagic habitats throughout the sanctuary. The intertidal community contains a diverse array of invertebrates including barnacles, limpets, black turban snails, mussels, sea anemones and sea urchins. At depths of about 60 feet (20 meters), encrusting coralline algae, brittle stars and serpulid worms are dominant among the life forms found. The invertebrate infaunal and epifaunal communities along the continental slope vary with depth and depend on specialized adaptations for life in the dark and under pressure. Numerous organisms can be found along the slope, including polychaete worms, pelecypod and scaphopod mollusks, shrimp and brittle stars.

Figure 12. A fully opened green anemone, Anthopleura sola, in a tidepool in Mussel Flat on Southeast Farallon Island. (Photo: J. Roletto, GFNMS)
Figure 12. A fully opened green anemone, Anthopleura sola, in a tidepool in Mussel Flat on Southeast Farallon Island. (Photo: J. Roletto, GFNMS)
Because of extreme conditions (low light, cold temperatures and high pressure), organisms found in the deep-sea environment eat less frequently and grow more slowly than species in surface waters (Airamé et al. 2003). The deep-sea pelagic invertebrate fauna of the sanctuary is dominated by the following phyla: Cnidaria, including hydroids (Hydrozoa), jellies (Scyphozoa), and sea anemones (Figure 12) and corals (Anthozoa); Ctenophora, including ctenophores (Nuda); Nemertea, including ribbon worms (Enopla); Chaetognatha, including arrow worms (Archisagittoidea); Annelida, including marine worms (Polychaeta); Mollusca, including chitons (Polyplacophora), snails and nudibranchs (Gastropoda), clams (Bivalvia), and squids (Figure 13) and octopuses (Cephalopoda); and Arthropoda, including barnacles and copepods (Maxillopoda), and isopods, amphipods, shrimp and crabs (Malacostraca). Little information is available regarding the species, status, or trends of deep-sea corals and sponges within the sanctuary.

Figure 13. Immature squid abound in plankton tows collected during spring SEA Surveys if the Gulf of the Farallones sanctuary. (Photo: J. Hall, GFNMS)
Figure 13. Immature squid abound in plankton tows collected during spring SEA Surveys if the Gulf of the Farallones sanctuary. (Photo: J. Hall, GFNMS)
Krill are keystone invertebrate species in the Gulf of the Farallones region, with Thysanoessa spinifera and Euphausia pacifica being the most common krill species found within the sanctuary. The California Current and localized upwelling zones provide conditions conducive for E. pacifica (the more oceanic species) to move onto to the continental shelf, where they become abundant and available to predators during late winter and spring. As the upwelling relaxes into the summer, E. pacifica moves offshore, where it is less available to predators, and T. spinifera (the more coastal species) becomes the dominant krill in shelf waters and predator diets (Edgar 1997, Sydeman et al. 2001, Abraham 2007, Elliott et al. 2009).

Fish
The sanctuary's diverse habitats contribute to a region of high productivity, and fish are an abundant resource. While bays and estuaries are important as feeding, spawning, and nursery areas, the continental shelf and slope are highly productive areas for commercial fisheries. The comparatively wide continental shelf and configuration of the coastline is vital to the health and existence of salmon (chinook and coho), northern anchovy, rockfish and flatfish populations. The extension of Point Reyes and the resulting current patterns tend to retain larval and juvenile forms of these and other species within the sanctuary, thereby easing recruitment pressures and helping to ensure continuing populations. The composition of fish species in the pelagic zone varies throughout the year with migration and spawning, and sanctuary waters surrounding the Farallon Islands (26 miles from the mainland) serve as an offshore location for shallow and intertidal fishes that further enhance finfish populations.

Juvenile planktivores or low-level carnivores of infaunal invertebrates are the most abundant estuarine fish in sanctuary waters (Yoklavich et al. 1991). Also common within the bays and estuaries that are within and adjacent to the sanctuary are Pacific herring (Clupea pallasii), smelt, starry flounder (Platichthys stellatus), surfperch, sharks and rays. Fish assemblages exhibit higher abundance and species richness during the summer with the invasion of young-of-the-year marine species (Allen and Horn 1975, Hoff and Ibara 1977, Allen 1982, Onuf and Quammen 1983, Yoklavich et al. 1991). There are a specialized group of fish adapted for life in tide pools found in the rocky intertidal zone, including monkeyface pricklebacks (Cebidichthys violaceus), rock eels (Pholis gunnellus), dwarf surfperch (Micrometrus minimus), sculpins including juvenile cabezon (Scorpaenichthys marmoratus), and blennies. Many of these species are important food sources for shorebirds and seabirds.

Rockfish, cabezon and small surfperches are commonly found in the rocky habitats of the continental shelf. Some of the common species include schools of black rockfish (Sebastes melanops) that frequently occur 10 to 20 feet above shallow rocky reefs. Shortbelly rockfish (S. jordani) are found in greatest abundances near the Farallon Islands, adults found in peak abundance over the bottom at depths of 400 to 700 feet. Cabezon are found on hard bottoms in shallow water from intertidal pools to depths of 250 feet. Subtidal habitats support large populations of juvenile finfish (e.g., flatfish, rockfish, etc.) and cabezon are also common in these zones, in and around rocky reefs and kelp beds.

Large predatory finfish such as sharks, tunas and mackerel are found in nearshore pelagic areas. Northern anchovy (Engraulis mordax), Pacific mackerel (Scomber japonicas) and market squid are common in this region and can be commercially valuable. Pelagic fish resources generally parallel species living in the nearshore subtidal zone. At the mid-depth or meso-pelagic range over sand and mud bottoms, chilipepper rockfish (S. goodie), widow rockfish (S. entomelas) and Pacific hake (Merluccius productus) are common. Kelp beds substantially increase the useable habitat for pelagic and demersal species and offer protection to juvenile finfish. Large populations of rockfish - more than 48 species - inhabit rocky banks in sanctuary waters deeper than 180 feet. Sablefish and flatfish such as sole, sanddab and halibut are found on nearshore and offshore soft-bottom habitats. Concentrations of sardines, northern anchovies and Pacific herring are a critical food source for birds and marine mammals. A small number of migratory pelagic species dominate the fisheries of Central and Northern California, including northern anchovy, Pacific sardine (Sardinops sagax), Pacific hake and jack mackerel (Trachurus symmetricus). These pelagic species spawn in the Southern California Bight and migrate into waters off Central and Northern California. However, the composition of larval fish species off Central and Northern California varies with oceanographic conditions.

Productive commercial fisheries for deep-sea fish operate on the continental slope. The species targeted include deep-sea rockfishes such as blackgill rockfish (Sebastes melanostomus), thornyheads (Sebastolobus sp.), sablefish (Anoplopoma fimbria) and Dover sole (Microstomus pacificus). Many of these species occupy similar habitats and generally are caught together (Love et al. 2002).

Figure 14. A large white shark swimming nears the Farallon Islands. (Photo: S. Anderson)
Figure 14. A large white shark swimming nears the Farallon Islands. (Photo: S. Anderson)
White Sharks
The sanctuary is home to one of the largest known concentrations of adult and sub-adult white sharks (Carcharodon carcharias) in the world (Figure 14). White sharks are seasonal visitors to the Gulf of the Farallones region, arriving during the summer months to nearshore areas in the vicinity of large pinniped haul-out and breeding colonies between Año Nuevo, the Farallon islands, Tomales Point at the north end of the Point Reyes peninsula and Bodega Headlands in Marin and Sonoma Counties. From August through November, white sharks have been seen feeding in the area, most notably at the Farallon Islands (Long et al. 1996, Pyle et al. 2002, Weng et al. 2007). The sharks leave the sanctuary every winter and migrate to the central Pacific and Hawaii (Jorgensen et al. 2009). The sanctuary population of white sharks appears to be genetically isolated (Jorgensen et al. 2009), with the number of adults in the range of 175 to 299 individuals (Chapple et al. 2010). Little is known regarding where sanctuary white sharks breed and pup. Current research findings indicate a stable population (Weng et al. 2007). White sharks are a key species in the marine ecosystem and removal of this apex predator could have cascading tropic impacts on the population dynamics of their prey (e.g., California sea lions and elephant seals). The California Fish and Game Commission passed a bill in 1994 (made permanent in 1997) protecting white sharks from "take" in California and mandating a long-term assessment of the population (Heneman and Glazer 1996). The Monterey Bay and Gulf of the Farallones sanctuaries promulgated regulations in 2009 for additional white shark protection from human disturbance by attraction and approach.

Turtles
Sea turtles in the northeastern Pacific typically follow warmer waters found in the higher latitudes during the summer and fall months. There are three species of sea turtle that are rarely found within the sanctuary (green sea turtle, Chelonia mydas; Olive Ridley, Lepidochelys olivacea; and loggerhead sea turtle, Caretta caretta) and one species, the leatherback turtle (Dermochelys coriacea), that is observed there annually, but in very low numbers. While in the sanctuary, they forage on gelatinous species from the class Scyphozoa (e.g., jellyfish) (Benson et al. 2007). Each of these species is listed as endangered or threatened under the Endangered Species List. The odds of sea turtles occurring in the cooler, temperate waters of the sanctuary are low and are greatly influenced by the relaxation of upwelling winds from Point Reyes south to Monterey Bay during the summer and fall months. Leatherback turtles are the largest of the sea turtles, weighing up to 1,500 pounds. Sea turtles are primarily threatened by habitat loss at their nesting areas in Mexico, Central America, South America and Indonesia, where egg harvesting and entanglement in nets and trawls from commercial and artisan fisheries are also greatly impacting the survival of these species. Within the past four years (2005-2009), three leatherback turtles known to have been hit by boat and ship propellers have been found along the Gulf of the Farallones shoreline.

Figure 15. Steller sea lions are one of several threatened species in the Gulf of the Farallones. (Photo: B. Wilson, GFNMS)
Figure 15. Steller sea lions are one of several threatened species in the Gulf of the Farallones. (Photo: B. Wilson, GFNMS)
Marine Mammals
Thirty-six marine mammal species have been observed in the Gulf of the Farallones sanctuary: six species of pinnipeds (seals and sea lions), 28 species of cetaceans (whales, dolphins and porpoises) and two species of otter. The sanctuary serves as a nursery for harbor seals (Phoca vitulina), northern elephant seals (Mirounga angustirostris), harbor porpoises (Phocoena phocoena) and Pacific white-sided dolphins (Lagenorhynchus obliquidens). The sanctuary also serves as a breeding ground for 20 percent of California's harbor seals (estimated at 32,000 in 2005). It also contains one of the last populations in California of the threatened Steller sea lion (Eumetopias jubatus) (Figure 15). The sanctuary is a destination feeding ground for endangered blue whales (Balaenoptera musculus) and humpback whales (Megaptera novaeangliae) and is a major migration route for gray whales (Eschrichtius robustus). The Farallon Islands provide habitat for breeding populations of five species of pinnipeds, including the once-extirpated populations of northern fur seals and northern elephant seals.

Breeding colonies of northern elephant seals, harbor seals, California sea lions (Zalophus californianus), and Steller sea lions are found on the coast and at the Farallon and Año Nuevo islands. A small colony of about 90 northern fur seals have recently resumed breeding on the South Farallon Islands during the summer. For more than 170 years prior to 1996, fur seals had not been known to breed on the Farallon Islands. From November through June, thousands of female and immature fur seals migrate through the western edge of the sanctuary along the continental shelf. Depending largely on their fur for insulation, fur seals and sea otters would be the most sensitive of all marine mammals to an oil spill.

Steller sea lions appear year-round throughout the sanctuary. This threatened population has decreased dramatically in the southern part of its range, which includes the Farallon Islands. The population in the Gulf of the Farallones region has declined by 80 percent compared to population numbers from 50 years ago (Rowley 1929, Bonnot and Ripley 1948, Ainley et al. 1977).

The California sea lion is the most conspicuous and widely distributed pinniped in the sanctuary. It is found year-round in the Gulf of the Farallones, with the population increasing at about 8 to 12 percent each year (Carretta et al. 2007). The northern elephant seal is the largest pinniped species in the sanctuary, with a total breeding population of about 13,000. They are primarily found at Point Reyes, the South Farallon Islands, Point Año Nuevo and Año Nuevo Island.

Figure 16. Pacific white-sided dolphins can often be seen by the thousands in sanctuary waters. (Photo: NOAA NMFS Southwest Fisheries Science Center)
Figure 16. Pacific white-sided dolphins can often be seen by the thousands in sanctuary waters. (Photo: NOAA NMFS Southwest Fisheries Science Center)
Twelve cetacean species are seen regularly in the sanctuary, and of these, the minke whale (Balaenoptera acutorostrata), harbor porpoise (Phocoena phocoena), Dall's porpoise (Phocoenoides dalli) and Pacific white-sided dolphin (Lagenorhynchus obliquidens) (Figure 16) are considered year-round residents. The harbor porpoise is the most abundant small cetacean in the Gulf of the Farallones, with 16,000 residing throughout Northern and Central California.

Gray whales migrate from Alaska southward through the sanctuary from December through February. Their northward migration through the sanctuary begins at the end of February and peaks in March. A few gray whales remain in the sanctuary year round. The gray whale population has recovered to the point that it was recently removed from the Endangered Species List. Other large baleen and toothed whales migrate to the sanctuary to feed in its nutrient-rich waters during the summer and fall months. The numbers of humpback and blue whales (estimated at 1,400 and 1,700 individuals, respectively, for California, Oregon and Washington waters) that feed in the sanctuary between April and November represent one of the largest concentrations of these whales in the Northern Hemisphere. They also represent two of the few recovering populations of baleen whales found throughout the world.

Seabirds
One of the most spectacular components of the sanctuary's abundant and diverse marine life is the large number nesting and migratory seabirds, comprising more than 500,000 birds of many different species. These birds are highly dependent on the sanctuary's productive waters. At least 19 marine and coastal bird species that are federally listed as threatened, endangered or species of concern can be found here, including the Marbled Murrelet (Brachyramphus marmoratus) and the Western Snowy Plover (Charadrius alexandrines). The sanctuary is also home to aquatic birds such as waterfowl, shorebirds like Black Oystercatchers (Haematopus bachmani), pelicans, loons and grebes. More than 160 species use the sanctuary for shelter, food or as a migration corridor. Of these, 57 species are known to use the sanctuary during their breeding season.

Figure 17. Common Murres in their chaotic rookery preparing for mating. (Photo: A. Schmidt, PRBO Conservation Science)
Figure 17. Common Murres in their chaotic rookery preparing for mating. (Photo: A. Schmidt, PRBO Conservation Science)
The Farallon Islands are home to the largest concentration of breeding seabirds in the contiguous United States. Eleven of the 16 species of seabird known to breed along the U.S. Pacific Coast have breeding colonies on the Farallon Islands and feed in the sanctuary. These include Ashy and Leach's Storm-Petrels (Oceanodroma homochroa, O. leucorhoa); Brandt's, Pelagic and Double-crested Cormorants (Phalacrocorax penicillatus, P. kenyoni, P. auritus); Western Gulls (Larus occidentalis); Common Murres (Uria aalge) (Figure 17); Pigeon Guillemots (Cepphus Columba); Cassin's Auklets (Ptychoramphus aleuticus); Tufted Puffins (Fratercula cirrhata); and Rhinoceros Auklets (Cerorhinca monocerata).

Shorebirds
The sanctuary includes crucial habitat for numerous shorebird species. Approximately 80 of the more than 400 shorebird species are found within sanctuary boundaries, 27 of which are regularly seen, such as the Black Oystercatcher, two species of dowitcher and several species of sandpiper. Generally, these birds probe about the shores, feeding on buried clams, worms, crustaceans and small fishes. A notable "prober," the Long-billed Curlew (Numenius americanus), has the longest beak (up to 23 centimeters, or nine inches) of any shorebird in the world. Easily recognizable shorebirds also include the Willet (Tringa semipalmata), Sanderling (Calidris alba), and Marbled Godwit (Limosa fedoa). Shorebirds can be seen at Bodega Bay, Esteros Americano and de San Antonio, Tomales Bay and Bolinas Lagoon, as well as many areas along the shore, such as Doran, Bolinas and Stinson beaches.

Other Coastal and Aquatic Birds
Herons, ducks and rails are seen in the sanctuary region. The Black Rail (Laterallus jamaicensis), listed as threatened on California's endangered species list, can be found in Tomales Bay and Bolinas Lagoon. Faced with rapidly diminishing habitat, rails are now rarely seen in the salt marshes of bay and coastal communities. At least seven species of heron, egret and bittern live in the sanctuary and adjacent wetlands. These long-necked wading birds are found in wetlands and along the shoreline.

More than 20 species of waterfowl inhabit the Gulf of the Farallones and surrounding waters, with many of them present year-round. Canada Goose (Branta canadensis), Surf Scoter (Melanitta perspicillata), Red-breasted Merganser (Mergus serrator) and Northern Pintail (Anas acuta) are examples of seasonal visitors to the area. Diversity is quite strong in these waterfowl, with species displaying great variation in color, size, shape and feeding behavior.

Maritime Archaeological Resources

The area encompassed by Gulf of the Farallones National Marine Sanctuary is rich in cultural and historical resources, and has a long and interesting maritime history. The seafloor preserves remnants of the sites where people lived and the vessels they used to conduct trade and combat. Ships, boats, wharves, lighthouses, lifesaving stations, whaling stations, prehistoric sites and a myriad of other heritage treasures lie covered by water, sand and time.

The history of California's central coast is predominantly a maritime one. From the days of the early Miwok inhabitants, throughout the exploration and settlement of California and up to the present day, coastal waterways have been a main route of travel, subsistence and supply. Ocean-based commerce and industries (e.g., fisheries, shipping, military, recreation, tourism, extractive industries, exploration and research) are an important part of the maritime history, modern economy and social character of this region. These constantly changing human uses define the maritime heritage of the sanctuary and help us to interpret our evolving relationship with maritime archaeological resources. Ports such as San Francisco, and smaller coastal harbor towns, developed through fishing, shipping and economic exchange. Today many of these have become major urban areas, bringing millions of people in proximity to the national marine sanctuaries of Central California. Many of these people are connected to the sanctuaries through commercial and recreational activities such as surfing, boating and diving.

Historical research suggests that nearly 180 vessel and aircraft losses occurred between 1595 and 1957 in the waters of what is now the sanctuary. The sanctuary has collaborated with state and federal agencies and the private sector to gather resource documentation and to create opportunities to locate and record submerged archaeological resources. Some of these archaeological resources have been located and inventoried by the National Park Service (NPS). Existing databases, a review of primary and secondary resource documentation, and two reports by the NPS published in 1984 and 1989 provided the framework for the sanctuary to create a shipwreck inventory and site assessment (Murphy 1984, Delgado and Haller 1989). The Minerals Management Service and the California State Lands Commission shipwreck databases have also contributed to the overall resource inventory. Research continues today by NOAA and NPS to expand the inventory and make recommendations for future survey opportunities.

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1 Turning a ship hull to remove marine growth.

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