Pressures on the Sanctuary
Numerous human activities and natural events and processes affect the condition of natural and archaeological resources in marine sanctuaries. This section describes the nature and extent of the most prominent human induced pressures in the Gulf of the Farallones National Marine Sanctuary.
Impacts from vessels, including oil pollution, disturbances to certain living resources, sunken vessels, ship strikes of wildlife, and dredged material resulting from maintenance of shipping channels, are a significant threat to the protection and health of the sanctuary. Three major shipping lanes converge in the sanctuary just west of the Golden Gate Bridge at the entrance to San Francisco Bay (Figure 18). The volume of traffic in and out of San Francisco Bay is large. In 2008, nearly 4,000 tank and non-tank vessels made this transit (see Table 3, Water Quality Question 4 in Coastal/Offshore section). Approximately half of these vessels transit south off the coast of California, while the other half transit north or west of San Francisco (HSCSFBR 2008) (Figure 19).
Crude oil production in California averaged 731,150 barrels per day in 2004, ranking the state fourth in the nation among oil-producing states (Sheridan 2006). California is also a major refining center for West Coast petroleum markets, with a combined crude oil distillation capacity totaling more than 1.9 million barrels per day - third highest in the nation. California's oil production and distillation activities, and status as the nation's greatest gasoline consumer, provide a high level of risk from oil tankers moving up and down the coast.
Historically, the total number of spills from transiting vessels is small, but the potential impacts may be enormous given the number and volume of vessels, and their proximity to the Farallon Islands and major seabird and marine mammal populations (Table 1). In 2007, in a report from the Harbor Safety Committee, the U.S. Coast Guard documented 868 tank vessels and 2,787 deep-draft non-tank vessels that transited San Francisco Bay. Large commercial vessels are of particular concern for spills, since they can carry up to one million gallons of bunker fuel, a heavy, viscous fuel similar to crude oil. Examples of two oil spills that impacted sanctuary resources include the S/S Jacob Luckenbach in 1953 and the T/V Puerto Rican in 1984.
Major and moderate oil spills causing significant oil pollution in the Gulf of the Farallones, since designation in 1981. (Source: Carter and Golightly 2003 and Hampton et al. 2003a)
|Vessel||Year||Estimate of Spills|
|S/S Jacob Luckenbach||sank 1953||No known estimate is available for amount that initially leaked after colliding with another ship; chronic leaks are estimated to be more than 300,000 gallons from 1953-2002.|
|T/V Puerto Rican||1984||Release of at least 5.4 million liters of oil (365,500 gallons of bunker fuel); leaked for several years after an explosion.|
|T/B Apex Houston||1986||Release of an estimated 97,600 liters of crude oil after an accident while under tow.|
|S/S Cape Mohican-SF Drydock||1996||Release of an estimated 151,500 liters of heavy bunker fuel oil.|
|T/V Command||1998||Release of an estimated 3,000 gallons of intermediate bunker fuel while in transit.|
|S/S S Jacob Luckenbach --related pollution episodes||1989-2002||Greater than 85,000 liters of bunker fuel oil leaked sporadically for several years and during the clean-up process.|
|S/S Cosco Busan||Nov. 2007||An estimate of the amount of oil spilled and subsequent impacts from the S/SCosco Busan strike are in the process of being evaluated (therefore, this event is not part of this assessment).|
T/V Puerto Rican
In November 1984, the tanker vessel (T/V) Puerto Rican exploded in the Gulf of the Farallones and eventually released about 5.4 million gallons of oil into the Gulf of the Farallones sanctuary over a two-week period (Figure 20). The back half of the tanker eventually sank with 365,500 gallons of bunker fuel that leaked for several years (Hampton et al. 2003a).
The long-term impact of the bunker fuel in the sunken stern is unknown. However, it was estimated by the state and federal trustee agencies that 26 bird species were directly affected by the incident, killing at least 2,874 individual birds (Ford et al. 1987). Also affected were elephant seals, northern fur seals, shrimp, krill, crabs and rockfish.
S/S Jacob Luckenbach
In 1953, a 468-foot freighter, the S/S Jacob Luckenbach, left San Francisco bound for Korea (Figure 21). It collided with another ship and sank in 180 feet of water. The wreck came to rest 17 miles west-southwest of San Francisco and contained 457,000 gallons of bunker fuel (Hampton et al. 2003b). The sunken ship leaked oil sporadically for many years, but was not initially linked to a major wildlife disaster.
However, in 2002, researchers investigating a large concentration of tarballs and oiled seabirds at Point Reyes and along the San Mateo County coast determined that the chemical signature of oiled feathers matched the oil in the S/SJacob Luckenbach. It was estimated that from August 1990 through December 2003, 51,000 birds and eight sea otters were oiled and killed. Of these, approximately 85 percent of the deaths are attributed to the oil leaking from the S/S Jacob Luckenbach. More than 50 species of birds were impacted; with the greatest numbers being Common Murres, Red Phalaropes, Northern Fulmars, Rhinoceros Auklets, Cassin's Auklets and Western Grebes. Four federally and state-listed species, the Brown Pelican, Western Snowy Plover, Marbled Murrelet and California sea otter, were impacted as well. Ashy Storm-Petrels were also impacted in significant numbers, relative to their population size (Hampton et al. 2003b).
In addition to the threat of oil spills, many vessels, some dating as far back as the 17th century, litter the sea floor of the sanctuary. Among these are the many vessels deliberately sunk between 1951 and 1987. Included in the inventory of sunken vessels is the highly radioactive World War II aircraft carrier USSIndependence, which was exposed to atomic tests and sunk by the U.S. Navy in 1951 at an unspecified location off the California coast, possibly in the Gulf of the Farallones.
Hundreds of millions of tons of waste have been dumped into the Gulf of the Farallones since the mid-1800s (Chin and Ota 2001). Since the 1940s, this has included waste from oil refineries and fruit canneries, acids from steel production, and ships from World War II and other unwanted vessels. From 1958 to 1969, the U.S. military disposed of chemical and conventional munitions at several sites in the Gulf of the Farallones, mostly by scuttling World War II-era cargo vessels (Chin and Ota 2001).
Plastic waste also threatens sanctuary resources. Sources of plastic waste are both land and ocean-based. Land-based sources of marine debris include: litter washed into the bay through storm drains and outflow from combined sewer treatment systems; garbage from landfills; shoreline recreational activities; improper handling of garbage in transport and on-site storage; and plastic resin pellets discharged from plastics manufacturing facilities into storm drains and nearby waterways (Gordon 2006, International Pellet Watch Web site). Ocean-based sources generally include lost fishing gear and dumping of garbage at sea by vessels and oil platforms (UNEP 1995, NOAA Office of Public and Constituent Affairs 1999).
- Marine debris and entanglement
- Trends in human-recreational use, dogs and shorebird interactions
- Species abundance and geographic trends
- Species inventories and distribution for national and state parks
- Predator-prey abundance and geographic trends for Snowy Plovers and Common Raven
- Species inventories for specific beaches and larger regional trends
- Oil spill response and restoration efficacy
Plastic waste is a worldwide problem. There are many potential sources of plastic debris, and it can remain in the marine environment for a very long time before fully degrading. Plastic particles may be ingested by both marine organisms that select food by sight and filter feeders that do not. Plastic waste has also been shown to entangle marine wildlife in the Gulf of the Farallones and elsewhere. From 2001 to 2005, the cause of death for 0.7 percent (n = 8,475) of the bird carcasses documented during sanctuary Beach Watchsurveys was entanglement in marine debris (Moore et al. 2009) (Figure 22). Based on Beach Watch surveys of dead seabirds, an estimated 200 birds are killed every year in the Gulf of the Farallones due to entanglement in fishing gear and other plastic debris. Small plastic fragments and pellets in the ocean and inland waterways have been found to adsorb pollutants from the marine environment - most notably, persistent organic pollutants (Karapanagioti and Klontza 2007). When marine life mistake these pellets for food, they are likely to ingest a wide array of contaminants, posing the threat of PCB accumulation and the increased likelihood of starvation (Ryan et al. 1988). Another negative consequence of plastic fragments in the marine environment is that they have been found to attract marine organisms such as bacteria, diatoms, algae, barnacles, hydroids, tunicates and bryozoans that attach to and "raft" on them, which can contribute to the spread of invasive species.
San Francisco Bay's 85 miles of navigable waterways require annual maintenance dredging (Chin and Ota 2001). Oil tankers and container vessels require 40 to 60 feet of water for safe transit. Channel dredging is necessary to prevent deep-draft vessels from running aground or rupturing their hulls, which could cause millions of dollars in environmental damage to the bay's fragile habitats. Environmental concerns and limited disposal capacity for dredged material in the Bay have made it necessary to find a suitable dumping site. As such, the San Francisco Deep Ocean Disposal Site (SF-DODS) was designated and is located 55 miles beyond the Golden Gate Bridge and outside of the Gulf of the Farallones sanctuary's western boundary (Figure 23) (Chin and Ota 2001).The ocean disposal site off San Francisco is the farthest offshore and in the deepest water of any ocean disposal site in the United States. The dredged sediment is clean, containing no toxic levels of chemicals (LTMS 1998). However, dumping even clean sediment creates environmental concerns. First, it can change the character of the seafloor habitat and directly smother bottom dwelling organisms. Second, it can affect water clarity. The high productivity of the Gulf of the Farallones is based on phytoplankton blooms that require light. Discharging sediment blocks sunlight, restricts the growth of plankton and disrupts the feeding of fish, birds and marine mammals. While the dump site is located outside the boundaries of the sanctuary, currents could possibly carry sediment particles into the sanctuary, so additional monitoring within the sanctuary remains prudent.
Between 1946 and 1970, approximately 47,800 containers of low-level radioactive waste were dumped into the Gulf south and west of the Farallon Islands (Chin and Ota 2001). The 55-gallon drums litter a 540-square-mile area of seafloor, much of it in the Gulf of the Farallones sanctuary at depths ranging from 300 to more than 6,000 feet (Figures 23 and 24). The containers were to be dumped at three sites designated by the Navy, but many were not dropped on target, probably due to inclement weather and navigational uncertainties. Therefore, assessing any potential environmental hazard from radiation or contamination has been difficult (Karl 2001). In addition, evidence suggests that several other types of wastes were dumped, including cyanides, mercury, beryllium and other heavy metals, dredge spoils, explosives, and garbage, although available documentation does not specify an origin (Jones et al. 2001b).
Questions also exist on the condition of the barrels and whether or not it is more beneficial for the health of the sanctuary to leave the containers on the seabed or attempt to remove them. Personnel changes in all involved agencies have led to institutional knowledge loss. Additionally, questions regarding agency role and responsibility need to be addressed (Chin and Ota 2001, Karl 2001).
San Francisco Bay, adjacent to the Gulf of the Farallones sanctuary, is considered the most invaded aquatic ecosystem in the world (Cohen and Carlton 1998), with more than 255 introduced species. The Bay's close proximity to the sanctuary elevates the risk of new introductions to Gulf of the Farallones estuaries. Indications are that introduced species are a great threat to rare, threatened or endangered species in the U.S., second only to habitat destruction (Brynes et al. 2007). In general, introduced species in the marine and estuarine environment alter species composition, threaten the abundance and diversity of native marine species, interfere with the ecosystem's function and disrupt commercial and recreational activities (GFNMS 2008a). Of the highest concern to sanctuary management are the following species: wakame (Undaria pinnatifida), green crab (Carcinus maenas), Japanese false cerith, or mudsnail (Batillaria attramentaria), and Atlantic smooth cordgrass (Spartina alterniflora) and its hybrids with the native cordgrass Spartina foliosa (Byrnes et al. 2007).
Nearshore discharge of ballast water from large vessels is a common source of introduced species. Most organisms carried in ballast water are in the larval stage of their life cycle, and estuaries and harbors can provide optimal environments for the growth of some of these organisms. Viruses, bacteria and other pathogens have also been identified in ballast water. The discharge of ballast water into California waters or a marine sanctuary from a vessel with sufficient holding tank capacity is prohibited.
Introduced species may also be transported on commercial and recreational vessel hulls, rudders, propellers, intake screens, ballast pumps and sea chests. Other vectors for the spreading of introduced species include recreational and research equipment, debris, dredging and drilling equipment, dry docks, and buoys. Organisms transported or used for research, restoration, educational activities, aquarium activities, live bait, aquaculture, biological control, live seafood, and rehabilitated and released organisms also have the potential for accidental or intentional release into marine and estuarine environments. Of additional concern are genetically modified species that either escape or are released into the ocean (Cohen 1997, Cohen and Carlton 1998, GFNMS 2008b).
A variety of recreational (Figure 25) and commercial fishing activities occur in the sanctuary. Salmon, California halibut, albacore, rockfish, lingcod, sanddabs, surfperch, striped bass and Dungeness crab are the primary target species for sport fishing in the Gulf of the Farallones sanctuary. Northern anchovy and Pacific sardine are also targeted for bait. On weekend days with low tides, especially during summer vacation months, clam diggers harvest gaper clams, geoducks, littlenecks, basket cockles and Washington clams (T. Moore, CDFG, pers. comm.). Some intertidal organisms are harvested for sustenance or by small commercial operations. These organisms include barnacles, limpets, black turban snails, mussels, abalone and sea urchins. The most important commercial harvests include Pacific herring, salmon, rockfish, halibut and other flatfishes, and Dungeness crab. Most of the commercial catches harvested in Gulf of the Farallones sanctuary are landed in Bodega Bay, Bolinas, San Francisco, Oakland, Sausalito and Half Moon Bay (Scholz et al. 2004).
Gear types used in the sanctuary include diving equipment, hook-and-line, set and vertical long lines, troll, gillnets, seines, mid-water and bottom trawls, various traps, and miscellaneous gear such as cast net, hoop net, pelagic trawl, spear fishing, dredging and fish pumps (Scholz et al. 2004). Hook-and-line and long lines are generally used to catch rockfish, flatfish and lingcod. Gillnets are used in Tomales Bay to catch Pacific herring. Seines are primarily used for market squid harvesting, which has traditionally taken place in the area, although squid is currently not a major target species (Leet et al. 2001). Typical market squid fishing gear includes high-wattage squid attraction lights, which have been restricted in sanctuary waters by the state because of the potential to cause disturbance to and increased predation of nocturnal seabirds. Since 2005, California has prohibited bottom trawling within three miles of shore, and the National Marine Fisheries Service has designated several areas within the sanctuary as Essential Fish Habitat, where no trawling is allowed (see Figure 34, Habitat Question 5 in Coastal/Offshore section). Although bottom trawling activities have decreased markedly in the sanctuary in recent years, this activity still occurs within sanctuary waters. Traps are primarily used to catch Dungeness crab. There is currently no limit on the number of traps that can be set in sanctuary waters. It is estimated that approximately 50,000 to 100,000 traps are set each year within the sanctuary. According to surveys of fishermen, approximately 10 percent of all set traps are not recovered, resulting in a substantial amount of debris in the form of derelict trap gear (traps and lines) within sanctuary waters (Z. Grader, Pacific Coast Federation of Fisherman's Associations, pers. comm.).
Nonpoint Source Pollution
Coastal and Offshore Environments
Open coastal and offshore areas of the sanctuary are also threatened by nonpoint source pollution. However, the threat is generally considered to be less for open-water areas than for estuaries because they are somewhat protected by their distance from the sources of pollutants and land-based runoff and by more active circulation and mixing that dilutes pollutants with offshore waters. Nevertheless, the coastal and offshore regions of the sanctuary are threatened by acute events (large ship-based spills) and ongoing chronic sources (San Francisco outflow). In addition to current threats, persistent organic pollutants such as DDT and PCBs were widely used nationwide before the mid-1970s and residuals of these chemicals still remain in sediments and organisms within the sanctuary. Elevated levels of pollutants have been reported for fish, seabirds and marine mammals, and are suspected to have caused and sustained in part the decline of pupping rates in Steller sea lions (Sydeman and Jarman 1998).
When precipitation falls over the land, it follows various routes. Some of it evaporates, returning to the atmosphere, some seeps into the ground, and the remainder becomes surface water, traveling to oceans and lakes by way of rivers and estuaries. Impervious surfaces associated with urbanization and runoff alter the natural amount of water that takes its typical route into storm drains. The consequences of this change are a decrease in the volume of water that percolates into the ground, thus resulting in an increase in the volume and decrease in quality of surface water. These hydrological changes have significant implications for the quantity of fresh, clean water that is available for use by humans, fish and wildlife. Outflow from San Francisco Bay carries pollution from the 8 million people living in the Bay Area, including sewage outfalls, combined sewage overflows, agricultural waste products from the Central Valley, and residual sediments and metals from historical mining. The Bay has been identified by the California State Water Resources Control Board as being out of compliance with state water quality standards for several pesticides, metals, sedimentation, PCBs and exotic species (California State Waters Resources Control Board 303(d) list Web site). In addition, treated wastewater discharges from the city of San Francisco and San Mateo County are located to the southeast of the sanctuary.
Estuarine and Lagoon Environments
Threats to nearshore areas include aspects of livestock grazing, agricultural activities, derelict vessels (Figure 26), past mining activities, small marinas and boat work operations (often having highly contaminated sediments), and aging and undersized septic systems. Of special concern are the estuarine habitats of Estero Americano, Estero de San Antonio, Tomales Bay and Bolinas Lagoon, where circulation is more restricted than along the open coast and where organisms that rely on estuarine conditions are exposed to less diluted runoff, which may be polluted. Further, due to long residence time and weak flushing, the estuarine environments are threatened by small-scale accidental spills from vessels, land-based tanks or other sources, and small-scale discharges such as oily bilge water, detergents from deck wash, runoff from small boat works or sewage from boats, septic systems, leaking sewers, or agricultural runoff. Residual pollutants from past practices such as mining operations and diversion of fresh water have the greatest potential to impact more narrow and shallow waterways, such as creeks and the estuaries into which they flow.
Pressure on marine resources continues to grow as the human population increases around coastal areas and access to the offshore environment becomes easier. With the multitude of opportunities for harvesting, observing and interacting with nature comes the potential for wildlife disturbance (Figure 27).
Wildlife disturbance may be caused by direct and indirect factors. Disturbance is often caused by natural events such as storms, mud slides and cliff erosion, fluctuations in water temperature, and physical/chemical changes to water. It can also be the result of human activities, including observing and feeding wild animals, encroachment on breeding areas and rookeries, collecting tidepool inhabitants, light and noise from recreation and commercial activities, and trampling intertidal habitats (Figure 28).
Of specific concern to the Gulf of the Farallones sanctuary are negative impacts associated with: trampling and collecting in the intertidal; deliberate interactions with white sharks; disturbances from low-flying aircraft, boaters and hikers; noise transmitted through the water from seismic exploration, vessel and military activities; and shark, seabird, marine mammal and sea turtle entanglements and ingestion of fishing gear.