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 Monterey Bay National Marine Sanctuary.
The sanctuary is located in an area of critical importance to the conduct of maritime commerce, which is a major component of the regional and national economy. There are approximately 4,000 coastal transits of the sanctuary each year by large vessels. Approximately 20 percent of these transits are crude oil tankers. The majority of the remainder is large commercial vessels such as container ships and bulk product carriers. Vessel traffic within the sanctuary was a major issue of concern raised during the sanctuary designation process. Large commercial vessels were of particular concern for spills because they traveled closest to shore and can carry up to 1 million gallons of bunker fuel, a heavy, viscous fuel similar to crude oil, which they use to power themselves. The historical record of spills for the Pacific Coast indicates that the total number of spills from transiting vessels is relatively small in number, but the impacts could be enormous given the number and volume of these vessels and the potential size of a spill.
Lost cargo from container ships poses an additional pressure to sanctuary resources. The potential impact of lost containers on natural resources includes the crushing and smothering of benthic organisms, the introduction of foreign habitat structure and shifts in local ecology. There is likely to be an expanding benthic footprint over time as the containers degrade and collapse, spreading their contents along the ocean floor. There is potential for entrapment of marine organisms, ingestion of foreign objects, as well as deposition of plastics and other chemical pollutants.
Military use of the sanctuary includes air, surface and underwater activity. Some activity includes the use of non-explosive ordinance, sonar, smoke markers and the temporary placement of objects for torpedo firing or sonar location training. Air activities include aircraft carrier takeoffs and landings, and low-level air combat maneuvering. The U.S. Navy uses special zones for submarine operations and minesweeping training exercises. On occasion, U.S. Marines practice amphibious landings on sanctuary beaches. The military also conducts non-combat-related preparedness activities such as underwater cable repair and breakwater maintenance. Concerns regarding the military activity in the sanctuary are primarily related to conflicts and disturbances with marine life or benthic habitat, and disturbance of seabird roosting areas by aircraft. Concerns have also arisen regarding military proposals to use underwater acoustic devices that could interfere with marine mammal communications, behavior or health.
Commercial and Recreational Fishing
Commercial and recreational fishing are important components of the culture and economy of the sanctuary, with 560 commercial vessels making landings at the five main ports in and near the sanctuary (Bob Leos, CDFG, pers. comm.), along with substantial recreational fishing. Over 50,000 recreational anglers fished for rockfish and salmon from 50 party or charter boats in the area in 2007 while others fished from private boats and from shore. About 200 species are typically caught in the commercial and recreational fisheries, with the bulk of the commercial landings composed of sardine, anchovy, squid (Figure 17), sablefish, Dover and petrale sole, mackerel, and Dungeness crab (Starr et al. 2002). The five primary gear types used are purse seines, trawl nets, hook-and-line gear, pots and traps, and gill nets. Although many harvested stocks are at or above fisheries management targets, marine resource managers are concerned about the depressed levels of certain stocks, habitat threats from some fishing gears, bycatch of sensitive species, and potential community and ecosystem-level effects of fishing.
Pressures to Water Quality
RunoffWater quality is a key element that unites all sanctuary resources. The sanctuary is adjacent to 450 kilometers of California's coast, with 11 major watershed areas draining over 18,000 square kilometers, ranging from relatively pristine conditions to heavily agricultural and urbanized areas. The runoff from rainfall and irrigation water can pick up a variety of pollutants and carry them into storm drains, streams, rivers, wetlands, harbors, bays, and shorelines, which can impair the quality of these water bodies (Figure 18).
Urban runoff is a leading cause of water pollution. Urban areas contain up to 90 percent hard surfaces such as rooftops and pavement, where water collects and quickly runs off. Urban runoff is difficult to prevent because it is nonpoint pollution with sources such as yards, sidewalks, streets, construction sites, and parking lots. Deposits of contaminants (e.g., oil, grease, pesticides, herbicides, soil, pet droppings) in these areas are flushed by rainwater and other means down the storm drains and directly into a river or bay. The water flowing through storm drains is untreated and therefore carries pollutants into local waterways. Problems that result from pollution and alteration of flow pathways are exacerbated by population growth which drives further urbanization in watersheds. In addition, rain runoff volumes are increased in urban areas due to the increase in impervious surfaces, such as streets and parking lots. Under such conditions, the discharge rate can easily double or triple, causing increased chances for flooding. The pollution content of rainwater runoff is greatest during the first few hours of a storm as all standing deposits are washed away. This "first flush" can cause stress for aquatic organisms. High bacterial loads in urban runoff can also lead to beach closures, reducing recreational opportunities.
Runoff from agricultural land is another source of pollution. Potential problems include: elevated nutrient levels (e.g., nitrate, urea), sedimentation, pesticides (e.g., DDT and toxaphene), suspended solids, and bacterial and protozoan contamination. These contaminants can have a variety of biological impacts including algal blooms, toxicity, reproductive anomalies, reduced recruitment of anadromous species, morbidity and mortality to marine mammals, transfer of human pathogens, and interference with recreational uses of the sanctuary due to beach closures.
Pressures to Water Quality
Beach ClosuresSince the sanctuary designation in 1992, runoff and spills along the sanctuary's coastline have periodically resulted in high levels of coliform bacteria in coastal waters, resulting in hundreds of beach closures or warnings annually (Figure 19). Coliform bacteria are used as indicator organisms, and while they may not cause disease in humans, their presence tells us that water may be contaminated with organisms that do cause human health impacts such as fever, flu-like symptoms, ear infection, respiratory illness, gastroenteritis, cryptosporidiosis, and hepatitis. Sources of contaminated water include runoff from urban, suburban and rural areas, aging sewer infrastructure systems pressed to meet increasing demands, and contaminated flows from creeks and rivers. Contributing factors that generate these sources include illicit storm drain connections, improper disposal of materials which clog pipes and cause overflows, cracked or damaged pipes, overflow of sewer systems during storm events, septic system leaching, and various domestic and wildlife sources.
Harmful Algal BloomsA harmful algal bloom (HAB) can occur when certain types of microscopic algae grow quickly in water, forming visible patches that may harm the health of the environment, plants, or animals. HABs can deplete the oxygen and block the sunlight that other organisms need to live, and some HAB-causing algae release toxins that are dangerous to animals and humans. In Monterey Bay and other coastal waters in the sanctuary, populations of naturally occurring algae occasionally grow to very high concentrations and some can produce extremely potent biotoxins. These biotoxins can be transferred up the food chain, sometimes poisoning seabirds and marine mammals or closing the harvest of commercial species such as shellfish. However, not all blooms are toxic, and even species that can produce toxins do not always do so, making the timing and location of harmful algal blooms difficult to predict.
In the last decade one particular species, Pseudo-nitzschia australis, has received a great deal of attention in Monterey Bay. It blooms in Monterey Bay from late spring to early fall and can produce domoic acid, a potent neurotoxin that can cause neural damage, disorientation, short-term memory loss and even seizures and brain damage in vertebrates. Domoic acid is readily passed up the food chain. The toxin is consumed along with the phytoplankton by small fishes and zooplankton, which are in turn eaten by larger fishes, seabirds, and mammals. Domoic acid can become concentrated in filter feeding animals that are eaten by humans, such as mussels, and can cause serious illness and even death.
Marinas and BoatsWater pollution from activities associated with marinas and boating within the sanctuary is also a pressure on sanctuary resources. Boater-generated impacts on water quality generally fall into four categories: toxic metals primarily from anti-fouling paints, hydrocarbons from motor operations and maintenance procedures, solid waste and marine debris from overboard disposal, and bacteria and nutrients from boat sewage.
Cruise ShipsLarge cruise ships began visiting Monterey in 2002 (Figure 20). These ships provide local businesses with economic benefits, but both the public and businesses have raised concerns about environmental issues associated with these ships. Cruise ships are of enormous size, and are capable of generating massive volumes of waste. The main pollutants generated by a cruise ship are sewage (also referred to as black water), gray water, oily bilge water, hazardous wastes, and solid wastes. While large cruise vessels are the equivalent of small cities in regard to waste production, they are not subject to the strict environmental regulations and monitoring requirements imposed on land based facilities, such as obtaining discharge permits, meeting numerous permit conditions and monitoring discharges.
Oil or Chemical SpillsOil and chemical spills in the sanctuary could range from small, localized spills to large events that span hundreds of kilometers of coastline. Small spills tend to be associated with fuel and oil discharges due to vessel groundings, sinkings and plane crashes. A larger oil or chemical spill may result from offshore shipping traffic, sunken vessels or natural seeps. A large spill could have a major impact on foraging birds, marine mammals and fishes, as well as important habitat like kelp beds, wetlands and rocky shores, and on tourism and the coastal economy.
DesalinationThe demand for an already overtaxed fresh water supply continues to increase with the growing population of California's coastal communities, and more communities are exploring the feasibility of desalination plants to augment fresh water supplies. Three desalination facilities currently operate within the boundaries of the sanctuary (Figure 21); however there has recently been an increase in interest for both private and public desalination plants. Approximately ten facilities have recently been proposed. Desalination plants have the potential to negatively impact the marine environment through the introduction of brine waste effluent and other substances to sanctuary waters. Additionally, the construction of desalination facilities and associated pipelines often causes alteration of the seabed. Larval and adult forms of marine invertebrates and fishes can be sucked into intake pipes, thus potentially having detrimental impacts on sea life.
Dredging and Dredge DisposalPeriodic dredging of the local harbors is necessary to continue to allow access for vessels (Figure 22). There are four major harbors adjacent to the Monterey Bay sanctuary: Pillar Point, Santa Cruz, Moss Landing, and Monterey. Santa Cruz and Moss Landing regularly dredge the bottom of the harbor. The Monterey Harbor has dredged on a sporadic basis in recent years. Pillar Point Harbor has historically had little need for dredging, though that status may change in the future.
Dredging impacts seafloor communities both at the dredging site and at the disposal site. The physical disturbance of dredging damages or removes organisms living in or on the seafloor and can mobilize buried chemical contaminants. The disposal of dredge material can smother organisms and introduce chemical contaminants at the disposal location. In addition, dredging to deepen channels in harbors can alter water flow dynamics and future sediment deposition rates in the harbor and adjacent habitats.
Erosion and Coastal ArmoringAbout 86 percent of the California coast experiences active erosion due to natural and anthropogenic causes (Griggs 1999). Shoreline protective structures have been used in the sanctuary to protect infrastructure and other development from wave action, or to retain soil and avoid erosion (Figure 23). This practice is commonly known as coastal armoring. By 1998, coastal armoring had been installed to protect about ten percent of the coastline statewide (Griggs 2005). With increases in development, continued natural erosion of coastal bluffs, and projected sea level rise, additional requests will come to install structures both to access the coast and to protect private and public property from erosion. Poorly planned erosion control structures can cause even more erosion of adjacent beaches, possibly displacing sanctuary resources, and can lead to diminished beaches.
Landslide DisposalDeposition of material from landslides along the sanctuary's steep coastline can bury intertidal and subtidal habitat, and increase sand scour that inhibits larval settlement in certain habitats. Some of these slides occur naturally, while others are created or exacerbated by highway design, repair, and maintenance practices.
The rapid expansion of Internet technology has created a surge of proposals to install submerged fiber optic cables in the sanctuary. Installation of submerged cables in the sanctuary alters the seabed, causing environmental impacts and creating potential hazards for fishing activities. Monterey Bay National Marine Sanctuary regulations currently prohibit alterations of the seabed, yet allow, via permit or authorization, for some otherwise prohibited activities. Monterey Bay sanctuary regulations recognize certain activities that may benefit the sanctuary, such as education, research, or management; thus a cable that provides these benefits could be permitted under existing regulations. Cables that are for commercial purposes, such as telecommunications, are less preferred under existing regulations.
Second only to direct habitat loss, non-indigenous species (also called introduced or invasive species) are recognized world-wide as a major threat to ecosystem integrity. Non-indigenous species in the marine environment can alter species composition, threaten the abundance and/or diversity of native marine species, interfere with ecosystem function, and disrupt commercial and recreational activities. They can cause local extinction of native species either by preying on them directly or by out-competing them for food or space. Once established, non-indigenous species can be difficult to eradicate (Figure 24). Non-indigenous species also exacerbate biotic homogenization, the process of communities becoming more similar due to growing proportion of shared non-native species (Lockwood et al. 2007, Sax et al. 2005).
The most important pathway for the world-wide introduction of marine species is transportation via large vessel ballast tanks and hull-fouling, though other mechanisms, such as introduction through improper disposal of aquarium materials, bait and seafood packing materials, aquaculture operations, and research activities, also contribute to the problem. The main vectors that have introduced species into the sanctuary, and into Elkhorn Slough in particular, are small boat traffic and oyster culture (Wasson et al. 2005).
Terrestrial non-indigenous species can have negative impacts on living resources in the sanctuary. Nest predation by rodents that have been introduced to many offshore islands by human activities can have devastating impacts on nesting seabird colonies. Feces of the non-indigenous opossum and the domestic cat are the main sources of the parasites Sarcocystis neurona and Toxoplasma gondii, two of the most important infectious diseases affecting southern sea otters (Kreuder et al. 2003).
Motorized and Non-motorized VesselsThe use of motorized or non-motorized vessels (outboard or inboard boats, kayaks, canoes, underwater scooters, or other types of water craft) to interact with marine mammals in the wild is a rapidly growing activity nationwide. NOAA National Marine Fisheries Service and the Monterey Bay National Marine Sanctuary have received complaints from members of the public that describe operators of motor vessels driving through groups of dolphins in order to elicit bow-riding behavior, whale watching vessels getting too close to whales or chasing animals in order to get a better view of them, and kayakers utilizing the quiet nature of their vessels to approach too closely to sea otters and harbor seals. Fatal blunt trauma injuries to sea otters suggest that they are being hit by small boats, particularly in areas near Elkhorn Slough and harbors.
Overflight ImpactsLow flying aircraft are known to cause seabirds, shorebirds, pinnipeds, and whales to exhibit avoidance responses, such as rapid surface diving and flushing from roosts, nests and haul-outs. There are a variety of user groups associated with this activity, including commercial film making flight operations, private non-profit aviation, and military and agency aircraft. Potential impacts from low-flying aircraft are addressed by a specific prohibition on flying below 1,000 feet (300 meters) in designated overflight zones with sensitive wildlife. Some implementation problems have occurred due to pilot's lack of understanding and acknowledgement of the zones.
Commercial Harvesting and Aquaculture Activities
Commercial harvesting of certain fishes, invertebrates, and kelp resources may result in varied types of disturbance to wildlife. The use of nighttime lighting in the commercial squid fishery may disturb certain seabirds such as pelicans, petrels, and auklets as well as sea otters by disrupting natural behavior. The California Department of Fish and Game regulations require shielding the entire filament of all lights used to attract squid in order to reduce light scatter and decrease potential wildlife disturbance. Kelp harvesting may disturb some fauna associated with the kelp canopy, such as juvenile rockfishes and sea otters (Figure 26).
Acoustic ImpactsConcern about the cumulative impacts of noise from a variety of sources has grown as the ocean has become noisier over the past half-century. Anthropogenic sources of noise include large commercial shipping traffic, recreational and commercial vessels, military low frequency testing, and research activities. Projects like the Navy's Low Frequency Acoustics and the expansion of a Navy bombing range in Big Sur have elevated these concerns. Marine mammals have been observed to deviate from their migration paths to avoid noise, or interrupt their communications in response to elevated noise levels (reviewed in NRC 2005). Certain anthropogenic noise is thought to mask sounds used for mating, feeding and avoiding predators. Responses vary depending on the acoustic frequency, decibel level, proximity to the source and other species-specific sensitivity factors. Long-term cumulative impacts are uncertain and range from minimal impacts in some situations, to possible physical damage to hearing structures, to stranding events.
Marine DebrisLevels of debris in both the ocean and at the land-sea interface are of growing concern. Various types of debris, including lost fishing gear, plastic bags, foamed polystyrene, balloons, and other consumer goods (Figure 27), are known to have adverse effects on marine species. Ingestion and entanglement are two of the many problems associated with marine debris, and may lead to death for many organisms. Plastics in the marine environment never fully degrade and recent studies found that forms of plastic are consumed by organisms at all levels of the marine food web (Derraik 2002).
Lost fishing gear can create long-term entrapment mechanisms that continuously kill mobile fauna for many years. Net materials are constructed to be strong and resilient, thus preventing escape of entangled wildlife and persisting in the environment for decades. Lost cage traps continue to catch prey on a continuing cycle as predators enter the traps to feed on dead and dying entrapped organisms. Nets and traps can physically scrape organisms off of hard reef habitat or sweep immobile invertebrates from sandy areas.