Site History and Resources
Overview
The Monterey Bay National Marine Sanctuary (Figure 1) is the largest national marine sanctuary and one of the largest marine protected areas in the United States. The sanctuary encompasses a shoreline length of approximately 276 statute miles (240 nmi) between Marin Rocky Pt. in Marin County in the north to Cambria in San Luis Obispo County in the south (about one-fourth of the California coast). It encompasses 6,094 square statute miles (4,602 square nmi) of ocean, which is larger than the state of Connecticut (73 FR 70487).
Sharing Boundaries
Three of the 13 marine sanctuaries have contiguous boundaries. Cordell Bank, Gulf of the Farallones and Monterey Bay National Marine Sanctuaries all reside within a coastal marine ecosystem dominated by the California Current. While each has distinct features and settings, many resources are similar and some even 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.
Davidson Seamount
On Nov. 20, 2008, NOAA released final revised management plans, regulations and a joint final environmental impact statement for Cordell Bank, Gulf of the Farallones and Monterey Bay national marine sanctuaries. The plans include the expansion of Monterey Bay National Marine Sanctuary by 775 square statute miles to include the Davidson Seamount (Figure 1), one of the largest known underwater mountains in U.S. coastal waters and home to a wide variety of marine species.
In order to address the set of 17 questions related to this condition report, a workshop with local subject matter experts was convened in May 2007, and in August 2007 a draft report was reviewed by a team of peer reviewers. The comments and recommendations of these reviewers were received, considered by sanctuary staff, and incorporated, as appropriate, into a draft document prior to the release of the new management plan (more information on this process is explained in Appendix B of this report). Because input from subject matter experts and external reviewers was received before the Davidson Seamount was included as part of Monterey Bay National Marine Sanctuary, the condition report does not include a consideration of the resources contained in this undersea mountain habitat. However, these resources will be considered in future iterations of the condition report.
More information on the Davidson Seamount is available here. The final revised management plans, regulations and joint final environmental impact statement are available at here.
Within the boundaries of the sanctuary is a rich array of habitats, from rugged rocky shores and lush kelp forests to one of the largest underwater canyons in North America. These habitats abound with life, from microscopic plants to enormous blue whales. The sanctuary is home to a diversity of species including marine mammals, seabirds and shorebirds, sea turtles, fishes, invertebrates, and marine algae.
There is a substantial human dimension to the Monterey Bay sanctuary with several urban centers and approximately 3 million people living within 80 kilometers of its shoreline, many of whom rely on sanctuary resources for pleasure or work. With its great diversity of habitats and life, and due to the human communities along its shoreline, the sanctuary is a national focus for recreation, research, and education.
Maritime archaeological resources abound as well. Four hundred forty-five vessel and aircraft losses were documented between 1595 and 1950 within or adjacent to the boundary of the sanctuary (Smith and Hunter 2003). Many wrecks were a result of the significant maritime exploration and commerce that historically occurred in the region, coupled with a coastline dotted with shallow, rocky headlands, largely exposed to prevailing winds, storms, and fog. The sanctuary is responsible for the protection and management of historical and cultural resources within its boundary.
Early Settlement and Exploration
For more than 4,000 years before the arrival of the Spanish in the 1700s, the Monterey Bay region was inhabited by approximately 50 or more groups of Native Americans, collectively referred to as the Ohlone (Terrell 2007). The rich and stable environment at that time permitted the development of organized societies that used clamshell disk beads and other items as currency for trading with other groups, such as the Chumash to the south (Terrell 2007). They subsisted through collection of acorns and shellfish, and hunting of birds, fish, small mammals, seals, and sea lions (Terrell 2007). In 1603 the Spanish briefly explored and named Monterey Bay, but European settlement of the area did not begin until 1770 (Terrell 2007). The Spanish built missions at Santa Cruz, Monterey and Carmel.
Within decades of Spanish settlement, Monterey had become one of California's trade centers, with sea otter and seal pelts being one of the main trade items. Trade rapidly expanded to include Mexican, English, Russian and Yankee traders. In the mid-1800s Monterey was primarily a hub of the ranchero economy dominated by Spanish and Mexican settlers (Terrell 2007). Santa Cruz, on the northern side of the Bay, became a hub of the Yankee trade economy as the number of American and foreign settlers rose rapidly in the early decades of the 19th century (Terrell 2007). The Gold Rush economy, centered in San Francisco, spurred coastal trade and the abundant fisheries in Monterey Bay and agricultural resources of the Salinas Valley became a main commodity for the region, a pattern that continued well into the 20th century (Terrell 2007).
Designation of the Sanctuary
In 1977, the state of California nominated Monterey Bay and nine other locations along the Pacific Coast for consideration as national marine sanctuaries. Based on favorable public response, three of these sites were declared active candidates for designation: Monterey Bay, Channel Islands, and Point Reyes-Farallon Islands. This process eventually led to the designation of Channel Islands National Marine Sanctuary in 1980 and the Point Reyes-Farallon Islands National Marine Sanctuary (later renamed Gulf of the Farallones National Marine Sanctuary) in 1981. In 1983, NOAA removed Monterey Bay from its list of active candidates, recognizing that similar marine environments were already protected by California's two new sanctuaries and that a sanctuary of Monterey Bay's size would impose a heavy administrative burden on a program with limited resources.
The citizens of central California, however, would not give up on the idea of a sanctuary for their region. Following five years of grassroots campaigning, along with the dedicated support of then-Congressman Leon Panetta, Congress directed NOAA to reinstate Monterey Bay as an active candidate for sanctuary status in 1988. After another four years of public meetings and preparation of several detailed planning documents, Monterey Bay National Marine Sanctuary was officially designated on Sept. 18, 1992 (NMSP 2002).
Geology
The Monterey Bay sanctuary contains one of the world's most geologically diverse and complex seafloors and continental margins (Figure 2). The Monterey Bay sanctuary is located on a plate boundary that separates the North American Plate from the Pacific Plate and is marked by the San Andreas fault system. This is an active tectonic region with common occurrences of earthquakes, submarine landslides, turbidity currents, flood discharges and coastal erosion.
Coastal topography varies greatly, encompassing steep bluffs with flat-topped terraces and pocket beaches to the north; large sandy beaches bordered by cliffs and large dune fields around Monterey Bay; and predominately steep, rocky cliffs to the south. The Santa Cruz mountain range dominates the topography in the northern portion of the sanctuary. Two major rivers (San Lorenzo and Pajaro Rivers) and a major creek (Scott Creek) enter Monterey Bay from these highlands through well-defined valleys. Elkhorn Slough, an old river estuary that today is occupied by tidal salt marshes, extends inland as part of the sanctuary from Moss Landing for more than 10 kilometers. The broad, extensive Salinas Valley is located between the Santa Lucia and Gabilan Ranges which are the dominant topographic features in the southern region; the Salinas River is the major drainage system. South of Monterey, the west flank of the Santa Lucia Range drops abruptly into the ocean. Here, the valleys of the Carmel and Little Sur Rivers are dominant topographic features. From Point Sur to Morro Bay many streams and creeks drain the southern Santa Lucias and cut the steep western face of the mountain range.
The Monterey Bay sanctuary seafloor can be divided into three segments based on seafloor morphology. The northern segment, which lies between the southern Farallon Islands-Tomales Bay area and Point Año Nuevo, is composed of a relatively broad-shelfed, smooth and undissected seafloor. The most prominent features here are the headward parts of Pioneer Canyon, which continue from within the Monterey Bay sanctuary down the continental slope and out onto the abyssal plain west of the sanctuary boundary. The central segment extends from the Point Año Nuevo area to south of Point Sur. It contains the most geologically diverse seafloor within the Monterey Bay sanctuary. The most dramatic features are the Ascension-Monterey Canyon system, which has extensively dissected the continental shelf and slope in the Monterey Bay area, and the many heads of Sur Canyon, which have cut the continental slope just south of Point Sur. The southern segment extends from south of Point Sur to Morro Bay. Here the sanctuary averages only 25 kilometers wide, and contains a very narrow, moderately dissected continental shelf.
Commerce
There is a rich history of human use of central California's marine resources, beginning with the Native Americans and continuing to the present. Today the sanctuary's spectacular scenery, moderate climate, abundant marine life, and relatively clean ocean waters all draw large numbers of divers, kayakers, boaters, fishermen, surfers, tidepoolers, and bird and mammal watchers. Coastal tourism, agriculture, and commercial and recreational fisheries are all contributors to the regional economy with direct links to the sanctuary.
Travel and tourism is one of the most significant industries, with a total travel-spending revenue in 2003 of $5.9 billion for the five counties adjacent to the sanctuary (NOAA 2008a). Two of the main reasons given for travel to the coastal region are its natural and scenic beauty and recreational opportunities. Agriculture was valued at $3.65 billion for the region, including inland counties Santa Clara and San Benito, in 1999. Monterey County, valued at $2.44 billion, is by far the most significant producer in the region and ranks third highest statewide (NOAA 2008a). In 2007, 560 fishing vessels made commercial landings at the five main ports in or adjacent to the Monterey Bay National Marine Sactuary: Princeton/Half Moon Bay, Santa Cruz, Moss Landing, Monterey, or Morro Bay (Bob Leos, CDFG, pers. comm.). Ex-vessel revenues for landings at these five ports totaled $12.7 million paid to commercial fishers in 2007 (CDFG 2008a). Additional revenue is generated from the businesses associated with both commercial and recreational fishing operations, including packing, processing and retail sales, marinas, maintenance operations, and equipment.
Other sanctuary-related industries include aquaculture, kelp harvesting, sand mining, and commercial shipping (Figure 3). The rich biodiversity and close proximity of the deep sea also provide unparalleled research opportunities for approximately 25 marine science facilities that, in 2004, employed almost 2,000 staff and researchers with a combined budget of over $200 million (NOAA 2008a). This includes government agencies, public and private university research institutions, and private facilities such as the Monterey Bay Aquarium.
Water
The oceanography of the sanctuary is closely tied to processes of the California Current. This current is an eastern boundary current that has been characterized generally as a broad, shallow, slow southward moving current. Below this surface flow is the northward moving California Undercurrent. During the late fall and winter, the undercurrent often surfaces inshore of the California Current. This seasonal northward flow along the coast is often referred to as the Davidson Current. These currents vary in intensity and location, both seasonally and from year to year.
Each year, there are three oceanographic seasons in the sanctuary called the upwelling, oceanic, and winter storm seasons. These seasons overlap and do not follow a strict cycle. The upwelling season generally occurs from mid-March through mid-August. During this season, strong northwest winds move surface waters offshore. These waters are replaced by cool, nutrient-rich water from below. Upwelling areas can be observed as cool sea surface temperatures in satellite images (Figure 4). Two upwelling centers are located in the Monterey Bay sanctuary: one near Point Año Nuevo and one near Point Sur.
The oceanic season generally occurs from mid-August through mid-November. During this time, winds are light and variable, upwelling is not active, and offshore waters move inshore where surface water is heated by sunlight. The winter storm season generally occurs from late November through mid-March. During this period, low pressure systems moving south of the Gulf of Alaska generate southerly winds off California, along with large waves. Under the influence of these processes, the northward flow of the Davidson Current is enhanced.
The California Current system experiences large variations of the atmosphere and ocean that can strongly affect environmental conditions. The most familiar anomalies, El Niño (warm-water) and La Niña (cold-water) events, tend to last about a year and reoccur about every two to seven years. The 1997-98 El Niño event, now recognized as the strongest of the century, affected sanctuary ecosystems more than any other natural phenomenon in recent history. Another recurring pattern of climate variability, called the Pacific Decadal Oscillation, is characterized by interdecadal fluctuations in sea surface temperature and sea level pressure. Oceanographic conditions appear to have reversed around 1899, 1925, 1947, 1977, and 1998. During the cool phase the ocean off California is characterized by higher salinity, lower sea surface temperature, a shallower thermocline, stronger upwelling, a faster California Current, and elevated nutrients, primary production, and zooplankton biomass (Chavez et al. 2003). The reverse pattern characterizes the warm phase. Existing data indicate we are currently in a cool phase.
Habitats
Monterey Bay National Marine Sanctuary, which extends from the mean high water line along the coast to the offshore boundary, contains many diverse biological communities ranging from beaches and lush kelp forests in the nearshore to one of the deepest offshore underwater canyons in North America.
Coastal Wetlands and Estuaries
Coastal wetland and estuarine habitats occur in and immediately adjacent to the sanctuary. These coastal habitats support unique biological communities with both aquatic and terrestrial characteristics. Terrestrial organisms that live in estuaries must be able to tolerate high salinity, periodic inundation and desiccation, and those that are aquatic must be able to survive low concentrations of dissolved oxygen. The flow of water and organisms through coastal wetlands and estuaries helps connect the sanctuary to the adjacent terrestrial habitats.Coastal streams along the north coast of the Monterey Bay sanctuary form lagoons immediately adjacent to sanctuary waters. These coastal lagoons serve as corridors for salmon between feeding grounds in sanctuary waters and freshwater spawning grounds.
Elkhorn Slough, which harbors the largest tract of tidal salt marsh in California outside of San Francisco Bay, is an ecological treasure at the center of the Monterey Bay coastline. There are dozens of algae and plant species, over 100 fishes, more than 340 bird species, and over 550 invertebrate species that inhabit the slough (Caffrey et al. 2002). The relative rarity of estuarine habitats along the Pacific coast makes Elkhorn Slough's role in supporting species dependent on estuarine habitats essential. This estuary also serves as a spawning and nursery ground for some marine fish species, such as leopard sharks, California halibut and English sole. The main channel of Elkhorn Slough, which snakes more than 10 kilometers inland, is the only estuarine habitat located inside the boundaries of the Monterey Bay sanctuary (Figure 5).
Human activity and coastal development have negatively impacted many estuarine and lagoon habitats. For example, over the past 150 years, human actions have altered the tidal, freshwater, and sediment processes that are essential to support and sustain Elkhorn Slough's estuarine habitats. The cumulative impacts of these actions have been to convert Elkhorn Slough into a tidal wetland with strong daily tidal currents and substantially altered distribution of estuarine habitat types. Major threats to estuarine habitats result from increased rates of tidal erosion, marsh drowning, and dikes (Caffrey et al. 2002). The accelerated rate of bank and channel erosion is causing tidal creeks to deepen and widen, salt marshes to collapse into the channel and die, and soft sediments to be eroded from channel and mudflat habitats.
Nearshore
Beaches are one of the most visible and popular sanctuary habitats. Every year travelers from around the world come to enjoy the natural scenery, wildlife, and recreation that sanctuary beaches offer (Figures 6 and 7). Beach habitats include long exposed beaches, protected pocket beaches, and transient beaches, which are eroded to bedrock in the winter, then reappear during summer when wave energy is reduced. Sand in the Monterey Bay sanctuary is derived from several sources, including alongshore transport, local erosion of cliffs, and transport down local rivers. Sand transport along the open coast is generally from north to south, as a result of the prevailing northerly winds. However, this is only an average trend, as periodic reversals of alongshore transport in response to storms from the south can result in significant sporadic northward transport. Sand beaches are very harsh environments, with high wave action, high abrasion levels and lack of firm substrate for attachment. Beach fauna exhibit the characteristics of communities in harsh environments, namely low species diversity but high abundance.
Rocky shores are one of the sanctuary's most accessible habitats and, at low tide, a wide diversity of organisms are exposed for humans to enjoy. The accessibility of organisms attracted early marine ecologists, and the experimental field methods they developed have influenced the study of ecology well beyond the marine realm. One reason that rocky shores have received such keen scientific attention, particularly in the sanctuary region, is their extensive, and highly structured, biological diversity. Different species assemblages grow in distinct zones that vary with tidal height, wave exposure, and a variety of other physical and biological factors. The physical setting of the sanctuary region may explain the relatively high biodiversity found on its rocky shores: substantial tidal range (2.3 m), upwelling of nutrient-rich water, and fog associated with upwelling that prevents desiccation during low tides in otherwise dry summer months. The extent of rocky shoreline habitat in the sanctuary is estimated to cover 2 to 7 square miles, making it one of the rarest habitats in the sanctuary (P. Raimondi, UCSC, per. comm.).
One of the most recognizable elements of the nearshore environment is the kelp community. The sanctuary's rocky nearshore environment is characterized by forests of giant kelp and bull kelp that occur on rocky substrates at depths of two to thirty meters (Figure 8). Like terrestrial forests, kelp forests consist of multiple layers. Below the surface canopy is the understory, a layer one to two meters above the bottom that is dominated by stalked brown algae and fleshy red algae. The lowest layer, turf algae, consists of several red algae rising only a few centimeters above the rocky bottom.
By providing vertical structure in the waters above the rocky reef, kelp forestsprovide a unique, living habitat that is utilized by numerous species, including marine mammals, fishes, other algae, and vast numbers of invertebrates. Though some large kelp species can persist for up to three years, the overall structure of the kelp forest is very dynamic. It has long been known that kelp populations in the sanctuary exhibit seasonal patterns of abundance, with maximum surface canopies in early fall and minimum canopies in winter.
Nearshore soft bottom areas, composed of loose sand and mud sediments, are the most extensive bottom habitats in the sanctuary and one of the least studied. Two major groups of invertebrates are found in this habitat: 1) the infauna, which live buried within the sediment (about 90 percent of all the bottom-dwelling organisms); and 2) the epifauna, which live on or move over the bottom. The subtidal invertebrate fauna of the shallow offshore waters are far more diverse than intertidal fauna. However, less is known about these subtidal species. The dominant invertebrates in shallow subtidal waters are worms, clams, snails, crabs, and other crustaceans.
Deep Sea
The deep-sea environment starts below 1,000 meters and extends to the seafloor. This cold realm of total darkness and immense pressure is poor in nutrients and dissolved oxygen. The deep sea is populated by a wide array of animals, specially adapted to live under the tremendous water pressure and low oxygen levels found in this habitat. Deep-sea animals, such as the big red jelly (Figure 9), typically have small eyes or no eyes at all, but instead rely on other highly developed senses to find mates and food and to escape predators. Unlike most communities on Earth that rely on sunlight as a primary energy source, deep sea communities derive energy by eating debris that sinks from the surface layer or by creating chemical energy from fluids that seep from the seafloor.Submarine canyons are prominent geomorphic features within the Monterey Bay National Marine Sanctuary. One of the deepest and largest submarine canyons on the coast of North America is the Monterey Canyon, located in the center of Monterey Bay. Similar in size to the Grand Canyon in Arizona, it is 470 kilometers long and approximately 12 kilometers wide at its widest point, with a maximum rim-to-floor relief of 1,700 meters. Numerous smaller canyons cut into the continental shelf and slope, especially along the Big Sur coastline. Submarine canyons are ecologically important to many species. For example, canyons provide habitats for larger sized rockfish that seem to prefer structures of high relief such as boulders, vertical walls, and ridges. Submarine canyons are also foraging areas for marine mammals and birds that eat the large schools of prey, such as krill, that can congregate in the canyon head or along canyon edges.
Offshore Waters
In the offshore surface waters of the sanctuary (from the surface to 200 meters depth), food webs are supported almost entirely by phytoplankton (tiny plants). Zooplankton (tiny animals such as fish larvae and krill) and small schooling fishes (e.g., anchovy and sardine) are a major food source in the open waters of the sanctuary, and their abundant populations draw many birds, fishes, and whales to the area. In the midwater environment (from 200 to 1,000 meters) light, nutrients, and dissolved oxygen diminish and water pressure increases with depth. Midwater fishes and some invertebrates have developed large and elaborate eyes that allow them to see under the low-light conditions in this environment. Many small midwater fishes and zooplankton, including krill, feed on phytoplankton by migrating hundreds of meters to the surface layer after sunset. At dawn, they return to their midwater habitat.The midwater habitat and its inhabitants are currently being studied with remotely operated vehicles (ROVs) to develop a dynamic model of the community (Figure 10). Initial data show positive coupling between the seasonal cycles of productivity by phytoplankton and the abundance cycles of gelatinous predators (jellyfish) that feed on phytoplankton grazers.
Living Resources
Flowering Plants and Algae
A diverse group of photosynthetic organisms exploits the shallow margins of wetlands where they receive high levels of sunlight and nutrients. Algae, such as sea luttuce, grow in the high intertidal flats. Eelgrass, a flowering vascular plant, occurs in protected waters, including patches in all larger bays and estuaries off central and northern California. Salt marshes develop along the shores of some protected river mouths and estuaries. A variety of herbaceous plants, including pickleweed, saltgrass, cattails, sedges, and rushes, grow along the margins of salt marshes.
Along the rocky coast, certain types of algae tend to be found in different tidal height zones based on exposure to air during low tides. Rockweeds, a group of brown algae, and low growing, bushy red algae are the most common indicators of the high intertidal zone. Dense patches of upright, calcified forms of red algae, called coralline algae, typically dominate the middle intertidal zone. The presence of surfgrass and small kelp species, such as the sea palm and feather boa kelp, are indicators of the low intertidal zone (Figure 11).
In the subtidal zone, a rich algal assemblage is associated with the kelp forest. Beneath surface canopies formed by giant and bull kelp are several species of understory kelp. Other algae, such as fleshy red species, can form dense algal turfs under the canopies and are often distributed along a depth gradient with the more robust species occurring shallower and the more delicate species occurring deeper. Coralline algae occur throughout the kelp forests and are generally more tolerant of increased water motion and thus abundant in exposed sites.
Invertebrates
The invertebrate assemblage in the sanctuary is extremely diverse. More than 2,500 species of invertebrates are known to inhabit the beaches and rocky shorelines of the Monterey Bay region (J. Pearse, UCSC, pers. comm.) and 204 species of invertebrates were found living in one kelp forest along the exposed coastline south ofCarmel. Some groups of sedentary and sessile invertebrates, such as anemones and tube worms, occur in both the soft-bottom and rocky reef habitats while other groups (e.g., mussels, barnacles, sponges, tunicates, corals) are found primarily attached to hard structure or only in soft sediments (e.g., sea pens, sea whips, clams). Invertebrates that are more mobile, such as snails (Figure 12), sea stars, sea urchins, octopus, and crabs, prefer either rocky or soft bottom habitats, but are capable of moving between these different habitat types. Soft bottom habitats also contain a diverse assemblage of infaunal invertebrates (animals that live buried in the sediment) dominated by polychaete worms and small crustaceans. Invertebrates in open water habitats range from solitary active predators (e.g., large squid and octopus), to densely schooling forms (e.g., krill and market squid), to gelatinous suspension feeders and filter feeders (e.g., salps, comb jellies, larvaceans). The Monterey Bay Aquarium Research Institute has cataloged approximately 771 species of invertebrates living in the midwater and on the surface of the deep seafloor and 1,200 infaunal species in the Monterey Bay National Marine Sanctuary, including Davidson Seamount (J. Connor, MBARI, pers. comm.).
Fishes
Hundreds of species of fishes are found in the sanctuary. Fish assemblages can be categorized according to where they reside. Estuaries and lagoons support a distinctive assemblage of fish species that tolerate a variety of salinity conditions. Some species (e.g., flatfishes, sharks and rays) use estuaries during the juvenile phase, but move out onto the continental shelf as they mature. A number of small and specialized fishes, such as gunnels, pricklebacks, and tidepool sculpins, are found in tide pools along the rocky coast. Rockfishes (genus Sebastes) compose a very diverse group found in many subtidal habitats in the sanctuary, but they are especially common on rocky reefs (Figure 13). Flatfishes (sole, halibut, flounder, turbot, and sanddab), skates and rays, sablefish, and Pacific hake are typical of soft bottom habitats on the shelf and upper slope. Most deep-sea bottom fishes off central California belong to one of four families: grenadiers, eelpouts, codlings, and skates. The open waters of the sanctuary are occupied by a large diversity of pelagic fishes ranging from small schooling fishes (e.g., anchovy, sardine, mackerel, and mesopelagic fishes like lanternfishes, deep-sea smelts, and bristlemouths) to large solitary predators (e.g., tuna, sharks).Sea Turtles
The leatherback is the only species of sea turtle that is commonly observed in the sanctuary. The leatherback is the largest turtle in the world and it is found in all of the world's major oceans. Leatherbacks are also one of the deepest diving air-breathing animals known - descending to depths in excess of 1,300 meters. Annual aerial surveys along the central California coast indicate that leatherbacks are most common in the sanctuary during summer and fall when jellyfish, which are the major prey items of leatherback turtles, are seasonally abundant. Leatherback turtle populations in the Pacific Ocean are declining at a precipitous rate and the accidental killing of leatherbacks by high seas commercial fishing fleets is a major contributor to that decline.
Seabirds and Shorebirds
Sanctuary waters are among the most heavily used by seabirds worldwide (Figure 14). Ninety-four species of seabird are known to occur regularly within and in the vicinity of the nearshore and offshore environments of the sanctuary, and approximately 346 species of birds are known to visit or live in Elkhorn Slough. Several environmental features are responsible for the diverse assemblage ofbirds in the area. Monterey Bay is located on the "Pacific Flyway," allowing migratory birds a place to stopover during both north and south migrations between southern wintering grounds and northern breeding sites. The upwelling of nutrient-rich waters supports highly productive food webs, which provide abundant prey, as well as the diversity of habitat types along the shore, which increases the variety of bird species utilizing the sanctuary. Thus, many birds found in sanctuary waters have come to feed, some from as far as New Zealand.
Marine Mammals
The sanctuary has one of the most diverse and abundant assemblages of marine mammals in the world, including six species of pinnipeds (seals and sea lions), 27 species of cetaceans (whales, dolphins, and porpoises), and one fissiped (sea otter). Presently, approximately 82% of the southern sea otter population occurs within the sanctuary (Tinker et al. 2006).Five species of pinnipeds commonly occur in the Monterey Bay National Marine Sanctuary. Four of these species - California sea lions, Steller sea lions, northern elephant seals, and Pacific harbor seals (Figure 15) - are observed frequently along the coast because they use rocky shorelines and beaches to rest and give birth. The northern fur seal is seasonally abundant in the sanctuary, but usually found in offshore waters. An additional species, the Guadalupe fur seal, has been reported from records of sick animals stranded on the beach.
Of the 27 species of cetaceans seen in the Monterey Bay area, about one-third occur frequently. Most of the cetaceans in the sanctuary are highly transitory, although some individuals may be residents within the area. The large baleen whales either migrate through the sanctuary (e.g., gray whales) or move into the area seasonally to feed (e.g., blue and humpback whales). Movements of smaller cetaceans probably are associated with changes in prey abundance and oceanographic conditions. Of the sanctuary's cetacean population, blue, humpback, and gray whales and harbor porpoises have been monitored regularly. Other cetacean populations are assessed less frequently.
Endangered and Threatened Species
Twenty-six species that use resources in the sanctuary are listed by the U.S. federal government as endangered or threatened. Eleven of these species (including multiple populations for steelhead and Chinook salmon) have been placed on the federal list of endangered and threatened wildlife since sanctuary designation in 1992. Examples of these more recently listed species are the Western Snowy Plover, winter and spring runs of Chinook salmon, central coast and south central coast steelhead, tidewater goby, and black abalone. A few species bring a hopeful sign for the future: the gray whale, American Peregrine Falcon, and Bald Eagle were delisted in 1994, 1999, and 2007, respectively; and the California Brown Pelican is proposed for delisting.Maritime Archaeological Resources
Submerged archaeological resources include shipwrecks, aircraft, wharves and dock sites, prehistoric archaeological sites, and associated artifacts. Hundreds of shipwrecks have occurred in the Monterey Bay National Marine Sanctuary, and were a result of the significant maritime exploration and commerce that historically occurred in the region, coupled with a coastline dotted with shallow, rocky headlands, largely exposed to prevailing winds, storms, and fog. The sanctuary is responsible for the protection and management of historical and cultural resources within its boundary. Sanctuary stewardship responsibilities include a mandate to inventory sites, encourage research, provide public education, and oversee responsible visitor use.
In 2003, the Monterey Bay National Marine Sanctuary archaeology database contained 445 reported losses of vessels and aircraft located in Pacific waters directly within or on the border of the sanctuary (Smith and Hunter 2003). One of the most historically significant wrecks in the sanctuary is the USS Macon (Figure 16). The USS Macon, a 785-foot dirigible carrying four Sparrowhawk biplanes, was lost offshore of Point Sur on February 12, 1935. For decades the underwater location remained a mystery. In 1990 and 1991, the Monterey Bay Aquarium Research Institute and the U.S. Navy located the Macon's remains at a depth of over 1,000 feet. In 2005 and 2006, a team of scientists, including sanctuary staff, conducted a side-scan sonar survey at the wreck site, and an ROV survey was used to record artifacts and create a photo mosaic of the site. The Macon expedition marks the sanctuary's first archeological survey within the boundary of the sanctuary. The remains of the Macon provide an opportunity to study the relatively undisturbed archeological remnants of a unique period in aviation history.