Monterey Bay National Marine Sanctuary






Sancutary Program Accomplishments

Intertidal Systems

Rocky Subtidal Systems

Open Ocean & Deep Water Systems

The Physical Environment

Wetlands and Watersheds

Endangered & Threatened Species

Marine Mammals

Bird Populations

Harvested Species

Exotic Species

Human Interactions

Further Reading


Restoring Common Murre Colonies

Scientists are working to restore Common Murre colonies at several sites throughout the Sanctuary. (©California Department of Fish & Game)

Between 1980 and 1986 Common Murre colonies between Marin and Monterey Counties declined drastically, due to mortality in gillnets and oil spills and low breeding success during the 1982-83 El Niño —as much as 45.8 percent along the Big Sur coast (Castle and Hurricane Point rocks). One major impact was the extermination of murres at Devil's Slide Rock (DSR) in San Mateo County following the 1986 Apex Houston oil spill. This spill killed 9,000 seabirds, including 6,000 Common Murres. Settlement of a federal case against the potentially responsible party established a Trustee Council with representatives from the U. S. Fish and Wildlife Service, NOAA, and California Department of Fish and Game to oversee restoration of natural resources injured by the spill.

Since 1996 the Council, along with the San Francisco Bay National Wildlife Refuge Complex, Humboldt State University Foundation, National Audubon Society, and U.S. Geological Survey, has been conducting a Common Murre restoration project in central California. The main goal is to restore exterminated murre colonies using social attraction. Specifically, biologists are using decoys, recorded murre calls, and mirrors to attract murres to DSR and San Pedro Rock (SPR), both in San Mateo County. Castle and Hurricane Point rocks have been targeted for potential restoration efforts, also. However, limited information was available concerning murre biology at these colonies, so intensive monitoring is being conducted to evaluate the best restoration options there.

In January 1996 restoration efforts began at DSR when nearly 400 decoys, 12 three-sided mirror boxes, and 2 independent sound systems were deployed. That year, the colony had a peak count of 29 murres: 6 pairs laid eggs and 3 chicks fledged. The colony has continued to grow and even produced chicks during the severe 1998 El Niño event. In 1999 numbers grew substantially—with a peak count of 137 murres, breeding numbers increased to 70 pairs, and 59 chicks fledged.

In April 1998 social attraction equipment was placed on SPR. A slower response has been seen here, with a peak count of 26 murres landing during the past 2 years and no documented breeding. Murres last bred on SPR in 1908, so we expect it will take longer to recolonize this site compared to more recently destroyed sites.

Restoration efforts along the Big Sur coast present a different challenge. First, the colonies are an assemblage of near shore rocks and mainland cliffs at three colony locations. Also, there may be several human-caused factors, unique to this area, that are limiting the recovery of the colonies (e.g., gillnet mortality, disturbances).

Over the past four years we have documented disturbances by fishing boats, aircraft, and natural causes that result in adult murres flushing from their breeding sites and exposing their eggs and chicks, which are then preyed upon or dislodged into the ocean. In 1999 several events impacted the murre colonies. On April 25, murres were documented being flushed fourteen times during aircraft filming of the Big Sur Marathon. Although no eggs were documented being lost, this event may have delayed the onset of egg laying, reducing reproductive success. On June 18 an immature Brown Pelican landed among one of the largest subcolonies. All adult murres were flushed, resulting in the loss of at least nine eggs and seven chicks from our study plot. A third impact occurred repeatedly over several weeks in July. Commercial fishing boats, conducting operations within meters of the breeding colonies, unknowingly caused adults murres to flush from the colonies, resulting in many eggs and chicks being lost. We are working with Sanctuary staff and law enforcement agencies by providing this disturbance information to them and educating pilots and boat captains whenever possible. More concerted educational efforts may prevent these types of human-caused disturbances in the future.

Ultimately, the restoration and monitoring activities taking place within the Sanctuary will help ensure the long-term persistence of these important murre colonies.

--Michael W. Parker
San Francisco Bay National Wildlife Refuge,
U.S. Fish and Wildlife Service


The Moss Landing Christmas Bird Count: A 24-Year Summary

The National Audubon Society sponsored its 100th annual Christmas Bird Count between December 16, 1999 and January 3, 2000. These counts, which include over 1,700 areas throughout North America, utilize volunteers to survey a 15-mile diameter circle during one calendar day within a two-week period centered on Christmas Day.

The first Moss Landing Christmas Bird Count (MLCBC) was held on January 2, 1976; its date was changed to January 1 in 1977. The count includes the city of Pajaro; the beach-front communities from La Selva Beach to Moss Landing; the agricultural areas around Corralitos, Aromas, and Prunedale; and the extensive system of lakes, ponds, and sloughs scattered throughout this region. The total number of species recorded on count day has ranged from 175 species (in 1977) to 214 species (in 1988); the cumulative total number of species seen for all years is 294. The daily totals have consistently been within the top 10 counts nationally during MLCBC's 24-year history. The highest total number of individuals seen was 135,514 in 1988; the lowest number seen was 63,207 in 1976. On our January 1, 1999 count, 87 observers identified 204 species and tallied 84,359 individual birds.

The main environmental factor that distinguishes the MLCBC from neighboring counts is the extensive wetlands associated with Elkhorn Slough and the myriad bird populations that this ecosystem supports. The Western Hemisphere Shorebird Reserve Network has designated Elkhorn Slough as a site of regional importance for shorebirds—that is, a wetland that supports at least 20,000 shorebirds at some time during a year.

During its 24-year history, the MLCBC has reported 30 shorebird species within the Elkhorn Slough area; 22 species of shorebirds are regularly seen in this area each year. Over the past 10 years, the total number of shorebirds in the main channel of Elkhorn Slough and the adjacent ponds of the Moss Landing Wildlife Management area has ranged from 33,435 individuals in 1990 to 6,496 individuals in 1999. The 13 most abundant species (based on median values) were the Western Sandpiper, Least Sandpiper, Dunlin, Marbled Godwit, Willet, American Avocet, Long-Billed Dowitcher, Black-Bellied Plover, Short-Billed Dowitcher, Long-Billed Curlew, Sanderling, Black-Necked Stilt, and Semipalmated Plover. Western Sandpipers represented 38 percent to 59 percent of the total number of shorebirds, and the "peeps" (Western Sandpiper, Least Sandpiper, and Dunlin) accounted for 79 percent to 93 percent of the total number of shorebirds.

In his introduction for the American Birds 88th Christmas Bird Count issue, Geoffrey LeBaron writes: "If I had my druthers, which count would I have been on last year? Edmonton, Alberta? Orange County or Moss Landing in California?" The continued protection of our precious resources afforded by the Monterey Bay National Marine Sanctuary will ensure that people can ponder this question in centuries to come.

--Bernadette Ramer
--Bob Ramer, Santa Cruz Bird Club

Seabirds within Monterey Bay--Observations of the Quick and the Dead

Figure 1: Beach segments within Monterey Bay sampled by Beach Combers volunteers and representative grid of offshore transect lines.

Seabirds are excellent indicators of ecosystem health because they are large, easily counted, and consumers of important trophic level species such as krill, anchovies, and squid. A beach monitoring study, utilizing volunteers sampling selected sections of beach for dead seabirds, was established within the Monterey Bay National Marine Sanctuary in May 1997. The primary goal of the program, designated Beach COMBERS (Coastal Ocean Mammal / Bird Education and Research Surveys) was to obtain information on stranding rates for all species of seabirds and marine mammals.

During 1999 Beach COMBERS volunteers counted and marked beachcast seabirds monthly within designated beach segments, covering 51 km of sandy beaches within and around Monterey Bay (Figure 1). Because the presence and abundance of seabirds at sea is variable and affects beachcast data, monthly pelagic surveys of seabirds were conducted from May-October aboard the R/V John Martin along a random grid of transect lines, spaced at 5.6 km intervals. All seabirds within 100 m of the ship were counted.

Counts of beachcast seabirds during January-October 1999 were five times lower and less variable than during the same period in 1998, an El Niño year. The greatest deposition occurred during October and was dominated by Common Murres (Figure 2). Densities of live birds within the bay were highest during May, when large surface aggregations of krill were encountered. Seabird assemblages at sea were dominated by Sooty Shearwaters in every month except October. Post-breeding Common Murres were abundant during August. Despite the overwhelming densities of live Sooty Shearwaters in the bay, relatively few were beachcast. In contrast, Common Murres appeared to be over-represented on the beach relative to their densities in the water. The reason for this pattern was not clear because the cause of death of encountered beachcast seabirds was rarely known. Post-breeding Common Murres are flightless and capable of diving to depths ranging from 50 to 180 m to feed themselves and their chicks. This behavior may subject them to mortality uncommon to other seabird species, such as entanglement in halibut set gillnets (see related article in Harvested Species Section).

Figure 2: Results of Beach COMBERS survey (top figure) and at-sea counts (bottom figure) of seabirds during 1999.

Beach COMBERS volunteers are collecting fresh beachcast seabirds for necropsy by personnel at the state's Oil Spill Prevention and Response facility in Santa Cruz. These samples, combined with birds taken incidentally in the local set gillnet fishery, will improve our ability to assess causes of death and increase our understanding of the health of nearshore habitats. We greatly appreciate the dedication of the many highly skilled volunteers who make this monitoring project possible.

--Scott R. Benson
Moss Landing Marine Laboratories

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Last modified on: March 31, 2000