Wildlife Health
Greater Farallones

researcher collecting phytoplankton from the side of a ship
A graduate student on an Applied California Current Ecosystem Surveys (ACCESS) research cruise collects a phytoplankton sample for the early detection of biotoxins and harmful algal blooms. This study is lead by the state Department of Public Health. Credit: J. Roletto, ACCESS/Pt Blue/ONMS

Why is it a concern?

Much of the research and monitoring in the sanctuary targets issues and understanding of predator prey relationship between birds, mammals, and ecosystem integrity, and understanding the importance of the sanctuary to the recovery and growth of these species.  The health of pinnipeds and seabirds is impacted by accumulation of toxins such as organochlorines and domoic acid (a neurotoxin produced during harmful algal blooms that can cause physiological damage). These toxins are filtered from the water by plankton and various filter-feeding invertebrates, from which point they move up the food chain and become concentrated in organisms such as marine mammals and seabirds. The condition of some key species, like seabirds and salmon, changes with natural environmental variation, such as oceanographic changes that seasonally affect krill abundance and changes in prey abundance that affect fecundity and juvenile survival rates.  Monitoring productivity and mortality rates and causes are targeted studies to better understand the natural variability and resiliency of seabirds and marine mammals in the sanctuary.

There are some resources in the sanctuary that do not appear to be in optimal condition Recent observations of gray whales in their breeding areas suggest declining weights may be due to poor food availability and changes in the extent of ice cover in the Bearing Sea. Pupping rates and general population health of Steller sea lions in California have decreased since the 1950s, even though the eastern population, which includes the sanctuary, have recently been delisted from the Endangered Species List. The breeding population at the Farallon Islands has stabilized in recent years, but remains depressed.

Other key species in the sanctuary do not seem to be diminished in condition. This may be attributable, in part, to management actions that have reduced oil pollution from chronic sources and acute sources since designation of the sanctuary in 1981. Management actions, such as vigilance, enforcement of regulations and penalties for adequate restoration and mitigation have been followed by stabilization or increase of some marine mammals (elephant seals and other seals), and an apparent improvement in seabird populations in the sanctuary.

The health and integrity of the benthic habitats of the sanctuary are also of importance to sanctuary management.  In recent years the sanctuary as increased our exploration efforts to map and quantify deep-sea corals, sponges and associated fish communities.  Data from these research efforts are used to identify areas where additional protections to sensitive and valuable resources are needed.

Overview of Research

Research conducted by Sanctuary scientists and partners provides critical information to address existing and emerging resource conservation and management issues. The Overview of Research highlights some, but not necessarily all, of the research activities completed or ongoing at the Sanctuary.

Science Needs and Questions

The best available science is used by Sanctuary scientists and managers working to address priority resource conservation and management issues. As priorities change and new issues emerge, each Sanctuary develops new science needs and questions and works with partners to address them.

  • What are the status and trends of breeding bird and pinniped colonies in the sanctuary?
  • Which colonies are impacted by human disturbances?  What are the disturbances, and how might they be affecting long-term health of these species?
  • What are the influence of the predator-prey relationships of birds, mammals, and fish in the sanctuary?  Which natural influences can be mitigated?  Which anthropogenic influences can be reduced or eliminated?  What studies will help assess effectiveness of the management actions?
  • What impact will the transition to ecotourism have on marine mammal breeding and juvenile survival?

Education and Outreach Material

Education exhibits, programs and products focus on wildlife disturbance.

  • GFNMS Visitor Center Exhibits: On Seabirds and Otters discuss wildlife disturbance
  • Products: Marinelife Etiquette pocket card; Beach Wrack Card
  • Programs: Sanctuary Exploration Series, offers monthly fieldtrips for the public to experience their national marine sanctuary. Wildlife etiquette is a key program concept in all fieldtrips.
  • Boater and air plane pilot education on how to view wildlife and recreate within the sanctuary while reducing or eliminating disturbance to seabirds.


Ainley, D.G., H.R. Huber, R.P. Henderson, T.J. Lewis. 1977. Studies of marine mammals at the Farallon Islands, California, 1970-1975. Final report to the Marine Mammal Commission, Washington D.C. NTIS publication number PB274046. Available from Point Reyes Bird Observatory, 4990 Stinson Beach, CA 94970.

Calambokidis et al. 2001Calambokidis, J., T. Chandler, L. Schlender, K. Rasmussen, G.H. Steiger, and N. Black. 2001. Abundance and movements of humpback and blue whales off California using photographic identification. Unpublished Report: Proceedings of the Sixth Biennial Workshop on Research in the Gulf of the Farallones. Gulf of the Farallones National Marine Sanctuary. San Francisco, CA. 25 October 2001.

Etnoyer, P. J., G. Cochrane, E. Salgado, K. Graiff, J. Roletto, G. Williams, K. Reyna, and J. Hyland. 2014. Characterization of deep coral and sponge communities in the Gulf of the Farallones National Marine Sanctuary: Rittenburg Bank, Cochrane Bank and the Farallon Escarpment. NOAA Technical Memorandum NOS NCCOS 190. NOAA National Centers for Coastal Ocean Science, Charleston, SC. 32 pp.

FMSA (Farallones Marine Sanctuary Association). 2006. Beach Watch 2006 Annual Report .20pp. Jensen and Silber 2003.

Moore, M. , C. Miller, M. Morss, R. Arthr, W. Lange, K. Prada, M. Marx, E. Frey. 2001. Ultrasonic measurement of blubber thickness in right whales. J. Cetacean Research and Management Spec. Iss. 2:301-309.

Perryman, W.L., M.A. Donahue, P.C. Perkins, S.B. Reilly. 2002. Gray whale calf production 1994-2000: are observed fluctuations related to changes in seasonal ice cover? Mar. Mamm. Sci. 18(1): 121-144.

Rojek, N.A., M.W. Parker, H.R. Carter, and G.J. McChesney. 2007. Aircraft and vessel disturbances to Common Murres, Uria aalge, at breeding colonies in Central California, 1997–1999. Marine Ornithology 35(1): 67–75.

Roletto, J., S. Kimura, N. Manning-Cosentino, R. Berger, and R. Bradley.  In Press.  Status and trends of the rocky intertidal community on the Farallon Islands.  Western North America Naturalist,

Roletto, J., J. Mortenson, I. Harrald, J. Hall, L. Grella. 2003. Beached bird surveys to detect chronic oil pollution. Marine Ornithology 31(1):21-28.

Sydeman, W.J. and S.G. Allen. 1997. Trends and oceanographic correlates of pinniped populations in the Gulf of the Farallones, California. Administrative Report to NOAA, National Marine Fisheries Service, La Jolla, CA.

Tenera Environmental. 2003. A comparative intertidal study and user survey, Point Pinos, California. Submitted to the Monterey Bay Sanctuary Foundation, Monterey, California. Electronic document available from: https://nmsmontereybay.blob.core.windows.net/montereybay-prod/media/research/techreports/pointpinos.pdf

Tenera Environmental. 2004. James V. Fitzgerald Marine Reserve: resource assessment. Submitted to the San Mateo County Environmental Services Agency. San Mateo, California. Electronic document available from: http://www.co.sanmateo.ca.us/vgn/images/portal/cit_609/38/2/245088843resource_assessment_1.pdf

Van De Werfhorts, L.C. and J.S. Pearse. 2007. Trampling in the rocky intertidal of Central California: a follow-up study. Bulletin of Marine Science 81(2):245-254(10).