Environmental Initiatives



James Estes is an international expert on sea otters and a specialist in the critical role of apex (top level) predators in the marine environment. He has been a research biologist at the Western Ecological Research Center of the U.S. Geological Survey for more than 20 years. Estes also holds academic posts as research associate and adjunct professor with the Center for Marine Studies at the University of California, Santa Cruz.

His interest in predation as an ecosystem-level process began in the early 1970s, shortly after Estes began working with sea otters. Using the otters' fragmented distribution across the Aleutian archipelago, which resulted from a history of near-extinction and recovery, he and his colleague, Dr. Palmisano, discovered the species' keystone role in kelp forests by contrasting islands where it was abundant or rare. Their work on sea otters provided one of the first and foremost spectacular examples of how apex predators influence ecosystem functions. These early findings led Estes to explore the spatial, temporal and functional dimensions of sea otter-kelp forest interactions over the next 30 years.

He has now published nearly 70 scientific articles and reports on wildlife ecology, predation and conservation. Estes' most recent research addresses the unanticipated collapse of sea otters and kelp forests in western Alaska.



Ph.D., University of Arizona
1974 - Biology/Statistics, Arizona, USA

Masters of Science, Washington State University
1969 - Zoology, Washington, USA

Bachelor of Arts, University of Minnesota
1967 - Zoology/Chemistry, Minnesota, USA


Board of Editors

Board of Editors

American Society of Mammalogists, Standing Committee on Marine Mammals
1979-1982- Co-Chairman

US/USSR Program for Conservation of the Environment, Marine Mammal Subgroup
1976- 1979- Steering/Planning Committee

IUCN, Species Survival Commission, Otter Specialist Group
1981- Deputy Chairman

IUCN, Species Survival Commission, Otter Specialist Group
1977-present- Member


1999 - Pew Fellows Program in Marine Conservation

Distinquished Alumnus Award
1990 - University of Arizona

Natural Resource Response Award for Exceptional Service
1990 - U.S. Dept. of the Interior

Betty S. Davis Conservation Award
1987 - Friend of the Sea Otter


American Association for the Advancement of Science

Ecological Society of America

Society for Conservation Biology


Anthony, R.G., Estes, J.A., Ricca, M.A., Miles, A.K. and Forsman, E.D. 2008. BALD EAGLES AND SEA OTTERS IN THE ALEUTIAN ARCHIPELAGO: INDIRECT EFFECTS OF TROPHIC CASCADES. Ecology 89(10): 2725-2735.

Croll, D.A., Maron, J.L., Estes, J.A., Danner, E. M., and Byrd, G. V. 2005. Subarctic islands from grassland to tundra. Science 307

J.A. Estes; E.M. Danner; D.F. Doak; B. Konar; A.M. Springer; P.D. Steinberg; M.T. Tinker; and T.M. Williams. 2004. Complex Trophic Interactions in Kelp Forest Ecosystems. Bulletin of Marine Science 74(3): 621-638

A. M. Springer, J. A. Estes, G. B. van Vliet, T. M. Williams, D. F. Doak, E. M. Danner, K. A. Forney, and B. Pfister. 2003. Sequential Megafaunal Collapse in the North Pacific Ocean: An Ongoing Legacy of Industrial Whaling

Carr. M.H., Neigel, J.E., Estes, J.A., Andelman, S., Warner, R.W., and Largier, J.L. 2003. Comparing Marine and Terrestrial Ecosystems: Implications for the Design of Coastal Marine Reserves. Ecological Applications 13(1): S90-S103

Estes, J. 2003. From Killer Whales to Kelp: Food Web Complexity in Kelp Forest Ecosystems. Wild Earth 12(4): 24-28

Estes, J.A., M.L. Riedman, M.M. Staedler, M.T. Tinker and B.E. Lyon. 2003. Individual variation in prey selection by sea otters: patterns, causes and implications. Journal of Animal Ecology 72(1): 144-155

Konar, B. and J.A. Estes. 2003. The stability of boundary regions between kep beds and deforested areas. Ecology 84(1): 174-185

Gelatt, T.S., D.B. Siniff and J.A. Estes. 2002. Activity patterns and time budgets of the declining sea otter population at Amchitka Island, Alaska. Journal of Wildlife Management 66(1): 29-39

J.M. Scott, F.W. Davis, R.G. McGhie, R.G. Wright, C. Groves and J. Estes. 2001. Nature reserves: do they capture the full range of America's biological diversity? Ecological Applications 11(4): 999-1007

Jackson, J.B.C., M.X. Kirby, W.H. Berger, K.A. Bjorndal, L.W. Botsford, B.J. Bourque, R.H. Bradbury, R. Cooke, Erlandson, J. Estes, T.P. Hughes, S. Kidwell, C.B. Lange, H.S. Lenihan, J.M. Pandolfi, C.H. Peterson, R.S. Steneck, M.J. Tegner, R.R. Warner. 2001. Historical overfishing and the recent collapse of coastal ecosystems. Science 293:629-637

Estes, J.A. and C.H. Peterson. 2000. Marine ecological research in seashore and seafloor systems: accomplishments and future directions. Marine Ecology - Progress Series 195:281

Hanni, K.D., J.K. Mazet, F.M.D. Gulland, J. Estes, M. Staedler, M.J. Murray and D. Jessup. 2000. Hematologic and serum biochemical reference ranges and serologic survey in southern (Enhydra lutris nereis) and northern (Enhydra lutris kenyoni) sea otters.. Presented at: Annual Conference-- American Association of Zoo Veterinarians

Monson D.H., J.A. Estes, J.L. Bodkin and D.B. Siniff. 2000. Life history plasticity and population regulation in sea otters. Oikos 90(3): 457-468

Paddack, M.J. and J.A. Estes. 2000. Kelp forest fish populations in marine reserves and adjacent exploited areas of central California. Ecological Applications 1(3): 855

Watt, J., D.B. Siniff, and J.A. Estes. 2000. Inter-decadal patterns of population and dietary change in sea ottera at AMchitka Island, Alaska. Oecologia 124(2): 289

Dodson, Andy, Katherine Ralls, Mercedes Foster, Michael E. Soulé, Daniel Simberloff, Dan Doak, James A. Estes, L. Scott Mills, David Mattson, Rodolfo Dirzo, Héctor Arita, Sadie Ryan, Elliott A. Norse, Reed F. Noss and David Johns. 1999. Connectivity: maintaining flows in fragmented landscapes. In: Continental Conservation: Scientific Foundations of Regional Reserve Networks (Michael E. Soulé and John Terborgh, eds eds.). Island Press, Washington, DC

Terborgh, J., J.A. Estes and R. Noss. 1999. The role of top carnivores in regulating terrestrial ecosystems. Wild Earth 9(2): 42

Estes, J.A. 1998. Concerns about the rehabilitation of oiled wildlife. Conservation Biology 12:1156-1157

Estes, J.A., M.T. Tinker, T.M Williams, and D.F. Doak. 1998. Killer whale predation on sea otters linking coastal with oceanic ecosystems. Science 282:473-476

Scott, Michael J., Elliott A. Norse, Héctor Arita, Andy Dodson, James A. Estes, Mercedes Foster, Barrie Gilbert, Deborah Jensen, Richard B. Knight, David L. Mattson and Michael E. Soulé. 1998. The issue of scale in selecting and designing biological reserves. In: Continental Conservation: Scientific Foundations of Regional Reserve Networks (Michael E. Soulé and John Terborgh, eds eds.). Island Press, Washington, DC, p. 19-37

Estes, J.A., and D.O. Duggins. 1995. Sea otters and kelp forests in Alaska: generality and variation in a community ecological paradigm. Ecological Monographs 65:75-100

Steinberg, P.D., J.A. Estes, and F.C. Winter. 1995. Evolutionary consequences of food chain length in kelp forest communities. Proceedings of the National. Academy of Sciences 92:8145-8148

Estes, J.A. 1990. Growth and equilibrium in sea otter populations. J. Animal Ecol. 59:385-400

Duggins, D.O., C.A. Simenstad, and J.A. Estes. 1989. Magnification of secondary production by kelp detritus in coastal marine ecosystems. Science 245:170-173

Estes, J.A., D.O. Duggins, and G. Rathbun. 1989. The ecology of extinctions in kelp forest communities. Conservation Biology 3:252-264

Estes, J.A., and P.D. Steinberg. 1988. Predation, herbivory, and kelp evolution. Paleobiology 14:19-36

Iorns, D.B., R.G. Anthony, and J.A. Estes. 1986. Foraging strategies of Galucous-winged Gulls in rocky intertiday communities. Ecology 67:1460-1474

Estes, J.A., R.J. Jameson, and E.B. Rhode. 1982. Activity and prey selection in the sea otter: influence of population status on community structure. Am. Nat. 120:242

Estes, J.A., N.S. Smith, and J.F. Palmisano. 1978. Sea otter predation and community organization in the western Aleutian Island, Alaska. Ecology 59:822-833

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