Killer whale predation on sea otters linking oceanic and nearshore ecosystems

  title={Killer whale predation on sea otters linking oceanic and nearshore ecosystems},
  author={Estes and Tinker and Williams and Doak},
  volume={282 5388},
  • EstesTinker Doak
  • Published 16 October 1998
  • Environmental Science
  • Science
After nearly a century of recovery from overhunting, sea otter populations are in abrupt decline over large areas of western Alaska. Increased killer whale predation is the likely cause of these declines. Elevated sea urchin density and the consequent deforestation of kelp beds in the nearshore community demonstrate that the otter's keystone role has been reduced or eliminated. This chain of interactions was probably initiated by anthropogenic changes in the offshore oceanic ecosystem. 

The rise of an apex predator following deglaciation

Sea otters (Enhydra lutris) are an apex predator of the nearshore marine community and nearly went extinct at the turn of the 20th century. Reintroductions and legal protection allowed sea otters to

Effects of Apex Consumers Cascade Dynamically across Trophic Levels

Simple ecosystems in the northern Pacific Ocean are particularly suitable to test the hypothesis. In 1970’s, communities at islands lacking sea otters were characterized by high density of sea

Causes and consequences of marine mammal population declines in southwest Alaska: a food-web perspective

Populations of sea otters, seals and sea lions have collapsed across much of southwest Alaska over the past several decades. The sea otter decline set off a trophic cascade in which the coastal

Effects Of Sea Otter Colonization On Soft-Sediment Intertidal Prey Assemblages In Glacier Bay, Alaska

The occurrence of top-down structuring in soft-sediment systems over a multi-decadal time scale was established and was consistent with findings in other habitats, where reduced densities and sizes of prey were documented.

Sequential megafaunal collapse in the North Pacific Ocean: An ongoing legacy of industrial whaling?

  • A. SpringerJ. Estes B. Pfister
  • Environmental Science
    Proceedings of the National Academy of Sciences of the United States of America
  • 2003
It is proposed that decimation of the great whales by post-World War II industrial whaling caused the great whale' foremost natural predators, killer whales, to begin feeding more intensively on the smaller marine mammals, thus “fishing-down” this element of the marine food web.

Cascading Effects of the Loss of Apex Predatory Sharks from a Coastal Ocean

Impacts of chronic overfishing are evident in population depletions worldwide, yet indirect ecosystem effects induced by predator removal from oceanic food webs remain unpredictable. As abundances of

Human Impacts on Seals, Sea Lions, and Sea Otters

Review of  Human Impacts on Seals, Sea Lions, and Sea Otters: Integrating Archaeology and Ecology of the Northeast Pacific .  Todd J. Braje and Torben C. Rick, editors. 2011. Univer sity of

Depletion of coastal predatory fish sub-stocks coincided with the largest sea urchin grazing event observed in the NE Atlantic

It is hypothesized that coastal predatory fish were important in regulating sea urchins, and that a local population dynamics perspective is necessary in management of coastal ecosystems.

Complex trophic interactions in kelp forest ecosystems

It is hypothesized that killer whales sequentially “fished down” pinniped and sea-otter populations after their earlier prey, the great whales, were decimated by commercial whaling.



Sea Otters: Their Role in Structuring Nearshore Communities

A comparison of western Aleutian Islands with and without sea otter populations shows that this species is important in determining littoral and sublittoral community structure and suggests that sea otters indirectly affects island fauna associated with macrophyte primary productivity.

The Community Ecology of Sea Otters

This book discusses effects of predation by sea otters in nearshore benthic communities of the North Pacific. It includes chapters written by researchers in kelp forest, rocky intertidal, and soft

Magnification of Secondary Production by Kelp Detritus in Coastal Marine Ecosystems

Stable carbon isotope analysis confirmed that kelp-derived carbon is found throughout the nearshore food web.

Sea Otters and Kelp Forests in Alaska: Generality and Variation in a Community Ecological Paradigm

Analysis of generality of a three-trophic-level cascade among sea otters, invertebrate herbivores, and macroalgae in Alaska demonstrates that sea otter predation has a predictable and broadly generalizable influence on the structure of Alaskan kelp forests.

Diet diversity of Steller sea lions (Eumetopias jubatus) and their population decline in Alaska: a potential relationship

The diet of Steller sea lions was examined during June-August 1990-1993 from six areas in the Aleutian Islands and Gulf of Alaska and related these diets to sea lion population growth.

Behavioral ecology of killer whales (Orcinus orca), in the Pacific Northwest

Killer whales (Orcinus orca) were found to use different physiographic regions of their habitat in unique ways, which most likely represent cultural mechanisms that have been learned through trial and error experiences leading to successful foraging strategies.

The Decline of the Steller Sea Lion in the Northeast Pacific: Demography, Harvest or Environment?

The results show that deterministic transient popu- lation behavior, historical pup harvesting, and short-term environmental stochasticity are unlikely causes for the decline of Steller sea lions in the North Pacific.

Effects of Fish in River Food Webs

  • M. Power
  • Environmental Science
  • 1990
Experimental manipulations of fish in a Northern California river during summer base flow reveal that they have large effects on predators, herbivores, and plants in river food webs, providing evidence that the Hairston, Smith, Slobodkin–Fretwell theory of trophic control has application to river communitics.

Evolutionary consequences of food chain length in kelp forest communities.

The findings suggest that top-level consumers, acting through food chains of various lengths, can strongly influence the ecology and evolution of plantherbivore interactions.

Killer whales : the natural history and genealogy of Orinus orca in British Columbia and Washington

Watching killer whales in the wild in British Columbia and Washington state has become a popular recreational activity in the last decade. Nothing quite matches the thrill of witnessing a pod of