Marine Biology

, Volume 159, Issue 12, pp 2641–2649

Interactions among sea otters, sea stars, and suspension-feeding invertebrates in the western Aleutian archipelago

Original Paper

DOI: 10.1007/s00227-012-2021-7

Cite this article as:
Vicknair, K. & Estes, J.A. Mar Biol (2012) 159: 2641. doi:10.1007/s00227-012-2021-7


The structuring and organizing effects of apex predators on ecosystems are becoming increasingly well documented. The enhancement of kelp forests via sea otter predation on herbivorous sea urchins is among the earliest and best known examples. This study provides evidence for direct and indirect trophic interactions among sea otters, predatory sea stars, and filter-feeding mussels (Mytilus trossulus) and barnacles (Semibalanus cariosis). In western Massacre Bay at Attu Island (173°E, 53°N), subtidal transects showed sea star body size and biomass density declined markedly between 1983 and 1994 as sea otters reinhabited this area. Mussels and barnacles translocated from the rocky intertidal zone to shallow subtidal habitats to assess loss rates from sea star predation showed lower mortality rates after the arrival of sea otters. Prey mortality rates in subtidal caged controls were consistently low and similar to those of intertidal controls in both years. These findings elucidate a trophic pathway by which sea otters can influence ecosystems separate from the well-known sea otter/sea urchin/macroalgae cascade.

Supplementary material

227_2012_2021_MOESM1_ESM.docx (45 kb)
Supplementary material 1 (DOCX 44 kb)
227_2012_2021_MOESM2_ESM.docx (42 kb)
Supplementary material 2 (DOCX 41 kb)

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  1. 1.Institute of Marine ScienceUniversity of CaliforniaSanta CruzUSA
  2. 2.Department of Ecology and Evolutionary BiologyUniversity of CaliforniaSanta CruzUSA

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