PubTalk 9/2007 — A Tale of Two Kelp Forests

Sea Otters and Ecosystem Dynamics in the Aleutians and the Commander Islands

By Tim Tinker, Research Biologist, University of California, Santa Cruz 

Sea otter populations in the central and western Aleutian Islands have declined by 75-95% over the past 15-20 years, while populations in the nearby Russian Commander Islands have remained roughly stable. There are no obvious environmental explanations for these disparate patterns, as the archipelagos are physically and biologically quite similar. Because of the differing population trajectories and the role of sea otters as keystone predators, the two kelp forest ecosystems that were once very similar are now quite different. What has caused these differences?