The Kelp Highway Hypothesis: Marine Ecology, the Coastal Migration Theory, and the Peopling of the Americas

ABSTRACT In this article, a collaborative effort between archaeologists and marine ecologists, we discuss the role kelp forest ecosystems may have played in facilitating the movement of maritime peoples from Asia to the Americas near the end of the Pleistocene. Growing in cool nearshore waters along rocky coastlines, kelp forests offer some of the most productive habitats on earth, with high primary productivity, magnified secondary productivity, and three-dimensional habitat supporting a diverse array of marine organisms. Today, extensive kelp forests are found around the North Pacific from Japan to Baja California. After a break in the tropics—where nearshore mangrove forests and coral reefs are highly productive—kelp forests are also found along the Andean Coast of South America. These Pacific Rim kelp forests support or shelter a wealth of shellfish, fish, marine mammals, seabirds, and seaweeds, resources heavily used historically by coastal peoples. By about 16,000 years ago, the North Pacific Coast offered a linear migration route, essentially unobstructed and entirely at sea level, from northeast Asia into the Americas. Recent reconstructions suggest that rising sea levels early in the postglacial created a highly convoluted and island-rich coast along Beringia's southern shore, conditions highly favorable to maritime hunter-gatherers. Along with the terrestrial resources available in adjacent landscapes, kelp forests and other nearshore habitats sheltered similar suites of food resources that required minimal adaptive adjustments for migrating coastal peoples. With reduced wave energy, holdfasts for boats, and productive fishing, these linear kelp forest ecosystems may have provided a kind of "kelp highway" for early maritime peoples colonizing the New World. Keywords: archaeologymarine ecologykelp forestsmaritime migrationsPacific Rim ACKNOWLEDGEMENTS Inspiration for the "Kelp Highway Hypothesis" emerged during kelp forest working group meetings associated with the Long-Term Ecological Records of Marine Environments, Populations, and Communities Working Group, supported by the National Center for Ecological Analysis and Synthesis and chaired by Jeremy Jackson. Our work was supported by the National Science Foundation (Grant# DEB-0072909), the University of California, and our home institutions. We are indebted to Mark Clementz, Michael Collins, Paul Dayton, Jeremy Jackson, Brian Kinlan, Kent Lightfoot, Patricia Netherly, and an anonymous reviewer for their helpful comments. Finally, we thank Scott Fitzpatrick, Christine Armstrong, and the editorial staff of JICA for help in the revision and production of this article.