The Kelp Highway hypothesis — formally proposed by archaeologist Jon Erlandson and colleagues — put ecological flesh on this geographical argument.

The Pacific Rim kelp forests, which stretch from northeast Asia down through the Aleutians and Alaska and along the North American coast to Baja California, form a relatively continuous ecological zone of high biological productivity.

Marine mammals, fish, shellfish, and seabirds concentrated in kelp forests provide a rich and predictable food base.

A maritime people skilled in exploiting kelp-forest resources could, in principle, move along this coast from northeast Asia toward the Americas while living off the sea’s produce along the way.

In this context, the Arlington Springs individual’s presence on an island off the California coast approximately 13,000 years ago was exactly what a Kelp Highway migration would predict: people already skilled in maritime movement, already comfortable crossing open water, already harvesting marine resources, already established along the California coast at the close of the Ice Age.