For much of the 20th century, the Coastal Migration Theory, which proposed that some of the First Americans colonized the New World by following North Pacific coastlines from Asia into the Americas, was considered highly unlikely by most archaeologists. Theories about how and when people first settled the Americas were dominated by terrestrial models proposing that Upper Paleolithic hunters followed big game herds from Siberia to Beringia and down a long, narrow “ice-free” corridor that opened as the vast Laurentide and Cordilleran ice sheets began to retreat. These hunters, long thought to be Clovis people, focused on hunting large land mammals (mammoths and mastodons, etc.), spreading into coastal areas only after game herds were depleted in the interior. Once they reached the coast, Clovis descendants were seen as gradually adjusting to life by the sea in a process that spanned millennia.

Laurentide Ice SheetLaurentide Ice Sheet at Deglacial

Today, the Coastal Migration Theory has gone from marginal to mainstream as evidence for early fishing and seafaring has accumulated around the Pacific Rim and the rest of the world. It is now known that Island Southeast Asia, Australia, western Melanesia, and the Ryukyu Islands were settled by seafaring peoples between ~50,000 and 35,000 years ago, and California’s Channel Islands were settled at least 13,000 years ago. The tide also turned with the identification of several types of seaweed at the Monte Verde II site near the coast of Chile, dated to ~14,000 years ago. Recent geological research suggests that the ice-free corridor was still closed at that time, while the coastal route appears to have been open by ~16,000 years ago.

Erlandson et al. (2007) proposed an ecological correlate to the Coastal Migration Theory, the Kelp Highway Hypothesis, suggesting that kelp forests and other North Pacific coastal ecosystems may have facilitated the peopling of the Americas after the end of the Last Glacial. They noted that extensive and highly productive kelp forests from Japan to Baja California supported similar marine organisms: sea otters and other marine mammals, abalones, urchins, and other shellfish; numerous fish and seabirds; seaweeds and more. As the world warmed after 17,000 years ago, and Cordilleran ice retreated from the coastlines of northwestern North America, seafaring peoples could have traversed the Pacific Rim relatively rapidly, following a coastal route entirely at sea level, without major obstructions, and offering a diverse array of terrestrial and marine resources.

Identifying early coastal sites is challenging given the effects of post-glacial sea level rise and landscape changes along North Pacific coastlines. However, there are tantalizing hints from genetics, early human skeletons, and Late Pleistocene technological assemblages that may support the Coastal Migration Theory and Kelp Highway Hypothesis. This includes broadly similar stemmed (or tanged) projectile points found around the Pacific Rim from Japan and Northeast Asia, to the Pacific Northwest and California’s Channel Islands, and South America. Paleocoastal Research Project team members are actively engaged in studying the possible maritime origins of the First Americans.