It's always been a given that Native Alaskans have been fishing for thousands of years, but now a new study concludes the practice dates all the way back to the Ice Age.
A study published this week in the Proceedings of the National Academy of Sciences found the earliest known evidence Ice Age humans in North America used salmon as a food source. Ancient DNA and stable isotope analysis from salmon vertebrae bones found in Interior Alaska indicate sea-run chum salmon were consumed by North American hunters 11,500 years ago.
The study notes that the findings are significant because it shows that Ice Age Paleoindians also fished, altering the understanding that the group was focused primarily on hunting big game. The study also notes that the findings at the Upward Sun River site -- approximately 1,400 kilometers upriver from the coast -- show chum salmon spawning runs were established by the end of the last Ice Age.
"There's such economic and cultural importance (of salmon) to Native Alaskans and Native Americans," said Carrin Halffman, UAF biological anthropologist and lead author of the study. "To find out that salmon fishing has such deep roots in Alaska and North America is very significant."
Dr. Ben Potter, UAF professor of anthropology and project director at the Upward Sun River site, said the findings also have broader implications toward understanding the technology, economy and settlement patterns of early Alaskans.
He said the salmon, with their large, annual runs, likely played into how early humans collected the resource and shaped their life patterns.
"It's a very predictable resource, versus going after caribou, which is not quite as predictable," Potter said.
The bones were found in a hearth at the Upward Sun River site near the Tanana River located east of Fairbanks. The same site is the location of the oldest human remains ever found in the North American Arctic and subarctic.
The remains, discovered in 2013, date back 11,500 years. Potter said the salmon vertebrae and human remains are contemporaneous.
Potter said fish remains are rarely found in early deposits since the bones are fragile and tend to deteriorate. Potter said because of that they're often underrepresented in the record.
But he said at the Upward Sun River site, the bones were backfilled into the hearth, leading to less exposure.
Halffman said the oldest known human Pacific salmon use in North America dates back to 6,000 to 7,000 years ago. She said in Alaska, human salmon use on the coast dates back 7,000 years.
While the Upward Sun River site site dates salmon fishing 11,500 years ago, Halffman said it's possible salmon fishing in Alaska goes back even further. The earliest known Alaska inhabitants date back as far as 14,000 years.
She said while there's no direct evidence supporting such a theory, in Interior Alaska there were no significant barriers -- such as ice blocking rivers -- that would have blocked salmon from migrating during that time period.
Potter said the new data point leads to further questions about how people and salmon adapted while the climate was changing at the end of the last Ice Age. He said that information, which is not yet known, could be useful for modern salmon management purposes.