Study shows ancient Alaskans were freshwater fishers

The research offers a glimpse at how early humans used a changing landscape and could offer insight for modern people facing similar changes.

"We are looking at humans as ecologists do, as biologists do," said Ben Potter, a UAF anthropology professor and co-lead author of the paper. "Even very early on, they are able to adapt to changing conditions."

The study, published recently in the journal Science Advances, shows that people living between 13,000 and 11,500 years ago in what is now Interior Alaska relied on freshwater fish like burbot, whitefish and pike for food. The study builds on earlier UAF findings that documented salmon fishing by the same population of ancient humans.

"That discovery was really surprising because it was far from the ocean, in an area near the edge of salmon habitat," said Potter. "That started us thinking: This could be a whole other angle on human ecology beyond large mammal hunting."

This new study began with a comprehensive review of all Interior Alaska archaeological sites 7,000 years old and older. The scientists found fish bones at seven sites. The team of archaeologists, anthropologists and fisheries biologists analyzed the bones to determine their age and species.

The bones were found inside homes and hearths and tended to be associated with base camps, rather than short-term hunting camps. They also were far from lakes and streams, so it's unlikely that predators moved them. The absence of fishhooks or spears at the sites suggests that the early Alaskans likely used nets and perhaps weirs to harvest the fish.

"This is a compelling, evidence-based case for freshwater fishing at the end of the last Ice Age," Potter said.

Recent large-scale excavations of residential base camps in the Tanana River basin have offered scientists a new opportunity to study early human populations in the region, he said. "This is a first in the Americas because, up until the last few decades, we haven't had fish remains clearly associated with human activities in these very early sites."

Scientists have documented humans in Alaska as far back as about 14,000 years ago. The heaviest use of freshwater fish by those early Alaskans appears to be between 13,000 and 11,500 years ago during the Younger Dryas, a period with cold and dry conditions in the midst of an overall warming trend at the end of the last ice age.

Until the beginning of the Younger Dryas, people relied more on waterfowl to augment large game like bison and elk. When temperatures started dropping around 13,000 years ago, that changed. Bones found at archaeological sites indicate they began to exploit multiple species of freshwater fish.

"While we don't know why the use of waterfowl diminished, we know that the climate was changing," Potter said. "One of the ways the people were able to adapt is to incorporate these new species and new technologies. Burbot, in particular, can be caught in late winter and early spring, when food resources were most scarce."

The solid tie to modern subsistence activities is also compelling, he said.

"There are millennia and millennia of fish use that continues into the modern day. Indigenous people's ancestors thousands of years ago were using the same resources. That has meaning to people today',' he said.

Other authors of the paper include co-lead author Carrin Halffman, and co-authors Holly McKinney, Josh Reuther and Charles Holmes, all of the UAF Department of Anthropology; Bruce Finney of Idaho State University; François Lanoë of the University of Arizona; J. Andrés López of the UAF College of Fisheries and Ocean Sciences; Erica Palmer, Marie Capps and Brian Kemp, all of the Laboratories of Molecular Anthropology and Microbiome Research at the University of Oklahoma. Reuther, Lanoë and Lopez are also affiliated with the University of Alaska Museum of the North.