If you are what you eat, then your compost pile is a treasure trove of information about your culture and surrounding environment. Archaeologists in the Pacific Northwest have spent the last 40 years picking through ancient settlements that contain animal bones, scraps, and other debris to find out what coastal people were eating thousands of years ago. But until now, no one had compiled it into a bigger picture.
“We know a lot more than we think we do about Indigenous fishing practices, but our knowledge was scattered across hundreds of individual project reports,” says Hakai archaeologist Iain McKechnie, an assistant professor at the University of Victoria.
McKechnie and coauthor Madonna Moss, a professor at the University of Oregon, pored over hundreds of reports and compiled the information into a new paper published in the scientific Journal of Archaeological Science: Reports. The pair catalogued over half a million fish bones that were excavated from 222 separate archaeological sites in the Pacific Northwest over the past 40 years—over 10,000 years of compost.
“When it comes to archaeology, examining geographic patterns can say a lot about cultural practices over time. These data offer a new way to consider the cultural similarities and distinctiveness of different Indigenous people on the coast with respect to fisheries,” says McKechnie.
McKechnie and Moss used a simple but seldom used quantitative measure called ubiquity—whether bones from a certain fish species were found at any given archaeological site—and mapped the resulting patterns across the Pacific Coast of North America. Ubiquity is like measuring the popularity of a YouTube video by how many countries people watch it in, as opposed to total number of views. Ubiquity doesn’t give a measure of how much of each fish species people used, but rather, where and how commonly they used it.
As expected, bones from the seven local salmon species showed they were among the most common fish used on the coast. However, salmon weren’t the only ubiquitous fish. Pacific herring, an oily fish that schools in huge numbers, was the single most common species found.
Until recently, archaeologists overlooked herring and many other small fish for one simple reason. Archaeologists use screens to sift through excavated material from a dig, like panning for osteological gold, where the majority of small fish bones would slip through the standard screen size. When smaller mesh sizes became commonplace, archaeologists suddenly started finding reams of tiny fish bones.
“This study affirms the importance of both herring and salmon and a host of other species in the diet and economy of Indigenous people,” says McKechnie.
But it wasn’t just herring and salmon on the menu. Halibut and lingcod were also fished thousands of years ago, as they are today, but other species that are often discarded or ignored by present-day fishers show up routinely in archaeological sites. Even McKechnie and Moss were surprised at how commonly they found fish like greenlings, Irish lords, surfperch, and smelts in archaeological sites.
“People were using a much wider range of species in the past. Many fish missing from today’s marine menu clearly served important roles for millennia. Sculpins, plate-sized flatfish, dogfish and rockfish were vitally important for peoples from Oregon up to Alaska,” says McKechnie.
The next step is to talk to First Nations about the significance of these archaeological patterns, including recipes and methods of capture, as well as to look closer at where different fish used to live, so that modern fisheries managers can compare to where these fish species live now. Other archaeological measures of fish bones can also be used to reconstruct how abundant certain fish were in the past, which is not often calculated for the periods prior to industrial fishing in the 20th century.
“Mapping these patterns allows us to synthesize information in ways we couldn’t have imagined 10 years ago. New analytical techniques make possible a much broader understanding of the diversity of fishing and fish use,” says Moss.
“These ancient settlements are an incredible archive of human use, as well as historical ecological conditions. A lot of these fish species are sentinels that can be used as proxies to gauge environmental conditions at that time,” says McKechnie.
It’s clear now that the fish diet of coastal people was broader and more complex than previously thought. Sculpin stew, anyone?
This research was supported by a Social Science and Humanities Research Council of Canada post-doctoral fellowship at the University of Oregon, Simon Fraser University, and the Tula Foundation.
McKechnie, I., and M.L. Moss. 2016. Meta-analysis in zooarchaeology expands perspectives on Indigenous fisheries of the Northwest Coast of North America. Journal of Archaeological Science: Reports doi:10.1016/j.jasrep.2016.04.006