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5,000 year old Indigenous fisheries data show impact of warming climate

June 01, 2022

credit: Dylan Hillis

A new study--using historical fisheries data from two Indigenous archaeological sites on the BC west coast--show the impact of a warming climate on fish types.

Fish fragments unearthed from the villages of Ts’ishaa and Huu7ii in Barkley Sound, B.C., are the focus of the recent study, in an effort to better understand how ocean temperatures changed between 3000 B.C. to about 1700 A.D.

Researchers from the University of Victoria (UVic), UBC’s Institute for the Oceans and Fisheries (IOF), and  Simon Fraser University (SFU) in collaboration with the Huu-ay-aht and Tseshaht First Nations converted counts of fish bones into fish weights, and then into ocean temperature.

“We estimate that the temperature of the catch rose about 0.3 to 0.7 degrees Celsius over this time period,” said UVic anthropology master’s student and lead author Dylan Hillis.

"Over this large period of time, there’s more or less the same species of fish being represented, but in different proportions. Salmon made up the bulk and become even more common later in time but warmer-water species like sculpin, hake, and dogfish also increased. This change in the relative amount of what fish were caught was enough to detect changes in temperature,” adds Hillis.

“Intensifying marine heat waves will profoundly affect our coastal oceans and the food they can produce,” said SFU co-author Dr. Anne Salomon. “Looking back through time over five millennia not only improves our baseline to assess change, it offers a window into how humans adapted to change and can help guide what resilient human-ocean relationships could look like in the future.”

“There are Indigenous heritage sites everywhere on the BC coast that hold valuable historical data that pre-dates records kept by settlers,” says McKechnie. “This creates additional opportunities for First Nations to weigh in on marine planning, climate adaptation and fisheries management.”

“I hope the archaeological findings are used to educate our people about how their ancestors lived,” said Tom Happynook, Hereditary Whaling Chief of the Huu-ay-aht First Nations.

“I also hope that the information is shared with the public at large, including scholars on climate change, so they can have an understanding of our world views… we were an organized society with Hereditary Chiefs who held responsibilities and obligations for the lands, resources and waters which our people relied on to sustain our Nation for such a long time,” adds Happynook.

Ken Watts, elected Chief Councillor of Tseshaht First Nation, echoed these sentiments.

“We benefit from knowing our water temperatures have changed in the past,” says Watts.

“This study can show we adapted, and it now teaches us that we need to plan to adapt again as our world is evolving daily; we hope this will influence our discussions with government, but more importantly, ensure we leave our children and future generations with a better world than that which we live in now,” adds Watts.

The study “A palaeothermometer of ancient Indigenous fisheries reveals increases in mean temperature of the catch over five millennia” was published in the journal Environmental Biology of Fishes.