March 2025

Sustainable ancestral fisheries across millennia

Vancouver is currently the major city across the Canadian Pacific coast, and the third biggest urban area in Canada after Toronto and Montreal. Located along the Burrard Peninsula, it lies between the Burrard Inlet and Frasier River, isolated from the Pacific Ocean by the Vancouver Island. This environment creates a privileged ecosystem that has been exploited for millennia by human settlements [1], first by Native ancestral cultures with recorded archaeological evidence dating back several thousand years, followed by European exploration during the late XVIII and early XIX centuries, and subsequent colonial urbanization during the late XIX century leading to a quick growth and industrial development. With about than 2.5 million inhabitants in its metropolitan area, it is currently one of the busiest port cities in North America, comprising a melting pot of diverse cultures and ethnicities, and a leading multibillion economy based on Port trades, forestry and mining activities, but also with an active development in software, biotechnology and aerospace industries. As a modern developed and vibrant cosmopolitan area, human urbanism and economic activities have made a huge impact in the surrounding ecosystem, with the loss of multiple local habitats and animal and plant populations that once thrived in the region. Back before European colonization, the scenery was radically different: What is now known as the Burrard Inlet was then called səlilwət, a territory of the Tsleil-Waututh community, and Indigenous Coast Salish culture that settled and lived along those inlet coastlines for millennia [1,2]. Central to the Tsleil-Waututh society was the fishing and harvesting of shellfish, as a way of sustaining a diet comprising salmon, herring, waterfowl, and clams, with berries, plant foods, fruits, deer, ling cod, anchovy, eulachon, and halibut, among others. From these, salmon consumption and its transformation for long storage was a key resource, with an estimate of around 300-350 kg consumed per person per year, thus allowing permanent settlements year-round.  

Tsleil-Waututh Nation and chum salmons (top two) compared to pink salmon (bottom). Pictures provided by BillB200 & Vineyard under CC-BY-SA.

 

One of the most prominent archaeological sites studied so far is known as təmtəmíxʷtən, a large settlement located centrally within the Tsleil-Waut territory in the final intersection of the Burrard Inlet around the Indian arm, a privileged spot for accessing salmon and other fisheries. Dr. Jesse Morin has been investigating the archeological evidence of this ancient human settlement and they ways that Tsleil-Waututh managed the ecosystem for ensuring a stable and sustainable food supply based on fishing and harvesting.  

Ancient DNA analysis of salmon bones found in the site allowed the identification of the most consumed species by Tsleil-Waututh people [3]. Contrary to current predominance of sockeye salmon in the area (O. nerka), researchers found that chum salmon (O. keta) was the main species found across all sites and time periods analyzed, with sporadic findings of sockeye (probably transplanted from Fraser River), pink (O. gorbuscha), coho (O. kisutch) and Chinook (O. tshawytscha) salmons. The prevalence of chum over other species in the archeological record of the area is explained, according to the authors, by the reliance on late varieties of salmon ascending the inlet in the fall or early winter, so that Indigenous people would preferentially harvest them for preservation and later consumption. This would imply at least a fall/winter occupation of the site, whereby captured salmons would be smoked and/or dried, something that correlates with ethnographical records [2]. Summer species present in the site like sockeye, pink or Chinook salmons, as well as Spring spawning herring and eulachon, the two later ones sometimes even more prevalent than salmons, also justify a spring/summer occupation of the area. Therefore, rather than winter sites used for hunting and fishing, these sites would represent permanent settlements of Tsleil-Waututh people, from which some groups would periodically relocate while others would remain all year-round.  

Another interesting finding was the strong male-sex bias found for chum salmon remains [4] as evidence of selective harvesting of males for consumption, where few males left to reproduce would fertilize a greater pool of females, contributing to maintain future stocks of salmon in the inlet. However, this finding was not reproduced in all sites analyzed, even if they were located quite proximally to each other. The explanation of this apparent but inconsistent sex bias in consumed salmons is, according to the authors, based on greater size and meat availability provided by males, but also on ensuring a sustainable fishing practice. Nevertheless, this finding seems dependent on access/stewardship to a weir at the Indian River that was closely and carefully managed, while other communities harvested fish less discriminately from smaller creeks, streams, and the saltwater.  

Contrary to post-contact and industrial practices, Indigenous ancestral fisheries seem to have been sustainable over millennia, with an uninterrupted archaeological record that justifies the presence of permanent human settlements that managed salmon populations to ensure future food stocks without impacting ecosystemic equilibriums. Despite modern developments that have greatly modified the Burrard Inlet area and the species living within, the Tsleil-Waututh Nation and their ancestral practices are well positioned to contribute towards a sustainable salmon fishery once again.

 

References

1. Morin, J. Tsleil-Waututh Nation’s History, Culture and Aboriginal Interests in Eastern Burrard Inlet. Report on file, Gowlings, Lafleur, Henderson LLP, Vancouver (2015).
2. Efford, M. et al. Archaeology demonstrates sustainable ancestral Coast Salish salmon stewardship over thousands of years. PLoS One 18, e0289797 (2023).
3. Morin, J. et al. DNA-based species identification of ancient salmonid remains provides new insight into pre-contact Coast Salish salmon fisheries in Burrard Inlet, British Columbia, Canada. J Archaeol Sci Rep 37, 102956 (2021).
4. Morin, J. et al. Indigenous sex-selective salmon harvesting demonstrates pre-contact marine resource management in Burrard Inlet, British Columbia, Canada. Sci Rep 11, 21160 (2021).

 

Below, Jesse shared with us further details about his profile, career, prospects and future projects:  

1. Briefly introduce yourself. What is your origin story for how you got into science?
I actually started in hard science and started archaeology to get out of it. But, then it became apparent that scientific tools are really the core of a lot of archaeological investigations, so I began to collaborate more with geneticists and chemists to address archaeological research issues.  

2. How and/or why did you start working on this project?
I had designed this project around 2017 as a way of addressing both past Tsleil-Waututh subsistence and the pre-contact ecology of Burrard Inlet. We obtained funding for the work in 2019 and got started, and published our results in 2021.  

3. Were there any major challenges in this project? How did you overcome them?
Funding was the limitation for the work.  

4. What do you think are the main take-home messages of this project?
Demonstration of the long-term success of Indigenous resource stewardship.  

5. What do you think is missing in the field that you would like to work on?
More samples from more sites/regions, and population genetics of the salmon species of interest to explore abundance through time.  

6. Where do you see yourself in the near future?
Addressing the issue above, and undertaking a parallel project on Vancouver Island.