Taylor Vollman

Topic

Ancient abundance, distribution, and size of Olympia Oysters (Ostrea lurida) in the Salish Sea: a perspective from the Lekwungen village of Kosapsom (DcRu-4), southern Vancouver Island, British Columbia

Department of Anthropology

Date & location

• Friday, January 19, 2024

• 11:00 A.M.

• Clearihue Building, Room B007

• And Virtual Defence

Reviewers

Supervisory Committee

• Dr. Iain McKechnie, Department of Anthropology, University of Victoria (Supervisor)

• Dr. Marco Hatch, Huxley College of Environment, Western Washington University (Non-Unit Member) 

External Examiner

• Dr. Loren Elizabeth McClenachan, School of Environmental Studies, University of Victoria

Chair of Oral Examination

• Dr. Rachel Cleves, Department of History, UVic

   

Abstract

Olympia oysters (Ostrea lurida) are the only oyster species native to the Northwest Coast of North America and are currently a focus of restoration and management following a collapse over the past 150 years. This thesis examines 42 archaeological assemblages containing Olympia oysters in the Salish Sea to better understand Indigenous uses, changes in abundance and distribution between ancient and modern and develops a method to estimate ancient size-at-harvest from partial valves. I observe that Olympia oysters are not a particularly abundant species in archaeological sites when measured by weight and MNI (<15% relative frequency) except in a few sites with high abundance in specific nearshore habitats and locations. Additionally, I examine the size and abundance of Olympia oysters from the Kosapsom Village site (DcRu-4), a site with exceptionally high Olympia oyster frequency (~68 % MNI) located on Southern Vancouver Island in British Columbia in the traditional territories of Esquimalt and Songhees Nations. I compare oyster size ranges from Kosapsom to modern restoration sites and observe that sizes are larger than modern oysters in the same waterway but are the same size as a larger restoration site in Fidalgo Bay, Washington. Both abundance and size at Kosapsom increased over 1800 years. I interpret these increased sizes (~14% increase) as reflective of harvesting restrictions and population enhancement strategies, which are consistent with maintaining long-term harvest stability. This research contributes to the growing recognition that archaeological records of traditional Indigenous shellfish use and management hold great potential to expand historical baselines and inform modern coastal restoration and conservation strategies.