Featuring an ethnohistory of two Coast Salish communities — the Suquamish Tribe in Washington State and the W̱SÁNEĆ Nation in British Columbia — this dissertation is a transborder study of Indigenous shellfish harvesting and foreshore rights in the Salish Sea across the twentieth century. It explores the history of the interface between land and sea within the context of treaty rights to resources and Indigenous nations’ sovereignty over marine habitats. This study also turns the ethnographic lens on the settler population. Using tools offered by recent scholarship on settler colonialism, it helps explain why the general public has resisted treaty and Aboriginal rights to fisheries and other resources. This dissertation also reveals Coast Salish nations’ responses to settler encroachment of their foreshores and state disruption of their management of the marine environment throughout the twentieth century and offers two community studies to illustrate how local Indigenous communities have re-shaped relationships between Indigenous peoples and settlers on the Salish Sea. The first study examines Suquamish’s right to shellfish under the Point Elliott Treaty and affirmed by the 1994 Rafeedie decision, as well as the interrelated 1980s tidelands case for ownership of the beaches attached to the Port Madison Reservation. The second examines W̱SÁNEĆ people’s defense of Saanichton Bay from a marina development, when the SȾÁ,UTW̱ (Tsawout) community wielded its Douglas Treaty rights in Claxton v. Saanichton Marina, 1987. Utilising Karl Jacoby’s concept of a “moral ecology,” this study argues that by ignoring Indigenous Knowledge regarding marine resource management, and by creating an overly complex regulatory scheme guided by principles of capitalism, settler officials on both sides of the border missed opportunities to avoid some of the greatest challenges to marine health and resource survival in the Salish Sea. / Graduate / 2023-04-12