This paper reports results of test excavations conducted at BjCo-02, a shell midden on the Mi'kmaw island of Maligomish located off the southern coast of the Northumberland Strait in northeastern Nova Scotia. While the site yielded few artifacts, preliminary observations indicate changes in the proportions of the two dominant shellfish species (eastern oyster and soft-shell clam) between 1500 and 500 y.b.p. The appearance of eastern oyster at ca. 1500 y.b.p. and its virtual absence ca. 500 y.b.p. suggest that the Maligomish midden conforms and, at the same time, challenges previously observed patterns at other shell midden sites in the Maritime Provinces of Canada and along the east coast of the United States. Drawing on the preliminary archaeological data from BjCo-02, and previous palynological studies from the region, this paper argues for the recognition of Northumberland Strait as a unique environment within the broader northeastern North American region. The paper also makes recommendations for future research to confirm the apparent species shift, including the proper calibration of radiocarbon dates to account for marine reservoir effects.