ORIGINAL PAPER Regional ecological variability and impact of the maritime fur trade on nearshore ecosystems in southern Haida Gwaii (British Columbia, Canada): evidence from stable isotope analysis of rockfish (Sebastes spp.) bone collagen Paul Szpak & Trevor J. Orchard & Anne K. Salomon & Darren R. Gröcke Received: 27 July 2012 / Accepted: 17 January 2013 # Springer-Verlag Berlin Heidelberg 2013 Abstract The maritime fur trade (1785–1840s) led to the local extinction of sea otters (Enhydra lutris) in many parts of the northeast Pacific. On the basis of studies of extant sea otter populations, it has been established that they have a disproportionate effect on nearshore ecosystems by limiting sea urchin abundance and facilitating the establishment of nearshore kelp forests; in the absence of sea otters, a local reduction in kelp-derived carbon is therefore expected. We measured the isotopic composition (δ 13 C and δ 15 N) of rock- fish (Sebastes spp.) bone collagen from late Holocene ar- chaeological sites in southern Haida Gwaii, BC, Canada, using δ 13 C as a proxy for kelp-derived carbon in the diet and δ 15 N as a proxy for trophic position. We observed signifi- cant spatial variability in rockfish kelp-derived carbon (δ 13 C), but not trophic level (δ 15 N). Kelp-derived carbon varied largely as a function of site characteristics (wave exposure), suggesting that local oceanographic conditions are important factors with respect to consumer tissue isoto- pic compositions. Kelp-derived carbon decreased in post- European contact rockfish relative to pre-European contact rockfish, likely as a result of the reduction of kelp forests associated with the local extirpation of sea otters. Although we detected a reduction in kelp-derived carbon in rockfish diets, we found no shift in trophic level at sites occupied following the maritime fur trade. This implies a shift in local ecosystems, and particularly in carbon sources, following the maritime fur trade, likely due to a trophic cascade resulting from the local extirpation of sea otters. Stability in rockfish trophic levels, however, implies that rockfish continued to feed at similar trophic levels, consuming prey with similar nitrogen isotopic compositions. Keywords Maritime fur trade . Tropic cascade . Stable isotopes . Historical ecology . Sea otter (Enhydra lutris) . Northwest coast Introduction The Pacific maritime fur trade, which peaked in the early part of the nineteenth century, was a time of massive change, in both social and ecological terms. The commercial mari- time fur trade began in earnest with a surge in British presence between 1780 and 1800, followed by a period of American dominance with a large number of ships out of New England until the 1840s (Gibson 1988). By this time, fur-bearing marine mammal populations had markedly de- clined and there was a complete shift in the nature of the fur trade, which then became dominated by the Hudson’ s Bay Company and focused on terrestrial furs (Wolf 1982). During the height of the Pacific maritime fur trade (1785–1825), the most sought after species was the sea otter (Enhydra lutris). One result of the fur trade was a massive decline in sea otter populations, possibly in excess of 99 % (Kenyon 1969; Riedman and Estes 1990), with otters P. Szpak (*) Department of Anthropology, The University of Western Ontario, London, ON, Canada e-mail: pszpak@uwo.ca T. J. Orchard Department of Interdisciplinary Studies, Lakehead University Orillia, Orillia, ON, Canada A. K. Salomon School of Resource and Environmental Management, Simon Fraser University, Burnaby, BC, Canada D. R. Gröcke Department of Earth Sciences, Durham University, Durham, UK Archaeol Anthropol Sci DOI 10.1007/s12520-013-0122-y