Rockfish (Sebastes spp.) populations in the Salish Sea are at historically low levels due to slow population growth rates and a history of overexploitation. Fisheries managers are now attempting to rebuild stocks with a complete fishery closure. Food web models of the Salish Sea depend on current diet data, but lethal methods of diet sampling are not tenable with at-risk rockfish populations. Non-lethal sampling of diets, such as by gastric lavage, had not been attempted with rockfish, but can help minimize depletion of the populations for research needs. The objective of this study was to improve copper rockfish (S. caurinus) diet data in the San Juan Archipelago, using a non-lethal method of gut contents extraction. We used lavage to sample the diet of copper rockfish in San Juan Channel, WA, in fall 2010. Copper rockfish fed primarily on caridean shrimps and other demersal crustaceans, and consumed very few teleost prey. Previous studies of copper rockfish diet documented much higher reliance on teleost and non-shrimp crustacean prey. This difference in diets may be due in part to differing resource availability.