Feeding preferences and the effect of temperature on feeding rates of the graceful kelp crab, .

Graceful kelp crabs () are abundant consumers in shallow subtidal ecosystems of the Salish Sea. These dynamic habitats are currently experiencing multiple changes including invasion by non-native seaweeds and ocean warming. However, little is known about foraging ecology, therefore we investigated their feeding preferences between native and invasive food sources, as well as feeding rates at elevated temperatures to better assess their role in changing coastal food webs. To quantify crab feeding preferences, we collected from San Juan Island, WA and conducted no-choice and choice experiments with two food sources: the native kelp, and the invasive seaweed, . In no-choice experiments, ate equal amounts of and . However, in choice experiments, preferred over . To test effects of temperature on these feeding rates, we exposed to ambient (11.5 ± 1.3 °C) or elevated (19.5 ± 1.8 °C) temperature treatments and measured consumption of the preferred food type, Crabs exposed to elevated temperatures ate significantly more than those in the ambient treatment. Our study demonstrates the diet flexibility of , suggesting they may be able to exploit increasing populations of invasive in the Salish Sea Warming ocean temperatures may also prompt to increase feeding, exacerbating harmful impacts on which is already vulnerable to warming and invasive competitors.