Invasive species have detrimental effects on ecosystems around the world and are a driving factor behind the loss of biodiversity. Once established, many populations of invasive species are difficult to control or eradicate. Red Swamp Crayfish (Procambarus clarkii) is an extremely prolific invasive species that is established in more than 100 countries worldwide and is demonstrated to have negative effects on native ecosystems. Management of Red Swamp Crayfish is difficult and likely requires multiple approaches including biological control by fishes. However, little research exists to inform managers on which biological control agents are likely to be effective. Herein, I describe a foraging experiment to evaluate the predatory capacity of Largemouth Bass, Green Sunfish, and Bluegill Sunfish on Red Swamp Crayfish, all of which are likely biological control candidates. I used an optimal foraging framework to develop cost/benefit ratios based on crayfish size to determine the optimal range of crayfish sizes consumed by each predator species. I measured orientation, pursuit, and handling time to develop optimal foraging curves, while recording consumption of crayfish based on size, sex, and reproductive form. My results indicated that the optimal sizes of crayfish were 12-15mm CL for Bluegill, 17-22mm CL for Green Sunfish, and 20-40mm for Largemouth Bass. These results indicate that managers should consider supplementing existing predator populations with both Lepomis species and Largemouth Bass to ensure a broad range of crayfish are consumed.
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