IT’S A TRAP! AN EVALUATION OF 12 PASSIVE TRAP TYPES TO EFFECTIVELY CATCH AND CONTROL THE INVASIVE RED SWAMP CRAYFISH IN STREAMS OF THE SANTA MONICA MOUNTAINS
The invasive red swamp crayfish poses a significant threat to habitat quality and community diversity in streams systems of the Santa Monica Mountains. With no natural predators or competitors, crayfish can consume adult, juvenile and egg forms of native fish, amphibians, and benthic macroinvertebrates. Mountain Restoration Trust has managed crayfish populations in the Santa Monica Mountains for almost a decade, yet evaluation of trap type effectiveness has remained a constant source of uncertainty. In this two-week field experiment, we compared effectiveness across 12 standard and modified trap designs in catching the most crayfish while catching the least bycatch. There were differences observed across the traps tested in the number of caught crayfish(X2 =257.67, p-value <0.001), chub (X2 =354.39, p-value <0.001), and tadpoles (X2 =57.31, p-value <0.001). Specifically, the most effective trap for catching total crayfish was the black cylindrical mesh trap, followed by the red mesh trap, and both the standard and modified black minnow traps. When managing for crayfish in arid-environment streams, we recommend deploying a combination of trap types in order to maximize crayfish catch efficiency and limit negative impacts on native fish and tadpole bycatch.
Joseph Curti (Primary Presenter/Author), Mountains Restoration Trust, firstname.lastname@example.org;
Angela De Palma-Dow (Co-Presenter/Co-Author), Lake County Water Resources Department, Adepalmadow@gmail.com;
C. Emi Fergus (Co-Presenter/Co-Author), The National Research Council, email@example.com;