Funnel Traps for Sampling Chinese Mystery Snails, Cipangopaludina chinensis (Viviparidae)

No previous studies have evaluated funnel traps (e.g., minnow or crayfish traps) as a method for sampling large freshwater gastropods. We captured Chinese Mystery Snails (Cipangopaludina chinensis), an invasive species in North America, in Rose Valley Lake, Pennsylvania, USA, as bycatch while sampling crayfishes with baited funnel traps with a 5-cm diameter opening. Mean catch per unit effort (CPUE)/trap was 1.2 CMS/night 6 0.3 SE (range = 0–6). We later tested baited vs. unbaited traps and found no significant difference in CPUE related to baiting, suggesting that snails entered traps incidentally. Funnel traps may be an alternative for sampling snails when conventional methods are limited by deep or turbid water, dense aquatic vegetation, or strong currents. If density estimates are desired, it will be necessary to derive and evaluate the relationship between CPUE in traps and observed estimates of snail density.