Freezing mortality of faucet snails, Bithynia tentaculata: a viable method for equipment decontamination to reduce aquatic invasive species spread

Abstract

Reliable, inexpensive, and publicly accessible decontamination techniques are needed for equipment used in waters infested with aquatic invasive species. One such aquatic invasive species is the faucet snail (Bithynia tentaculata) that hosts several parasitic trematodes which have caused mass waterfowl die-offs in the United States and Canada. We examined freezing as a potential decontamination method using a household chest freezer. Snails were frozen in time increments of 0, 5, 10, 30, 60, 120, 180, and 240 min in dry conditions (water removed) and in water. Snails in dry conditions reached 100% mortality after 30 min while snails in water reached 80% mortality after 240 min. Snail mortality was inversely related to size, with larger snails requiring longer times to achieve mortality. Snails in water could tolerate freezing temperatures longer than snails in dry conditions. We determined that freezing is a viable decontamination method for contaminated equipment, but longer freezing times will be necessary for larger snails, especially when equipment is wet.