The Potential Use of Ultrasound to Control the Trematode Bolbophorus confusus by Eliminating the Ram's Horn Snail Planorbella trivolvis in Commercial Aquaculture Settings

One method in the investigation of acoustics to improve aquaculture production is the use of ultrasound to control the trematode Bolbophorus confusus in commercial catfish Ictalurus spp. ponds. The trematode population can be controlled by eliminating the host, ram's horn snail Planorbella trivolvis, which is typically accomplished with chemical treatments. The work presented here investigates snail elimination via exposure to high amplitude ultrasound. Initial laboratory tests indicated that a commercially available sonicator (operating at 20 kHz) is capable of quickly killing individual snails in test tanks. More thorough testing indicated efficacy rates of at least 35% (potentially 65%) on batches of 10 snails in a reverberant environment. The experimental setup of these initial laboratory tests provided nearly 20 decibels of gain in sound levels compared to what is expected in ponds. This is due to reverberation from the air surrounding the tank walls, as opposed to absorption at the bottom and sides of ponds. Additional tests were run in an anechoic environment to mimic pond absorption and showed lower efficacy rates, indicating that the final field deployable device will need to compensate for the 20 decibels of gain. The work presented here constitutes the proof of concept and basic research for the design and development of a field deployable system capable of killing a significant percentage of a snail population with no or reduced amounts of chemicals.