Electronic Theses and Dissertations

Date of Award

1-1-2011

Document Type

Dissertation

Degree Name

M.S. in Physics

Department

Physics and Astronomy

First Advisor

James P Chambers

Second Advisor

Cecille Labuda

Third Advisor

Joel Mobley

Relational Format

dissertation/thesis

Abstract

As one step in the investigation of using acoustics to improve aquaculture production, work was pursued on the possible use of ultrasound to control the Bolbophorus trematode in commercial catfish ponds. The trematode population can be controlled by eliminating the host ram's horn snail via exposure to high amplitude ultrasound. Initial laboratory tests indicated that a commercially available sonicator (operating at 20 kHz) is capable of killing individual snails in fish tanks. More thorough testing indicated efficiency rates of approximately 35% on batches of 10 snails. In addition to the snails killed immediately, there was evidence that the sonication technique caused mortal wounds that caused significant death a few days after the tests. The experimental setup of these initial tests provided nearly 20 dB of gain in sound levels compared to what is expected in ponds due to reverberation from the air surrounding the tank walls. Tests were run in an anechoic environment to mimic pond absorption and showed lower efficacy rates, ranging from 0% at short durations to 25% at 90 seconds. Several transducers operating between 80-500 kHz were built and calibrated to provide alternate driving frequencies but could not provide enough power to be of any benefit. The work presented here constitutes the basic research and proof of concept behind the design and development of a field deployable system capable of killing a significant percentage of a snail population.

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