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The Potential Use of Electricity to Control Burrowing Shrimp in Oyster Aquaculture Beds

Dumbauld, Brett, Harlan, Lisa
North American Journal of Aquaculture 2009 v.71 pp. 178
aquariums, burrowing, burrows, electric current, electric field, experimental design, exposure duration, mortality, oyster culture, oysters, paralysis, pest control, shrimp, swimming, Pacific States
Thalassinidean shrimp cause significant problems for oyster aquaculture in the Pacific Northwest (USA), where oysters succumb to the physical sediment disruption generated by the burrowing activity of these animals. Although electrofishing is a commonly used technique to capture fish and some invertebrates in freshwater, applications in marine systems are limited due to the high conductivity of the water medium. Experiments conducted in aquaria showed that burrowing bay ghost shrimp Neotrypaea californiensis responded best (forced swimming with directed movement) to a pulsed DC waveform with optimal parameter settings of 1 V/cm, a frequency of 2 Hz, and a pulse width of 0.001–0.005 s. Unfortunately, when bay ghost shrimp were allowed to burrow into the substrate, they displayed a similar reaction but moved towards the bottom of their burrows, thus ruling out the envisioned use of this technique to attract them to the surface for capture. In experiments designed to induce mortality, it was possible to achieve paralysis or tetany by use of higher power with DC, pulsed DC, and AC, but the animals recovered unless (1) exposure time exceeded 60–100 s and (2) voltage exceeded 100 V (5 V/cm), frequency exceeded 120 Hz (pulsed DC), or both. These sustained levels would be difficult to achieve in the field due to the substrate, depth of the shrimp burrows, and high power necessary to obtain adequate field strength.