Effects of ultrasonic algal control devices on fish

Abstract Getchell RG, George E, Rice AN, Malatos JM, Chambers BM, Griefen A, Nieder C, Rudstam LG. 2022. Effects of ultrasonic control devises on fish. Lake Reserv Manage. 38:240–255. Harmful algal blooms (HABs) can have serious impacts on both ecosystem services and human health, and several mitigation techniques have been developed to control them. Ultrasonic sound sources can disrupt developing algal mats, causing concern that the acoustic energy emitted from these devices may have deleterious health or behavioral effects on nearby fishes. We conducted field and laboratory studies on the effects of ultrasonic control devices on resident fishes. Field observations in Oneida Lake, New York, of the behavioral response of fish to the ultrasonic sound were conducted in shallow water using line transects, and in deeper water using hydroacoustics. No avoidance behavior was detected in either shallow or deep water while the ultrasonic devices were operating. Under controlled laboratory conditions, 7 recreationally or ecologically important fish species and local wild tadpoles were exposed to sound produced by the ultrasonic control devices for a 2 week period. No behavioral effects were noted while fish and tadpoles were monitored during the exposure interval. Finally, no significant or harmful histological or morphological alterations to the skin, fins, gills, or internal organs were observed on either fish or tadpoles when specimens were examined after the 2 week exposure period.