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We measured the critical swimming speed of juvenile white sturgeons Acipenser transmontanus equipped with externally attached dummy ultrasonic transmitters and of untagged control fish in the laboratory. White sturgeons ranging from 31.9 to 37.0 cm fork length were subjected to one of three treatments: control (handled but not tagged), tag attached below the dorsal fin, and tag attached with the anterior insertion point between the fourth and fifth dorsal scutes. Although transmitters were of recommended weight, we found that the swimming performance of tagged white sturgeons was significantly less than that of untagged control fish. Swimming performance of tagged fish was not differentially affected by tag location. Our results suggest that data from ultrasonic telemetry studies of externally tagged juvenile white sturgeons should be interpreted with caution due to the reduced swimming performance caused by external transmitters.

This review examines the ecological, economical, and public health significance of chironomids and provides examples of chironomid invasions via international shipping and the subsequent local and regional impacts. Dispersal and adaptation mechanisms as facilitators of chironomid invasions are presented, and control methods are discussed. Impacts ranged from increased nuisance occurrences to agricultural disruption. Anthropogenic activities including pollution-related decimation of aquatic benthic communities might allow introduction of invasive chironomids. Chironomids can inhabit many environments, including eutrophic lakes and wastewater treatment areas, and may accumulate contaminants in high concentrations. Health concerns include the association of chironomid egg masses with Vibrio cholerae, roles of chironomids as vectors for avian botulism, and effects of chironomid chemicals as human allergens. Therefore, the presence of new chironomid species in an environment may present threats to public health and local ecosystems.

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