Assessment of Internal and External Antenna Configurations of Radio Transmitters Implanted in Smallmouth Bass

Abstract

Researchers conducting fish telemetry studies using the intraperitoneal surgical implantation of radio transmitters with whip antennas can configure the antenna to exit the body cavity through a small puncture wound (external) or leave the antenna coiled within the body cavity (internal). We conducted a behavioral field study to examine movement patterns of smallmouth bass Micropterus dolomieu carrying radio tags with internal or external antenna configurations. Fish movements, number of days tracked, and number of detected signals did not differ between internal or external treatment groups. To complement the field study, we conducted a laboratory investigation to examine possible effects that these treatments (antenna type) may have on the swimming performance of smallmouth bass by comparing critical swimming speeds. Swimming performance was not significantly altered by the surgical procedures related to transmitter and antenna placement. Our results also suggest no significant differences in swimming performance or movement rates of fish related to antenna configuration. However, transmitter signals were attenuated with the internal antenna configuration. As such, decisions regarding which antenna configuration to use should be based on fish morphology, study objectives, and site-specific environmental conditions.