Use of a Telemetry Positioning System to Track Largemouth Bass in a Littoral Habitat

The Sacramento-San Joaquin Delta in California’s Central Valley is a unique system with diverse management concerns, including declines of native fish populations and increases of non-native centrarchids like the largemouth bass (Micropterus salmoides). To examine the interaction between this fish and the community of submerged aquatic vegetation, we deployed an ultrasonic telemetry positioning system to record bass movements. Here we present some of the challenges we faced utilizing this new system in a shallow, vegetated habitat, in hopes that we can provide insight to other researchers using telemetric techniques for similar research objectives. Our primary challenge was limited positioning ability in dense vegetation. Additionally, to examine bass-habitat interactions, multiple sources of data had to be integrated at scales appropriate to the telemetric information. To achieve this, we quantified habitat characteristics through a combination of empirical data collection, real-time data sensors, and geospatial modeling approaches. We integrated these variables with animal positions using the program ’R’ to evaluate the effect of environmental factors such as vegetation density and diel period on behavioral patterns. In addition to the insight our results provide for ecosystem management, we believe our methods can inform fellow scientists examining habitat use in other dynamic environments.