Using Vemco VPS Acoustic Telemetry Techniques to Quantify Fine-Scale, Long-Term Movement Patterns of Estuarine and Coastal Fishes

Quantifying fine-scale movement patterns and habitat use of coastal marine fishes has historically required active acoustic tracking techniques, which has limited the habitats and durations over which tagged individuals could be tracked.  Development of underwater acoustic-radio arrays (3 receiver time-difference-of-arrival) have allowed for higher spatial resolution of multiple individuals over longer periods of time; however, these systems have been spatially limiting and larger arrays have been cost prohibitive.  Recent development of the Vemco VR2W Positioning System (VPS) has enable researchers to cover much larger areas and derive finer-scale positional information on multiple individuals simultaneously.  We compared the VPS system in a shallow estuarine habitat (1.5 km², 1-4 m depth) and coastal shelf habitat (4.5 km², 26-65 m depth) with active tracking methods to quantify the efficacy of VPS for a range of applications.  The mean (± SD) positional accuracy of VPS of stationary transmitters deployed within an estuarine habitat was 2.64 ± 2.32 m (1-4 m depth), while over deeper, sand substratum habitats mean positional accuracy was 4 ± 5 m (26-65 m depth).  Positional accuracy decreases substantially along the outer edges of the array.  Home range estimates of fish double tagged and tracked within the estuarine habitats using both VPS and active tracking methods indicated that both methods provided comparable resolution.  Based on tests conducted in both habitats, VPS appears to provide suitable high spatial resolution of multiple individuals over longer periods of time.  Results indicate that this technology would benefit studies of fish movements important for assessing essential habitat use, contaminant exposure, gear interactions, and habitat restoration success.