Acoustic Tag Attachment Methods for Tracking Hatchling Sea Turtles

The poorly understood movements of sea turtles during the ‘lost years’ of their early life history is currently characterized as a ‘passive drifter’ stage. Biologging technology has the ability to answer dispersal questions, but the small body size of these stages requires particular consideration that such tagging does not significantly impede their buoyancy or movements. In this study, we tested methods for attaching miniature acoustic transmitters (Vemco V5 tags) to approximately 8-week-old hatchery-reared green sea turtles (Chelonia mydas) (n=12). Each animal’s speed, direction, and swimming behavior were recorded under three scenarios: control, direct Velcro attachment to the carapace, and harness attachment, to determine if there was significant change between treatments. The turtles’ swimming speed was most greatly affected with the harness attachment and was significantly slower compared to the control (Repeated measures ANOVA, p<0.05). Turtles also spent more time near the surface (<15 cm depth) when the harness was attached than during the control or direct Velcro attachment. No significant change in behavior was observed when the tag was attached directly with Velcro and will therefore be used next in field trials to monitor movements of small, hatchling turtles to understand the dispersal and survival of these vulnerable marine species.