Louise B. Brooks, James T. Harvey and Wallace J. Nichols. 2007. Tethered GPS/VHF transmitters: A high-tech, low-cost tool for fine scale, in-water tracks. In: Mast, R.B., Hutchinson, B.J., and A.H. Hutchinson, compilers. 2007. Proceedings of the Twenty-Fourth Annual Symposium on Sea Turtle Biology and Conservation. NOAA Technical Memorandum NMFS-SEFSC-567, 205 p.
We used tethered VHF/GPS transmitters to track sub-adult East Pacific green turtle (Chelonia mydas) in Bahía Magdalena, Baja California Sur, Mexico. This method utilized GPS technology to acquire fine-scale position data and VHF telemetry to locate and monitor the animal. GPS and VHF units were housed in a buoy that floated at the end of a 10 m tether. Tethers were attached to the turtle with a fail-safe release design that broke in the event of entanglement or resistance. Preliminary assessment determined that habitat characteristics and sea turtle behavior were suited to accommodate the unit. Turtles were tracked at depths of 1 to 8 m and for distances of up to 40 km per day. Use of the tethered transmitter units yielded consistently high quality data without compromising safety of the animal. Cost remained low in comparison to other tracking techniques. These data will be used to describe foraging ecology and to aid reserve design as part of an integrated sea turtle conservation program for the Bahía Magdalena region.