Tracking Headstarted Turtles with Radio-Telemetry

We conducted radio-telemetry surveys from 2014 to 2019. During the turtle active season, from May to mid-September, we tracked turtles two to three times weekly, whereas in the non-active season, we tracked once monthly. Each year, a subset of headstarted turtles were outfitted with radio transmitters (Advanced Telemetry Systems R1600) and tracked for at least one year. To determine which turtles would receive a radio transmitter, headstarted turtles from each cohort were separated into two groups based on presumed sex (i.e., incubation temperature). Each turtle was assigned a unique number and using the random number function (= RAND) in Excel, a turtle was selected to be outfitted with a radio transmitter. Each year, more female turtles were selected for radio transmitter attachment. The combined weight of the transmitter and the epoxy was approximately 10 g, which was less than 10% of the average turtle body mass. Headstarted turtles were tracked using an R410 or R4000 Receiver (Advanced Telemetry Systems, Inc., MN). We tracked 10 turtles from the 2014 release cohort, 21 turtles from 2015, 24 from 2016, 16 from 2017, 22 from 2018, and 23 from the 2019 release cohort. We excluded the 10 individuals from the 2014 release cohort in our analysis because of missing data. Most turtles were only tracked for a year, but a few headstarted turtles remained in the study to be radio-tracked for 2–5 additional years (Table 1). The turtles that remained in the study were affixed with a new radio transmitter each year.