Readaptation to the wild of rehabilitated loggerhead sea turtles (Caretta caretta) assessed by satellite telemetry

Satellite telemetry was used to assess the readaptation to the wild of six loggerhead sea turtles after a long and complicated rehabilitation process. Their behaviour in the wild after release was compared with that of 12 healthy control turtles captured in the same region and fitted with similar satellite tags. The behaviour of the rehabilitated turtles was more variable than that of the control turtles and an outlier analysis revealed that only two of the six rehabilitated turtles did not differ in their behaviour from that of the control turtles. For the other turtles, the following anomalies were detected: a higher speed of travel, a negative cosine of the turning angle (the turtle turns back very often), a higher percentage of shelf use, a longer time at the surface at night, a higher averaged latitude during tracking, a shorter total tracking time and lower percentage of good quality fixes. Nevertheless, none of the turtles exhibited simultaneously these anomalies and only one turtle exhibited more than two anomalies. These results suggest that most rehabilitated loggerhead sea turtles survive in the wild at least for several months after release, even after a long and complicated process of veterinarian treatment, but many may exhibit behavioural anomalies, which casts doubts on the success of readaptation in the long run. Copyright (C) 2011 John Wiley & Sons, Ltd.