Abstract
A bstract We describe and evaluate a new telemetry system based on GSM (Global System for Mobile Communications) mobile phone technology that may provide mark‐recapture data for single year survivorship studies. These phone‐tags automatically attempt to send an SMS text message once every two days. The successful receipt of a text message ashore constitutes a resighting event within the coastal zone of GSM coverage. Haul‐out data and coastal location data are incorporated into the messages. Data are presented for a three‐month period (January‐March) following tag deployment on 59 gray seal ( Halichoerus grypus ) pups at the Isle of May (Scotland). An average of 15.5, 4.1, and 8.2 seals succeeded in registering within each three‐day period in January, February, and March, respectively. Tags registered with a wide geographical range of GSM radio cells on the Scottish and English east coasts, and also from Norway and Germany. Haulout records covering 54% of the animals' time were received. With future modifications to the tags, this figure should approach 100%. The median delay to network registration was 9.6 sec from a seal in the sea (not hauled out). These data show that GSM mobile phone telemetry is a useful technique to obtain haul‐out and mark‐recapture data.