Pinger response trials with Chilean dolphins in southern Chile

Short term behavioral responses of Chilean dolphins (Cephalorhynchus eutropia) to acoustic alarms, or pingers, were tested using exposure-control experiments (pinger on/off treatments). Field trials were conducted in the south-eastern Chiloe Archipelago  between February and April of 2013. BananaBP154 pingers (FishTek Marine) were used for the tests. Static passive acoustic monitoring (PAM) techniques were used at two sites (Bahia Yaldad and Canal San Pedro) and land based observations, which included theodolite tracking, were also conducted at Bahia Yaldad. Static PAM techniques and C-PODs were used to determine the effects of a single pinger on echolocation rates and movement patterns. Fifty seven groups of Chilean dolphins were tracked with the theolodite, with 45 groups providing good resolution movement data within the vicinity of the pinger. Visual data are currently being analysed to determine effects of a single acoustic alarm on movement patterns, grouping behavior and spatial area use of the dolphins. Acoustic encounter rates of Chilean dolphins at the six C-PODs are currently being analysed. Preliminary analysis suggest pingers are unlikely to have caused substantial behavioral changes in Chilean dolphins.