Rapid acquisition of marine mammal evoked potential audiograms by stranding networks. Free

Two portable evoked potential measurement systems were constructed for use by stranding networks to determine the feasibility of non‐expert collections of cetacean audiometric data. The systems were based on a customized version of the evoked response study tool with a simplified user interface designed for testing odontocetes. Stranding network personnel were provided one day of training on the system. Between January and April, 2010 the International Fund for Animal Welfare Marine Mammal Rescue and Research program attempted unsupervised AEP measurements on five live‐stranded odontocetes: a harbor porpoise (Phocoena phocoena, n=1), common dolphins (Delphinus delphis; n=3), and an Atlantic white‐sided dolphin (Lagenorhyncus acutus, n=1). Full or partial audiograms were obtained from the common and white‐sided dolphins. The skin condition of the harbor porpoise was sufficiently poor as to prevent consistent electrode contact during testing. No audiogram was obtained from this animal. Audiograms were typically dolphin in nature with an upper frequency limit approaching 160 kHz. Stranding network success at collecting odontocete AEP audiograms demonstrates that hearing tests can be conducted by non‐expert operators with a streamlined and simplified testing system. This approach will increase the rate at which audiometric data are collected from marine mammals.