CIRCADIAN RHYTHMS OF BOTTLENOSE DOLPHINS´SOUNDDOLPHINS´SOUND EMISSION IN CAPTIVITY. IS IT SIMILAR TO NATURE?

GIARDINO, GISELA; JAVIER OLGUIN; RICARDO O. BASTIDA; ELENA PAPALE; ALEJANDRO SAUVIDET; SALVATORE MAZZOLA; MARIA CERAULO; DIEGO RODRÍGUEZ; GIUSEPPA BUSCAINO

Mar del Plata

Congreso; XVIII CONGRESO LATINOAMERICANO DE CIENCIAS DEL MAR; 2019

Asociación Latinoamericana de Investigadores de Ciencias del Mar (Alicmar)

Bottlenose dolphins produce varied types of sound, including clicks, whistles, and bursts. We know that dolphins in nature have more click production at night during feeding activities and a peak occur at crepuscular/dawn hours, but dolphins in captivity are involved in several training/feeding sessions per day that are diurnal. To better understand the species? sound production and behavior we compared the circadian rhythmic with free ranging dolphins in order to know if the captivity modify their vocal behavior.Underwater sounds were recorded continuously, 24 h a day, for nine selected days with autonomous recorder with sampling frequency of 192 kHz at 16 bit. Sounds analysis was manually performed using Raven Pro (for modulated sounds) or automatically using AvisoftSASlab Software (for impulsive signals). Subsampling of the data was carried out by selecting two-min record every 10 minutes in one day. We summed the number of each vocalization type (whistles and click) in each sub-sampling period and modelled with Generalized Additive Model them against the hour of the day. We found that there is marked circadian rhythm of clicks and whistles, in either presence or absence of show activity. The peak of maximum activity occurs at dawn (from 05:00 to 10:00) with a marked decrease at 15:00 and then at midnight.The circadian rhythm found in echolocation and communicative signals (whistles) were similar to that found in nature. These preliminary data demonstrated that in captivity, bottlenose dolphins also maintain their native sound production patterns. Further data and analysis is going to be collected in the next future.