Listening for right whales off Brazil: Present knowledge and future research

In the Southwest Atlantic, a key southern right whale wintering ground is found off southern Brazil. Aiming to collect reference information on the acoustic ecology of right whale mother-calf pairs in the region, we used two complementary passive acoustic monitoring methods. Recordings from autonomous archival devices were used to obtain the description of pairs’ vocal repertoire: call classes were established, temporal and frequency parameters of calls were measured and reported, and the existence of a diel pattern of vocal activity was investigated. Calling rate and contextual call usage were obtained through synchronized behavioral observations and acoustic recordings made using a dipping two-unit linear array. Current knowledge about the species vocal behavior off Brazil allows an increment in the use of PAM methods as a research tool. Therefore, our plans for future research include the use of multistory tags, sound propagation, and playback experiments, and long-term deployment of autonomous devices...