Variation in the vocal behavior of southern right whales (Eubalaena australis) in coastal Brazilian waters

Abstract

Currently there are three recognized species of right whales. The largest population is the southern right whale (Eubalaena australis), with circumpolar distribution in the southern hemisphere. One calving area for this population is in Brazilian waters, where increasing numbers of right whales have been sighted over the past decade along with an increase in anthropogenic activities including shipping traffic and fishing. The goals of this study were to describe the vocal behavior of southern right whales in Brazilian waters, assess the difference in vocalizations between areas with low and high human activity, and compare these results to studies conducted with North Atlantic right whales (Eubalaena glacialis) in the Western North Atlantic. Bottom-mounted archival acoustic recorders were deployed in October and November 2011 in two coastal locations in central Santa Catarina State, southern Brazil. One recorder was placed off Gamboa (27º56'S and 48º39'W, low traffic) and a second off Ribanceira (28º11'S and 48º37'W, high traffic). Automated detectors and noise statistic analysis tools developed for North Atlantic right whale upcalls were utilized to analyze the dataset. Calls produced by Brazilian whales were significantly lower in fundamental frequency than North Atlantic right whale calls and the implications for these results will be discussed.