Seasonal Occurrence of Southern Right Whales (Eubalaena australis) in Miramar (Buenos Aires Province, Argentina) Between 2016 and 2019

Abstract

In the past few years, Southern right whales (SRWs) have been increasingly observed along Argentinian coast, outside their known nursery ground near Peninsula Valdés. In Miramar, on the southwest of the Buenos Aires Province, occurrence of right whales has attracted the attention of the local community as a potential resource for tourism-related activities (e.g. whale watching). Systematic visual surveys have been conducted since April 2016 to assess the seasonal occurrence and relative abundance of SRWs in Miramar and to generate baseline knowledge to contribute to the conservation and assist in developing management actions. Land-based observations were made following a scan method from a high platform on Miramar’s waterfront with the aid of 7 x 50 Fujinon reticuled binoculars. A total of 449 Southern right whales was recorded during nearly 484 hours of observation. Despite of the effort throughout the year, the presence of SRWs was only registered during six months of year (May to October), a period that largely coincided in both 2016 and 2017. There was no significant difference between the average sighting rates in 2016 (x̅=1.22 ± 1.33) and 2017 (x̅=1.70 ± 2.01) (t = -0.37457, df = 10, p= 0.7158). Two years of systematic study in Miramar suggests that the seasonal abundance of SRWs peaks in August and September in this area. The continuation of this study will provide a better understanding of the habitat use and the factors that influence seasonal patterns of SRW occurrence off the coast of the Buenos Aires Province.