Preliminary report on a new baleen whale mortality at the Golfo de Penas, southern Chile, that occurred late 2019 summer
Carlos OlavarrÃa, Keri-Lee Pashuk, Greg Landreth, Daniel Torres, Francisca Rodriguez, Fernanda P. Arrau, Lilian Reiss, MarÃa BelÃ©n GutiÃ©rrez, William Darwin, Vreni HÃ¤ussermann, Carolina S. Gutstein, MarÃa JosÃ© PÃ©rez-Ãlvarez, Mauricio Ulloa et al.
HÃ¤ussermann et al. (2017) reported the largest mass mortality event of any baleen whale. It took place in the Golfo de Penas, Southern
Chile, during early 2015. All identifiable whales were sei whales (Balaenoptera borealis). A few more whales were recorded dead
in early 2016 (n=16) in the same area. Here we preliminarily report a new mortality event that occurred in early 2019. Overall, 27 sei
whale carcasses were found in the northern Golfo de Penas, in the areas of San QuintÃn (21) and Seno Newman (6) (with a similar
estimated time of death). Skin and bone samples were taken to genetically confirm species identification and to complement ongoing
population analyses (PÃ©rez-Ãlvarez et al. 2019). Average length was 11.5m (ranging between 9.7m and 14m), indicating most of the
whales were weaning and immature (when compared with Southern Hemisphere whaling data). A few sightings of live sei whales,
including adults and juveniles were recorded at Seno Newman while searching the shoreline. A wider search at the Golfo de Penas
area is currently being undertaken using very high resolution satellite imagery, after being tested for the 2015 event (Fretwell et al.
accepted). We also report similar scale of mortalities during early 2017 (n = 19) and 2018 (n = 8). These mortality events highlight
the Golfo de Penas as an important area for sei whales during austral summer, stress the need for a better understanding of these
events and their likely environmental triggers, raise the alarm of a recurrent event that has been happening (at least) since 2012 with
unusual regularity and highlight the need for continuous and systemic monitoring in the area.