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SC/69A/CMP/11
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Resource ID
19965
Access
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Document Number
SC/69A/CMP/11
Full Title
Southern right whale mortalities at Península Valdés, Argentina: updated information for 2018-2022
Author
Sironi, Mariano, Agustina Donini, Victoria J. Rowntree, Matías Di Martino, Santiago Fernandez, Marcos Ricciardi, Adrián Rodríguez, Macarena Agrelo And Marcela M. Uhart
Authors Summary
Southern right whales (Eubalaena australis) have experienced high mortality rates at Península Valdés, Argentina in recent years. In 2003, the Southern Right Whale Health Monitoring Program was established by a consortium of NGOs to monitor the health status of this population by post-mortem examinations. Here we update information for the 2018-2022 seasons (no data for 2020 due to COVID-19 restrictions). A total of 928 dead whales were recorded on the Península Valdés calving ground since 2003. The annual number of dead whales for the study period was 23 (2018), 17 (2019), 45 (2021) and 73 (2022) totaling 157 individuals in four calving seasons. Most of the dead whales were calves (63%), followed by adults (30%) and juveniles (7%). As in previous years, the majority of dead whales were recorded in Golfo Nuevo (GN, 70%) and the remaining whales died in Golfo San José (GSJ, 30%). However, the distribution of strandings was very different among years. For instance, in 2019 all calves (10/10; 100%) died in GN and all adults (6/6; 100%) died in GSJ. However, in 2022 dead calves were distributed between the two gulfs (29/42 or 69% in GN and 13/42 or 31% in GSJ) and contrary to 2019, all but one adult died in GN (27/28 or 97%). All whales were dead when reported or found. Post-mortem examinations were performed when carcass condition allowed and when strandings were not on public beaches where only non-invasive sampling is performed. Potential causes of mortality will be discussed elsewhere. Of note, the adult female mortality in Golfo Nuevo in 2022 was the most extreme adult mortality event on record for the species since 1971. Results on the role of Paralytic Shellfish Poisons (PSP) in the mortality event of 2022 are reported in a separate paper.
Publisher
IWC
Publication Year
2023