Southern Right Whales found dead in Chubut, Argentina

Authorities and scientific teams in Chubut, Argentina, are investigating an unusual increase in Southern Right Whale mortality near Puerto Madryn and Península Valdés. Recent reports indicate several whales, including large adults, were found dead within a 48-hour period, raising concerns that the 2026 season could surpass the record mortality of 113 calves documented in 2012.

An inter-institutional operation involving the Coastal Fauna Network, the Southern Right Whale Sanitary Monitoring Plan, and local environmental secretariats is conducting necropsies and collecting biological samples. While previous deaths in calves were linked to the bacterium ‘Erysipelothrix rhusiopathiae’, recent adult carcasses do not show preliminary signs of this specific pathogen.

Researchers are currently evaluating alternative hypotheses, including systemic infections caused by marine bacteria, dietary changes, or natural toxins resulting from environmental events such as red tides (harmful algal blooms). The investigation has expanded to include water and mollusk sampling in Nuevo and San José gulfs to assess broader environmental conditions.