Full Breakdown
Unusually High Mortality of Southern Right Whale Calves in Argentine Patagonia
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Core Event
Since June, dozens of dead southern right whale calves have washed ashore on the beaches of Chubut province, including Puerto Madryn and the nearby Valdés Peninsula. The deaths have been described by scientists as an “exceptionally high” mortality rate for the current breeding season, prompting a joint investigation by provincial authorities and marine-mammal researchers.
Background & Context
The coastal waters of Puerto Madryn and the Península Valdés constitute one of the South Atlantic’s principal calving grounds for the southern right whale (*Eubalaena australis*). Each year, large numbers of adults gather to mate and raise their young. In the 2025 census, a record 2,110 whales were counted, of which more than 800 were juveniles. The 2026 survey recorded 1,375 whales, including roughly 400 calves, a decline that falls within the species’ normal population fluctuations.
Data & Statistics
Official Statements & Responses
Mariano Coscarella, a researcher at the Marine Mammals Laboratory of the National Scientific and Technical Research Council (CONICET), explained that while some calf deaths are part of natural population dynamics, the current season’s mortality is unusually high. He noted that initial analyses point to a common marine bacterium—potentially *erysipelas*—as a leading hypothesis, but emphasized that the investigation remains open and that human influences cannot be completely ruled out.
The Government of Chubut confirmed that it is collaborating with the scientific community and specialized teams to survey the specimens, collect samples, and conduct laboratory analyses. Authorities have so far found no direct evidence linking the deaths to anthropogenic factors.
Verbatim Quotes
- “The mortality rate among calves is quite high, especially this season,” — Mariano Coscarella