Argentina investigates unusual deaths of southern right whale calves

Scientists are investigating an unusual surge in the deaths of southern right whale calves along the Patagonian coast of Argentina. Scores of carcasses have washed ashore near Península Valdés and Puerto Madryn in the Chubut province, an area that serves as a critical breeding ground for the species.

Marcela Uhart, a veterinarian with the One Health Institute at the University of California, Davis, is leading the Southern Right Whale Health Monitoring Program's investigation. Researchers note that the high number of deaths is an abnormal event compared to 23 years of population monitoring.

A leading hypothesis suggests that marine bacteria may be causing fatal infections. These infections could enter the calves' bodies through wounds inflicted by kelp gulls. While adult whales can surface with only their heads exposed to avoid seabird attacks, calves have not yet mastered this maneuver, leaving them vulnerable to pecking that can compromise their skin and blubber.

Field teams are using boats, aircraft, and drones to locate carcasses and collect skin and organ samples. Preliminary laboratory tests in Tandil have confirmed the presence of bacteria, but researchers are still working to determine if these microorganisms are the direct cause of death.