Scientists in Argentina are racing to determine why an unprecedented number of southern right whale calves have washed ashore dead along the Peninsula Valdés coastline, a key breeding ground in Chubut province.
Local investigation
Marcela Uhart, a veterinarian with the One Health Institute at the University of California, Davis, leads the Southern Right Whale Health Monitoring Program. She notes that 23 years of monitoring this population allow researchers to label the current mortality spike as “unusual.”
Uhart and a team of biologists, veterinarians, and park rangers are combing the beaches and patrolling the waters by boat, plane, and drone to collect carcasses. They photograph and preserve skin and organ samples for laboratory analysis in Tandil, a city farther north.
Possible cause
The leading hypothesis is that marine bacteria are infecting the calves after injuries inflicted by kelp gulls. Adult whales have learned to surface with only their heads exposed, keeping their backs out of gull reach, but vulnerable calves cannot perform this maneuver.
Preliminary testing has already detected bacteria in the tissues, but researchers are still culturing the samples to identify the specific microbes and confirm whether infection caused the deaths.
Why now?
Even if bacteria are confirmed, scientists must explain why they have become so lethal this year. Changes in marine conditions—such as warming sea temperatures possibly tied to climate change or El Niño—could be creating a “perfect storm” that weakens the calves’ immunity.
Uhart stresses that understanding the trigger is essential for protecting the species. “If the cause relates to something that we are doing as humans, then we need to change that,” she said.
Broader context
Southern right whales were hunted to near extinction in the 19th and 20th centuries but have rebounded since gaining international protection in 1935. Nonetheless, the species still faces threats from declining food supplies, fishing gear entanglements, oil spills, and ship strikes.
Should large‑scale calf losses recur, the recovery of the population could be slowed. By pinpointing the cause, researchers hope to develop strategies that safeguard these iconic marine mammals for future generations.
Original reporting: Alexandria, VA News – WTOP News — read the source article.
