“Alarming Increase in Dead Sea Lion Pups: What’s Causing the Crisis?”
On May 7, Patrick Robinson, the director of UC Santa Cruz’s Año Nuevo Reserve, embarked on a boat trip to Año Nuevo Island to survey the sea lions that come to birth on this rocky outcropping north of Monterey Bay. What he found was a distressing sight – the shore was strewn with dead pups, many of which appeared to have been delivered prematurely or were stillborn. Similar reports were coming in from San Miguel Island in the Channel Islands and even as far south as Mexico.
Robinson noted that while it is not uncommon to see some dead pups at this time of year, the numbers he was witnessing were cause for alarm. With the peak of birthing season still weeks away, the situation hinted at a potentially serious and worrying trend. Stranding coordinators and biologists along the California coast echoed his concerns, acknowledging that something unusual was happening, although the exact cause remained unknown.
Tests were being conducted for bird flu, domoic acid, and other pathogens that have previously affected sea lion populations. Megan Moriarty, a veterinarian at UC Santa Cruz, reported an unusually high number of dead sea lion pups on Año Nuevo Island, with observations ranging from stillborn pups to malnourished adults. The situation was mirrored in the Channel Islands, a crucial nursery area for California sea lions.
Sharon Melin, a research biologist with the National Oceanic and Atmospheric Administration, highlighted various potential reasons for the mass mortalities, including environmental factors, infectious diseases, and toxins. While testing for bird flu was deemed necessary, there were no signs of respiratory or neurological issues in the affected sea lions.
The decline in anchovy populations off the California coast was noted as a possible contributing factor, with predators and seabirds showing signs of tracking more dispersed prey. Concerns were also raised about the broader ecosystem health, with reports of high brown pelican deaths and significant declines in chinook salmon populations leading to a ban on salmon fishing for the second consecutive year.
Despite the challenges, experts reassured that the California sea lion population overall remained healthy and robust. However, rescue centers were becoming overwhelmed with sick and malnourished pups, underscoring the urgent need for further investigation and conservation efforts to protect these iconic marine mammals.