The NMMF participated in the California sea lion unusual mortality event (UME) response and investigation.
From 2013 to 2017, an unusually high number of malnourished California sea lion pups washed up on Southern California beaches. The dire situation led NOAA to declare an unusual mortality event (UME). NMMF animal care experts provided support to Southern California marine mammal rescue facilities, as they faced an elevated number of patients. NMMF biologists and veterinarians supported NOAA’s work to determine the specific cause of the UME. Scientists currently believe that changes in prey availability, especially sardines, an important nutritional source for nursing mother sea lions, led to the increased prevalence of starving, stranded, and dead young animals.