Malnourished California sea lion pups on road to recovery after El Niño wrecked their ecosystem
After a year of dangerous conditions and low population growth, scientists in California were happy to report that 2016 was a success for thousands of sea lion pups.
A diminished food supply and cool ocean waters led to malnourished and weak pups. In 2015, a record-breaking 4,000 sea lion pups stranded (attempted to find shelter onshore), more than double that of 2014, according to the National Oceanic and Atmospheric Association (NOAA).
Sea lion pups stranded along the California coast in record numbers, and were often malnourished by the time they arrived at rescue and rehabilitation centers in 2015. (Photo/NOAA)
Just over 2,000 pups were stranded in 2016. While still more than normal, experts are happy with the trend.
"...sea lion prey, especially small fish such as sardines and anchovy, were not available in great enough numbers to nursing mothers, making it difficult for mother sea lions to find food and produce the milk necessary to feed growing pups [in 2015]," NOAA said in a press release.
Most strandings occurred in Southern California.
Warm ocean waters in 2015, due in part to El Niño, contributed to the pups' plight.
El Niño occurs when ocean water temperatures rise above normal across the central and eastern Pacific, near the equator. The El Niño event that stretched from 2015 to 2016 was among the strongest on record, NOAA said.
Ocean waters began cooling as El Niño transitioned into La Niña, when water temperatures fall below normal along the equatorial Pacific, during 2016.
As ocean temperatures level out, researchers are optimistic for a return to typical ecosystem conditions.
Recent research by NOAA scientists and other researchers at the San Miguel and San Nicolas sea lion colonies on the California Channel Islands indicates that pups are better nourished in 2016. (Photo/NOAA)
In the spring of 2016, federal fisheries banned all sardine fishing off the West coast due to the dramatic drop in population. Between 2007 and 2016, the Pacific sardine population plummeted by 90 percent, NOAA fisheries reported.
Anchovies also faced a similar battle. As a species, they do not migrate toward cooler water when temperatures rise. So when waters heated up during El Niño, population numbers fell due to the unstable conditions.
Rehabilitation centers were packed with malnourished seal lion pups in 2015. (Photo/NOAA)
The improved ocean conditions and return to a more abundant food supply in 2016 led to a brighter future for California's sea lion pups, scientists said.
Still, they are hoping that 2017 treats seal pups off coastal California better than 2016. Scientists will continue to monitor mothers and pups at their island colonies. So far, indications are strong that 2017 will lead to a brighter future for the genial animal.
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