On Monday NBC San Diego first reported an increasing number of California sea lion pups stranded and starving along the coast of Orange and San Diego counties. By Tuesday March 12 the number of pups needing emergency medical care was so great that marine wildlife rescue groups had declared a state of emergency. They feared that the number of expected pups would surpass their ability to house and rehabilitate them.
Susan Chivers, a biologist with the National Marine Fisheries Service, spoke with media on March 12. “We don't know what the problem is now. “What we're seeing is a lot of skinny pups which suggests they’re not getting sufficient nourishment, and dying of starvation basically." The typical sea lion pup is round and robust. Recent photos of stranded pups along the coast show evidence of dehydration and malnourishment.
“There’s something going on oceanographically that there’s not sufficient food available for the moms to nurse their pups or the pups, as they’re starting to eat on their own, to find,” Chivers continued. "Basically, you can see its backbone. You can see its shoulder blades," she said.
I wondered if the problem might have to do with the mega-pods of dolphins witnessed in the waters off San Diego in the middle of February. Sea lions and dolphins eat the same diet of fish, herring and other food sources and the pod might have wiped out the supply for mothering sea lions.
In an exclusive interview Chivers responded with the following statement: “I think we may be seeing a shift in prey resources that is impacting marine mammals in the Southern California Bight. The large sighting of dolphins a few weeks ago was likely due to animals following their prey. I think it likely that the mother's of sea lion pups are having a difficult time finding enough prey to sustain lactation. These species likely feed in different regions making it fairly unlikely that the two species are competing directly for prey resources. We'll know more as the data come in on the cause of death and current oceanographic conditions.”
Clearly more research is needed. Part of that process will be to perform necropsies on the dead sea lion pups that have been found. Scientists are hoping that finding the exact cause of death may help them find out what is happening. Global climate changes which affect the temperatures of the ocean may prove to be part of the puzzle. It is blamed for the dramatic increase in small box jellyfish that hampered Diana Nyad during her marathon swim between Cuba and the Florida Peninsula.
Northern California is not seeing the same numbers of stranded sea lion pups according to the Marine Mammal Center in Sausalito.
Typically Southern California rescuers doesn't encounter animals in need of medical attention until April or May. This year, higher numbers of starving sea lions began coming to shore in January, according to Pacific Marine Mammal Center spokeswoman Melissa Sciacca, and the numbers are reaching epidemic proportions.