Hundreds of California sea lions and northern fur seal pups are expected to wash up on the Southern California coast through June as a result of warmer water temperatures, which is wreaking havoc on their food supplies, according to the National Oceanic and Atmospheric Administration.
Sea lions and seal pups have experienced low birth and survival rates in five of the last seven years and this year is expected to be at least as bad, NOAA experts said.
“They are too skinny and too small to effectively forage so they are washing up on the coast,” said Sharon Melin, a wildlife biologist for NOAA’s Alaska Fishery Science Center.
Melin said that sea lions in 2015 experienced the lowest birth weights in 41 years, since monitoring off the San Miguel Island rookery began.
Three-month-old female California sea lion pups had an average weight of 26 pounds, which is 31 percent of what is considered normal.
The average weight of Northern fur seal pups was about 14.5 pounds, about 3 percent below normal, and the third-lowest number in 41 years.
The only other time the weights were lower was in the 1982-83 and 1997-98 El Niño years.
Three-month-old sea lions and seal pups are highly dependent on their mother’s milk for nutrition. The mothers, however, are having difficulty finding food to support themselves and the production of milk for their young, according to NOAA.
“We are anticipating high numbers of stranded pinnipeds, who are going to need rehabilitation,” said Justin Viezbicke, California Stranding Network coordinator.
Both species typically feed off the Pacific sardine, northern anchovy, rockfish, Pacific hake and market squid. Warmer water temperatures have disrupted the food supply for the sea lions and seal pups, forcing the moms into perilous situations.
During El Niño years, the prey drops deeper into the ocean, forcing the females to dive deeper into the ocean to find their food, which reduces their energy and ability to return to their pups in a timely manner.
The longer the mothers are away, the longer the pup will have to fast as it waits for milk.
About 300,000 California sea lion pups exist, Melin said, which represents a robust population. At this rate, however, that could change.
“We would anticipate that if this continues, we will see a decline in the sea lion population,” Melin said.
“We don’t know what that number is going to look like. We don’t think it is going to be anything catastrophic or some huge collapse, but we would expect to show a declining trend.”
The conditions are so bad that Viezbicke said juvenile and adult pinnipeds may wash up on the shore. They urge the public to report the animals, but to keep their distance.
“These animals are in pretty poor condition and really aren’t able to do anything other than just lay there,” Viezbicke said.
“These are animals and they do have the potential to bite, especially if someone gets too close to them.”
— Noozhawk staff writer Joshua Molina can be reached at jmolina@noozhawk.com. Follow Noozhawk on Twitter: @noozhawk, @NoozhawkNews and @NoozhawkBiz. Connect with Noozhawk on Facebook.
