Across 600 miles of California coastline, hundreds of nearly dead sea lion pups are stranding themselves on the beach. They’re thin, weak, confused and much too young to be away from their mothers. What’s going on?
That’s what marine researchers have been trying to figure out for some time now.
California sea lions are born in the Channel Islands off southern California. When life is good, they remain with their mothers for almost a year. They learn to fish and feed themselves before their mothers wean them and send them off into the world.
For some reason, in 2013 mother sea lions were abandoning their pups much too early, almost guaranteeing them an early death. It’s happening again in 2014. Something is very wrong.
An Incredible Number of Starving Sea Lions
Typically, the Marine Mammal Center in San Pedro, Calif., might see 20 or so malnourished California sea lion pups in any given year. Over the past two years, however, the numbers have skyrocketed. A staggering 1,600 California sea lions were discovered stranded along the California coast during 2013, a phenomenon scientists called an “unusual mortality event.” Watch a CNN news report about this problem here:
With only half of 2014 gone, the Marine Mammal Center has already treated 100 abandoned pups. Most of them are so young they’ve never been taught how to catch and eat a fish. Without the help of rehabilitation centers, these pups have no hope of survival. Even with help, only 60 percent of the rescued sea lions at the center survive to be released again to the wild.
“There’s a disturbance in the ocean right now,” Dr. Shawn Johnson, director of veterinary science for the Marine Mammal Center, told Time magazine. “For some reason, [pups are] being abandoned by their moms.”
Between Santa Barbara and Sean Diego, five marine mammal rehabilitation facilities are seeing the same problem. The condition of the sea lions pups washing up onshore is cause for great concern.
“The ones we are seeing are basically starving to death,” Dr. Johnson told SFGate.com. “It’s definitely a mystery. We’re hoping it’s not the new norm.”
Scientists Struggle for Answers
Theories abound as to what’s causing this sea lion catastrophe. There have been sea lion die-offs in the past, which scientists attributed to causes like bacterial infection or the negative effects of El Nino. This problem, however, is different.
The prevailing opinion of researchers from the National Oceanic and Atmospheric Administration (NOAA) is that fish stocks are much too low and mother sea lions just can’t find enough high-nutrient forage fish to eat. They go off looking for food and never return. Fish stocks are indeed shrinking, as any southern California fisher can attest. In December 2013, for example, authorities required fishers on the West Coast to reduce their sardine by more than a third – from 18,073 metric tons to 5,446 metric tons — to avoid overfishing the species.
Another contributing factor may be algae blooms or “red tides,” which create a dangerous neurotoxin buildup in the sea lion’s primary food sources, herring and sardines. Such blooms are also killing sea birds that eat affected shellfish, anchovies and mussels. This buildup, domoic acid toxicity, causes frightening symptoms such as convulsions, seizures, tremors, foaming at the mouth, bloody discharge, paralysis and death.
Meanwhile, marine mammal rehabilitation centers work tirelessly, with dwindling funds, to feed the avalanche of desperate pups. Because so many of these babies have not yet learned eat a whole fish, volunteers feed them a sort of fish smoothie by blending nutritious, high-fat fish like herring with fish oil and water.
It’s an expensive proposition. A single meal for one pup costs $10. The Marine Mammal Center can go through 1,000 lbs. of fish a day at $1 a pound. That’s $30,000 a month just to keep feeding all the animals in their care.
Hoppie: The Poster Pup for the Abandonment Crisis
Remember the story of Hoppie, the sea lion pup found wandering in an orchard miles from water? He’s apparently just one of the many pups who’ve lost a mother and didn’t know how to survive. His story turns out well, however.
According to a post on the Marine Mammal Center’s Facebook page, Hoppie gained 10lbs. while under their care and was successfully released back to the ocean recently. The center says: “He won’t get lost again. We sent him off with a little water-proof map.”
NOAA and other marine mammal scientists continue to investigate, while sea lions keep struggling to survive. Let’s hope that Hoppie’s happy ending is an omen for the future.
Photo credit (all images): Thinkstock