The numbers coming in, along with the graphic pictures of hundreds of dead sea lion pups, is disheartening and gut-wrenching. But marine scientists continue to record their findings from the beaches of northern Chile, Peru and further north into southern California.
In Chile, most of the dead pups have been found on a small peninsula in the northern part of the country over the past three months, and are just a small part of a massive die-off being seen elsewhere along South America’s Pacific Coast, according to WTVR-Richmond.
Researcher Carlos Guerra-Correa, who is director of the Regional Center for Environmental Studies and Education at Antofagasta University, was quoted by CNN as saying, “This is happening along the entire coast of northern Chile and we’re getting reports that it’s also happening in Peru, our neighbor to the north. We could be talking about hundreds of sea lions washing up ashore dead in the entire region.”
Marine researchers regularly conduct their studies around the Mejillones Peninsula in Antofagasta province, where the South American sea lion (Otaria flavescens) has been affected by the die-off. Guerra-Correa says he is particularly concerned because the majority of the sea lions have been newborns, although a few juveniles and adults have been found.
“Some of the dead animals we have found still had their umbilical cord attached,” Guerra-Correa said. “We found one with a placenta.”
What are the reasons behind all the deaths?
As everyone knows by now, we have been going through one of the most powerful El Nino weather cycles ever recorded. The recurring weather pattern brings warmer waters across the pacific to the South American coastline. However, the warmer waters don’t have the level of phytoplankton nutrients that colder waters have.
Sardines and anchovies need phytoplankton for food, and sea lions need the fish for survival. It’s all part of the bigger food chain. To put it simply, the sea lions are starving because the food chain has been damaged. “Starvation is primarily affecting female sea lions in the latter stages of pregnancy. That’s why their babies are dying at birth or being miscarried,” said Guerra-Correa.
He added that over-fishing is also aggravating the problem because it reduces the number of feeding options available to sea lions.
The plight of the California sea lion is not any better
California sea lions, (Zalophus californianus), are having the same problems as their South American kin. The sea lion pups are born in the summer months in the Channel Islands, off the coast of Southern California. This year, the islands are littered with the corpses of sea lion pups.
“There are a lot more dead. We haven’t ever seen anything like this,” Sharon Melin, a wildlife biologist with the Alaska Fisheries Science Center of the National Oceanic and Atmospheric Association (NOAA) in Seattle, Washington, told Vice. NOAA has been tracking the pups on their island rookeries since 1979.
“What’s really disturbing are the pups still alive,” said Melin. “They’re racks of bones working so hard to survive and trying to suckle from mothers that aren’t theirs.” Melin went on to say that even in September last year when the pups were three months old, their weight was below average. Pups normally stay with their mothers until they are 10-months-old and usually wean in April.
It is just a horrible vicious circle of events affecting the sea lions, both in South America and in California. To make matters worse, the pups that do survive and go on to become adults, may not be able to produce viable pups due to the prolonged period of malnutrition they have gone through. Only time will tell.
