The news from California are drab. Apparently, the marine mammal rescue centers are flooded with starving sea lion pups and every day more arrive. Experts and volunteers are working overtime and the Sausolito Marine Mammal Rescue Center is begging for donations to help feed the large number of undernourished and often sick pups.
It started in December when the first malnourished pup was found. At five months old he should have still been with his mother and nursing for another 6 months. The rescuers who nursed him back to health until he was fat and strong enough to release first thought he was just an unusual case of a pup that lost its mother through some accident. But by March of this year, more than 1,200 California sea lion pups were admitted to rescue centers all along the California coast. The pups are much smaller than they should be this time of year and most are near death when they reach the centers.
Sea lion mothers are leaving their pups behind when they go looking for food. Without eating the mother can’t make the milk she needs to nurse the pup. However, food is nowhere near. The sea lions have to swim further and longer, leaving their pups waiting too long. The pups eventually leave the safety of the beaches trying to find food for themselves, but they are too young and not successful. What is causing this ocean famine? The full answer may be much more complex than what is given as the most likely cause at this time. The explanation given by NOAA states that strong winds from the South are blowing warmer water along the California coast. In other places I have seen mention of the El Nino effect.
The El Nino effect usually refers to the coast off Chile, where in some years a change in the prevailing winds causes onshore winds instead of offshore winds. Because this often happened right around Christmas time, the Mexicans called it “the Christmas child”, or short “the child (El Nino)”. For ocean productivity onshore winds are bad and offshore winds are good. Here is how that works: When the wind blows offshore, it gets the surface water to move offshore. Since water is a liquid, when you move some of it away, it is replaced by other water in its wake. That replacement water comes from the deep. In other words, the offshore wind starts a pump to get some of the deep water to the surface. Deep water is good for production because it has collected nutrients. When it comes to the surface it acts like fertilizer to the plantlike plankton organisms which are in turn food for the animal plankton, which are food for the fish, which are food for the sea lions. With no upwelling, the plankton bloom fails, the fish move away, and sea lion mothers find only empty shelves in their underwater pantries.
The California sea lion is a different species than our Stellar sea lion, which lives around Kodiak. At current the California sea lion population was not considered threatened. However, if the current crisis continues it is likely that the population will take a severe reduction in numbers. Not only is this year’s pupping season a disaster, but malnourished females may have lower birth rates in years to come.
In speaking to a marine mammal biologist the other day, she said that she had not heard of any similar troubles with our Stellar sea lions this year. Since the famine seems to be at the California coast, one would not expect the sea lions here to experience similar problems. However, when the top predators in the ocean are starving, humans should become very concerned. Not only is this crisis an expression of trouble in the ocean food web, the changing of ocean currents affects large scale weather patterns. This is one example of climate change at work; how it manifests itself from one year to the next is not always predictable.
With the start of the tourist season this month, I will be telling people about the Stellar sea lions around Kodiak. I will often be thinking about those starving pups in California. I made a small donation to feed them some fish smoothie. If you feel like pitching in or want to read more about this sea lion crisis, visit (http://www.marinemammalcenter.org/about-us/News-Room/2015-news-archives/sea-lion-crisis.html).