Sea Lion Pups May Be Starving Because Consumers Want Pizza and Fish Oil

Sea lion pups along the California coast aren’t getting the nourishment they need. For a number of years, skinny, malnourished pups have been washing up onto beaches. It’s a phenomenon that puzzled scientists for quite some time.

Now researchers believe they finally know why the pups are struggling to live. It’s about diminishing food quality and to some extent, it could be our fault.

According to a new study, nursing sea lions can’t find enough of the right kind of fish to eat anymore. Mother sea lions require sufficient supplies of high quality, high calorie, energy-dense fish like sardines and anchovies. Instead, they end up eating what they can find — lean, low calorie fish like squid and rockfish.


While those fish are dandy for dieting humans, they don’t offer anywhere near the level of nutritional support a nursing sea lion mother needs. Even though mother sea lions can usually find all the rockfish and squid they want, it isn’t enough. That diet doesn’t enable her to offer her pups high quality milk. It’s like feeding your kid a cupcake every day when he really needs to be eating his broccoli and carrots.

People Like Oily Fish. So Do Sea Lions.

The reasons for the shortage of these specific kinds of fish are complicated. These days, humans want foods that will give us an omega-3 fatty acid boost. Oily fish are one good natural source. Salmon, mackerel, anchovies and sardines pack a fishy nutritional wallop that’s hard to deny.

In addition, don’t forget that people really like eating anchovies. We put them on millions of pizzas every year. We use them as an ingredient for Caesar salad dressing. The same goes for sardines. Both fish are often included as ingredients in recipes to increase the “umami” or savoriness of a dish. Pet foods add oily fish to their products to jack up the omega-3 content, because that’s what consumers want.



That’s all well and good, but there’s a tipping point. Humans can’t have all the fish in the sea. Apparently, we may be taking more than our fair share. It’s possible we’re verging on overfishing sardines and anchovies, leaving too few of them to feed their natural predators — like mother sea lions.

“For human consumption, highly oily fish may actually be less desirable to consumers,” the study’s lead author, Sam McClatchie, told Discovery News. “In contrast, for predators with high energy demands, such as nursing female sea lions, eating fish with higher energy density due to higher content of calories and fats provides a more effective way to meet their nutritional demands.”

Are Environmental Causes Really to Blame?

To be clear, this study found uncertainty as to the true cause of the fish shortage. Overfishing may play a part, but environmental problems may be even more to blame.

“Sardine and anchovy populations both show large inter-annual variability that is environmentally driven and prior to any fishing,” McClatchie told Discovery News.


Researchers discovered that during years in which an El Nino affects the California coast, sea lion pups are notably thinner. More of them die than is typical in other years. However, they say El Nino years aren’t solely the problem either.

The overall population of sea lions has increased thanks to conservation efforts. That means there are more mother sea lions trying to find quality food, while there’s less of that food to go around. The result of that equation is all too easy to predict.

Whatever the primary cause, this problem isn’t going away any time soon. Researchers know they’ll see malnourished and starving sea lion pups for years to come. Marine rescue centers are already taxed almost to the breaking point. It’s a sad state of affairs with no obvious solution.

Maybe pizzas with no anchovies and vegan omega-3 sources are one way to start.

Photo credit: Thinkstock


Sue H
Sue Habout a year ago


Christine Stewart
Christine Stewartabout a year ago

poor little baby seals...

Ruth S
Ruth Sabout a year ago

I don't like Salmon, mackerel, anchovies or sardines. So let the seals have them. Thanks.

Clare O'Beara
Clare O'Bearaabout a year ago

I do not eat anchovies

Clare O'Beara
Clare O'Bearaabout a year ago


Clare O'Beara
Clare O'Bearaabout a year ago


Lorraine A
Lorraine Andersenabout a year ago

The whales are also starving. We have fished the ocean to near extinction and left nothing for the animals to eat. We need to change our ways and soon or we will be the the next ones starving!

Chad A
Chad Aabout a year ago

Thank you.

JoAnn P
JoAnn Parisabout a year ago

Grrr ...

Ann B
Ann Babout a year ago

this can be fixed SO lets do it---save them