The California sea lion (Zalophus californianus) is a common site along the coast of North America from southeast Alaska to central Mexico, including the Gulf of California. Population estimates within that range indicate that there may be more than 350,000 California sea lions along the coast of North America. Due in no small part to the Marine Mammal Protection Act of 1972, the population of California sea lions along the Pacific coast of the United States are at or near carrying capacity, an ecological term defining the maximum population size of a species that can supported within its ecosystem.
The increasing number of malnourished or sick sea lion pups seen along the coast of southern California and other areas may be an indication of the overall population being at carrying capacity. Populations of organisms don’t simply and abruptly stop reproducing when reaching carrying capacity. Rather, populations tend to oscillate around that limit alternately exceeding, and then declining to levels below carrying capacity. When the population overshoots the carrying capacity, the ability of the individuals in the population to find necessary resources for survival is limited and the mortality rate increases. The youngest members of the population are often the ones that bear the brunt of this lack of resources. As a result, one would expect to see increased numbers of malnourished and sick sea lion pups on local beaches when the population is greater than the resources available to support it.
The young sea lion seen in today’s photo may have been suffering from those conditions, although I have no idea of what its condition actually was. I found this young sea lion laying on the beach at Leo Carrillo State Park in 2007. While there were no outward signs of injuries, it certainly wasn’t acting in a way that one would expect of a healthy, young sea lion. It lay on the sand in the sun, nearly motionless. I could tell that it was alive by the movement of its nostrils while breathing, but otherwise this animal was nearly immobile. Adding to the somberness of the scene, lifeguards had placed yellow caution tape around the animal to keep people from getting too close. This was in accordance with both the Marine Mammal Protection Act, and the desire to prevent people for harassing the animal, and possibly getting bitten.
A good friend of mine, Bob Perry, is absolutely infatuated by California sea lions. While I can’t compete with his enthusiasm about them, being able to see them “flying” underwater is an incredible experience I’ve had while diving, and will always seek the chance to see them zooming around like mad things, seemingly effortlessly.
Today’s photo was taken with a Canon EF100-400 mm f/4.5-5.6L IS lens zoomed to 400 mm on a Canon EOS 10D. The exposure was set to 1/500 sec at f/8.0 and ISO 100.