The West Coast of the United States has experienced a marked increase in the number of California Sea Lion pups stranded on beaches across southern and central California during the first four months of 2015. The sight of distressed marine life along our shores is an emotive topic for those of us who enjoy spending time on the water. Most paddlers have a deep appreciation for the ocean and the marine life dependent on a healthy ecosystem in order to survive. As word of the strandings began to filter through the stand up paddling community in Southern California, SUP Examiner decided to look into the situation and report back to the paddling public.
This is the first installment in a three-part series examining California Sea Lions and the increased number of pup strandings in 2015.
The Life of a California Sea Lion
Like all marine mammals, California Sea Lions are protected under the Marine Mammals Protection Act. They can be found along a broad stretch of the western coast of North America from Canada to the central portion of Mexico. According to National Geographic, colonies of the intrepid pinnipeds are also located near the Galápagos Islands off the coast of Ecuador. Pinniped(s) refers to all flipper footed marine mammals and their adaptation of flippers makes them highly effective swimmers. California Sea Lions have been documented as the fastest swimmers of all pinnipeds, capable of attaining speeds of 25 mph (40 kph). They also have the ability to regulate their heart rate when diving deep which enables them to remain underwater for roughly 10 minutes at a time. In addition to their speed and agility in the water, California Sea Lions are able to rotate their rear flippers into a forward position giving them the ability to mimic a walking motion on land compared to the lumbering, belly rolling of a seal. Another distinguishing characteristic of the California Sea Lions are their external ears – a trait which seals do not posses.
Adult California Sea Lions are between 7-8 ft (2-2.4 m) long and weigh up to 800 lbs (363 kg) for males and 5-6 ft (1.5-1.8 m) and approximately 250 lbs (113 kg) for females. California Sea Lions are carnivores and known to be opportunistic predators feeding on a diet of oily fish such as hake, market squid, mackerel, sardines and anchovies, among other prey. Adult animals are fully independent and not socially dependent on others for food or interaction. When observing groups of California Sea Lions in the wild, the fact some may be clustered together is reportedly no different than if one were to observe a group of people sitting together at a bus stop. They just happen to be sitting together at that moment in time.
California Sea Lions are a common sight for stand up paddlers along the western coast of North America. Regularly spotted in marinas sleeping on docks or untended boats, they may at times appear to interact with paddlers. Although they have a playful demeanor, paddlers should respect the sea lion’s personal space and never attempt to touch a sea lion. California Sea Lions are unpredictable and may become aggressive. They have a sharp set of teeth and may bite if they feel the need to defend themselves or their young. If that isn’t enough of a deterrent, there is also a $10,000 fine for unlawful interaction with marine mammals in the United States.
Groups of California Sea Lions are known interchangeably as either “colonies” or “rookeries”. The [U.S.] National Marine Fisheries Service estimates the current total population to be approximately 300,000 animals, with a projected annual increase of 5.4%. Within the United States, the California Sea Lion’s breeding rookeries are in the Channel Islands – primarily San Miguel, San Nicolas, Santa Barbara and San Clemente. The species typically gives birth to their young in June and pups remain with their mothers for approximately 11 months before they are considered to be 100% independent.
Broadly speaking, the population is not believed to be in jeopardy and the species is not listed as “endangered”, “threatened” or “depleted” under the Endangered Species Act and Marine Mammal Protection Act. Overall, the population is believed to be increasing, however, there have been periods where the number of California Sea Lions has declined as a result of El Niño events, disease and limited availability of prey due to the ever-changing dynamics in the ocean.
Part Two of this series will take a look at the likely causes of the California Sea Lion pup strandings.