THE CALIFORNIA SEA LION, ENDING

Sound production: a sea lion rookery is a very noisy area. The sea lion’s primary means of communication is vocalization. Vocalizations include barks, growls, and grunts. They are especially loud during the breeding season. Females use a specific vocalization signal during the mother/pup recognition sequence. This occurs when a female returns to the rookery after feeding to locate her pup. The female emits a loud trumpeting vocalization, which elicits a bleeping response from her pup. This exchange continues until mother and pup find each other. They also recognize each other by smell and by sight.

Food:

§ They are predators, obtaining all their food from the sea. They feed on more than 50 species of fish and cephalopods (squids and octopi), with their main ones being squids, octopi, hake, northern anchovy, opaleye and herring.

§ They are opportunistic predators of salmon, lamprey, and some bottom dwelling fishes. Those along the Washington coast take advantage of the winter run of steelhead salmon, waiting by the mouth of the Lake Washington drainage rivers and consume large quantities of salmon as they pass by on their way upstream.

§ Based on the records gained primarily at Sea World, we know that adult sea lions eat about 5-8% of their body weight daily, roughly around 15-40 pounds.

§ They probably use their sensitive whiskers/vibrissae to explore and locate food. They don’t chew the food, instead simply grabbing it and then swallowing the fish whole.

§ Scientists have found stones in the stomachs of sea lions. One specimen had more than 60 pounds in its stomach! No one knows the reason for this, although scientists have thought that perhaps this is to counteract the buoyancy caused by blubber, to stop irritation from intestinal parasites, or to assist in digestion.

Reproduction:

o Sea lions tend to breed on the same section of the beach year after year. They generally favor beaches on the windward side of islands.

o A male with an established territory breeds with an average of 16 females in one season.

o The gestation period is about 11 months. Most California sea lions are born in June. Females give birth to one pup each year.

o The pups are born on land. They are around 30 inches long and weigh more than 13 pounds. They are well developed, and within 30 minutes, they are able to shake, groom, scratch, and walk. They appear to be able to swim at birth, although their movements may not be well coordinated at first.

o The pups nurse for 6-12 months, or even longer with some individuals. The pups can and will eat fish after about 2 months in addition to nursing.

Longevity:

· They live for probably 15-25 years, although in zoological habitats, like Sea World, they have been known to live for more than 30 years.

· Predation is not a significant threat to a healthy adult sea lion. Killer whales and large sharks occasionally prey on weaker sea lions.

· Human interaction, as with many other marine mammals, is a significant threat to the health of the sea lions. Pollution (pesticides and heavy metals), fishing activity, and marine debris (fishing nets and packaging materials) can cause much damage to the sea lions.

· The Marine Mammal Protection Act of 1972 made it illegal to hunt or harass any marine mammal in U.S. waters. There are certain exceptions to this: native subsistence hunting, collecting, or temporarily restraining marine mammals for research, education, and public display, and the taking of a restricted number incidentally in the course of fishing operations.