California sea lions and Steller sea lions are the two most common sea lions on Vancouver Island. It is mostly male California sea lions that spend from September to May here since the females usually stay all year in California and Oregon. The California males can weigh up to 400kg (900lbs) compared to the Steller males max weight of 2500 lbs (1120 kg). The female Stellers can be closer to the male California sea lion with a max up to 450 kg (1000 lbs).
California sea lions are usually a dark brown/blackish color compared to the Steller sea lions which are a often a light tan or reddish brown color. They are often mixed together during winter months and it should be fairly easy to identify the smaller darker California sea lions. During summer months most California sea lions head down to the rookeries in California to mate.
Vancouver Island numbers
California Sea Lions are mostly seen in the southern half of Vancouver Island though will go as far as southern Alaska. The number of California Sea lions wintering in BC have been increasing since the 1970s along with the increased numbers in California and Mexico. The numbers along the US coast line have gone from an estimated 50,000 in 1970 to 300,000 today. About 3-4000 make their way to Vancouver Island. Read more about the increased sea lion population here…
From May to August most males have returned to the rookeries in California to mate. Females will gather in groups before the mating begins and will mount each other along with males. There is a 12-month reproductive cycle which includes 3 month period for the egg to get fertilized and a 9 month gestation period. Mothers will stay with the pups for the first 10 days before going to hunt for food.
Numbers of pups being born every year have been steadily increasing since the 1970s to a possible over population. Around 65,000 pups are born yearly along the coast and most stay in nurseries until they are able to go hunting with the mother.
Prey for the California sea lion includes salmon, hake, herring, pilchards, anchovies, squid, small sharks, and rock fish. Their hunting trips at sea can last two weeks and they can dive up to 274 meters (900 ft), though shallower dives are more common. They will sometimes feed around dolphins, porpoises, and even birds while attacking the bait fish. About 35% of their diet is herring and they consume about 3000 tonnes annually around Vancouver Island. Salmon make up about 10% of their diet though for some salmon make a great percentage. At least 600 tonnes are taken annually. Sea lions have become a nuisance to herring and salmon fisherman as well as around salmon and trout hatcheries and river mouths. One sea lion can eat 10,000 salmon fry in a night’s feeding. DFO in Canada has spent large amounts of money and time trying to deter them from entering the rivers without much success.