Most California sea lions spend the summer off California and Mexico mating. By September the adult and sub-adult sea lions are in or on the way to their winter home and they come as far north as Vancouver Island. Prior to the 1960s there were just a few coming here. By the early 80s there were 1500 coming up here and by 1984 there were close to 4,500. Since that time there are about 3000 making their way up.
Overpopulation of California Sea lions:
California sea lion are listed as “least concern” due to its large and fast growing population size by the International Union for Conservation of Nature. In 1970 there were close to 50,000 California sea lions in the US (does not include Mexico and other reginos) and now by estimation there are close to 300,000. Footnote
Sea lions have become a threat in both US and Vancouver Island rivers feeding on salmon before they head up the rivers and eating salmon fry in the rivers and at the mouth of the rivers before they head out to sea. The warmer California ocean conditions are pushing larger masses of sea lions to the northwest in search of food.