Healthy adult sea lions do not have many predators. However, great white sharks and killer whales consume them from time to time. Young sea lions are at risk to killer whales, salmon sharks, sleeper sharks and great white sharks. Additionally, while they currently receive legal protection, many sea lions have been killed by humans.
Stellar sea lion pups experience increased mortality from predators. Transient killer whales are the most important factor in this increase. Because the young sea lion pups are more predictable than the adults are, the killer whales are able to concentrate their hunting time near the shore, where the sea lion pups spend a lot of time.
Sea lions are large animals, the largest of which reach up to 770 pounds in weight. The killer whale's caloric needs indicate that they must eat two or three sea lions pups per day, or a single adult sea lion every few days. Human poaching is another problem for sea lions. Many fishermen shoot the sea lions, mistakenly believing that they are affecting salmon populations. However, according to Sea World Parks & Entertainment, while they do eat some salmon, sea lions also benefit salmon populations by eating some of their parasites.