How People Have Affected Sea Lions

Sea lions are mammals that feed in the water, but spend a good amount of time on land. Large creatures that they are, the impact that sea lions have on their environment is large. What many people fail to realize, however, is that humans have a huge impact on the environment and population of sea lions.

There are many things that humans do - directly and indirectly - that can cause harm to sea lions.

Hunting and Harvesting

Killing of sea lions has been going on for thousands of years, whether it be for their meat, or their hide. They were originally hunted by various Native American tribes in California for meat, but began being hunted in the 1800s for their hides.

Today, sea lions are still shot by salmon fishermen because they spend time in salmon spawning grounds, even though they are usually eating parasites that cause harm to the salmon.


Studies done on female sea lions who miscarried their pups showed higher levels of a strong pesticide, known as DDT, than those who carried their pups to term. Along with pesticides, heavy metals are also a serious problem.

Litter from marine boats, such as netting and plastic containers, also pose serious threats to the sea lion population. Sea lions may become tangled in the netting, or ingest the litter, causing obstructions and other internal injuries. Becoming entangled in the plastic can lead to drowning, as sea lions are mammals that can only stay under water for a maximum of ten minutes.


Feeding wild animals can not only be an extreme danger to the person, but to the animals as well. Sea lions will frequent spots where they were previously fed by humans. This can lead to damage to docks and boats, but the sea lions can also get injured on boat motors, or by frightened humans. A sea lion encounter can be dangerous, and humans should be sure to keep their distance.

While the meat and hide of sea lions was found to be useful in the past, the dwindling number of sea lions caused them to become a protected population. In 1972, the Marine Mammal Protection Act has helped their population to grow 10% each year. Even with increasing numbers of sea lions, the human impact has been great.

The number of humans in natural environments is growing, causing more pollution, littering, and indirect harm, such as feeding. The more comfortable that sea lions become with humans, the more dangerous it will be to their species. Ensuring to keep a safe distance during a sea lion encounter is vital, both for your safety, and the safety of the sea lions.