This graph shows the Male Seal births for over 40 years, this causes the population to rise until they hit carrying capacity, then seals start dying causing the population to decrease.
This picture show the seals who are migrating from the coasts of California to Alaska, this is an example of immigration because they are immigrating from one place to another, this causes the seal population to rise in the area that they are migrating to. Some of the seals are emigrating from California and that can reduce the population in that area.
There are a few density-dependent factors that limit the seal population one of which is predators, exclusively sharks, sharks cause many seal deaths each year. Another factor that causes many seal deaths are diseases and parasites, which may attack the heart, lungs, blood vessels, stomach, intestines, nasal cavities, and skin.
Two density- independent factors that affect the seal population, would be hurricanes because they can kill seals as well as relocate seals away from resources needed, or other seals, which would mean they would not be able to reproduce lowering the population. Another factor would be habitat disruption from oil spills, because the oil has the ability to kill seals, as well as limit the resources that a seal would need.
Limited resources can cause the seal population to have a logistical growth because when there are not many seals there will be more resources, such as octupuses, or penguins, but as the seal population rises the resources are limited and the predators increase, because they now have food. The growth of the seal population slows down, and stops once it reaches carrying capacity.