* Prey animals, such as seals, sea lions, fish, and squid
* Predators, such as killer whales and humans
* Competitors, such as other sharks and marine mammals
* Parasites, such as tapeworms and roundworms
* Commensals, such as remoras and pilot fish
Non-living factors:
* Water temperature
* Salinity
* pH
* Depth
* Light levels
* Oxygen levels
* Currents
* Waves
* Tides
* Bottom topography
* Human activities, such as fishing, pollution, and climate change