Sharks are part of the food chain. They eat the seals and sea lions which eat the salmon. Kill all the sharks, watch the seal population explode and the fish populations plummet. How about this: how about staying out of shark-infested waters? Duh.
Yes.
I can. This species exists, and continues to exist, because it is an important part of the cycle of life.
Flies are nasty. But our world would not be the same without them. The ocean would not be the same without sharks.
What happens if you don't have algae eaters in your aquarium and you don't clean it by hand?
Uh, yes.
In this country we hunted top predators to extinction and took over that role ourselves.
Can't do the same in the oceans, so we need top predators for healthy sea life.
Swimming in the ocean is far less dangerous than the drive to get to the beach.