Yes, Sharks are that important. There are many ways in which Sharks keep the ecosystem in a balance. Being top predator of the oceans, they keep prey in check which in turn keeps reefs etc healthy and therefore the oceans stay healthy. Overfishing of sharks will affect everything. If the sharks go, the oceans will get affected and so will the Earth.
We have been put on this planet to take care of it. All of creation was given to us to protect and nurture and use as we needed. We have abused that privilege and our future generations will have to reap the consequences unless we change things today.
World Oceans Day