If we continue on depleting the oceans, then the human population will not be able to survive. A report from the Independent Panel on the State of our Oceans says that the declining vitality of the oceans is becoming our biggest problem. Even though we are getting better at catching fish, it is becoming harder to find the fish because we consume so much fish. We have also disturbed the sea bed and destroyed habitats that help the productivity of the oceans. We have also poured chemicals and pesticides into the oceans. The ocean temperature has risen because of us, which has also disturbed the productivity to replenish itself. In order to survive, we have to use the oceans sustainably and nurse it back to health by setting aside marine sanctuaries where no human activity is allowed. At least one quarter of the ocean needs to be protected to ensure our survival.
Lots of people live near the oceans and use them for recreation, getting food, finding necessary goods, etc. Setting aside one quarter of the oceans for marine sanctuaries would displace lots of people. These people would have to pick up their lives and start over somewhere else. Many people might not be able to do this because they do not have the resources to do so. For example, if we were to set aside the area were Somalia, all those people would not be able to move because they do not have the resources to do so. Somalia is one of the poorest countries in the world and displacing all those people would also disrupt their government. They don’t have the resources to support a lot of their people much less support the movement of a lot of people to make room for an aquatic sanctuary. Since a lot of people in Somalia are suffering from poverty, they wouldn’t be able to relocate their lives.
http://www.guardian.co.uk/environment/2011/nov/15/seas-sustainable