This is a central issue to Libertarianism, when something belongs to someone then that property has to be taken care off and if harmed then there is a victim. But if no one one owns something then there isn’t really a reason to take care of it or to have a victim if the property is harmed. If the oceans were owned by someone then they would be taken better are off. This also applies to parenting where I give my kids certain special toys that are theirs and they can make an automatic claim on if another kid is playing with them. This will teach them about the importance of taking care of their own stuff and respecting each others private property.
The MISES Institutes does a phenomenal article on private property and how important it is. Private Property Is the Essence of Liberty – Ron Paul