The “Tragedy of the Commons” is a straw man fallacy. The commons have historically always been collectively managed by the villagers grazing their animals on it. What you should be complaining about is the tragedy of an unmanaged (or in other words unregulated) commons.

http://mrzine.monthlyreview.org/2008/angus250808.html

That the oceans, a common resource, are not sufficiently regulated, suggests we need better global governance.