The Oceans - a common(s) resource ?

Thanks to Richard Allaway for the link to this resource.
It would be useful for Year 7s who want a particularly good argument for not serving fish in their menu that is 'good for the world'.
It talks about the depletion of fish stocks in the world's oceans, and the link with an idea called the 'tragedy of the Commons'

IN 1968 an American ecologist, Garrett Hardin, published an article entitled “The Tragedy of the Commons”. He argued that when a resource is held jointly, it is in individuals’ self-interest to deplete it, so people will tend to undermine their collective long-term interest by over-exploiting rather than protecting that asset. Such a tragedy is now unfolding, causing serious damage to a resource that covers almost half the surface of the Earth.

Image: Sally Parkinson