That’s not what property means tho. If you discover a value on your property you didn’t know was there, it’s still yours. That’s why when people discover oil on their property they end up millionaires selling it to others. If a gold vein is discovered under your property, it’s yours, in theory.
Currently we think of property in two dimensions, but we need to come to think of property in three.
You own a defined space, with the right to dispose of values on that space and keep others out. The water flowing through that space is a condition of that property, which you may dispose of as you like while it’s on your property, as long as you’re not materially damaging the property of the person next to you for whom flowing water is also a property contingent on it flowing through yours first. Just as the guy upstream from you shouldn’t pollute water coming into your space.
I think of fish ranging through as a similar quality: a condition of that property, which is diminished is harm to your property.
But suppose we were in space, with asteroids flying through our property continually and we built an asteroid catching facility to mine metals. Asteroids flowing through is why we bought that space, and without that we would never have built our facility. So that, if anyone bought space next to us, “up-asteroid-stream” as it were, and blocked all incoming asteroids, they’ve clearly harmed us materially. Asteroids flowing through are a property of that property.
And suppose we discover some invisible black hole on the property that ends up being fabulously valuable. We’re free to sell it–tho we have no mixed our labor with it.