Lobster pool?

Looking at satellite imagery the other day, I saw this large enclosure between two islands just S of our house.
On the way to the shops for our biweekly shop, we stopped and walked out to it. An impressive edifice, especially when you consider it has probalby been there for many years being covered by the sea twice a day and not a drop of cement in it. I reckon you might spend as much time looking for your lobsters in this pool as you did catching them in the first place!
Another example of somewhere close to home I had never been too.....