There is a place for this type of farming in our society as it has been several decades since there have been enough fish in the sea to meet, on a sustainable basis, the growing worldwide demand for seafood. Approximately half the world's wild fisheries have been exhausted by over-fishing. In the north Atlantic, one of the most depleted oceans, populations of popular fish such as cod, flounder, haddock, hake and tuna are one sixth of what they were a century ago.