Fishing on Land

There is a report (http://www.guardian.co.uk/environment/2012/dec/17/scottish-salmon-fishing?INTCMP=SRCH) that a company called Fishfrom is considering farming Scottish salmon in  large, hanger-like constructions divorced from direct contact with the sea. The fish would be reared on cultivated Ragworm and, it is claimed, the technique could avoid many of the current problems of salmon fish pens (Sea lice infections, interrring with wild salmon viability, decimation of certain salmon food species etc). The 'fish factories' would recycle most of their water and use a combination of solar and hydro-electric power. It is claimed that many of the up-market UK retailers would be attracted to its product. I suspect that this might well be the shape of things to come but I wonder what hidden problems might arise in the future? Cultivating Ragworm and Salmon at high densities always seem to attract difficulties. Fish welfare is likely to be easier to monitor in such a system.