In inconspicuous sheds in Fredrikstad in south east Norway, two gigantic tanks are foreshadowing a salmon farming industry that is increasingly tempted to migrate to land-based facilities, which until now has been the preserve of freshwater fish. By raising the salmon on land, the industry is attempting to rid itself of the issues around the tradional submerged cages that made it controversial: costly mass escapes, harmful sea lice and the chemical treatments to get rid of them, as well as mass sludge deposits on the seabed below salmon farms. IMAGES AND SOUNDBITES