All of my work is really derived from other people's data. Those folks who are in the field—either at the Freshwater Institute or in other settings—actually have the experience, as to how many fish you can keep alive in a cubic metre of water and how to actually grow them in healthy conditions. Unfortunately, I don't have any direct knowledge of that. Ultimately, my impression is that we can push animals pretty hard into higher densities. It just raises the stakes, in terms of the vulnerability of systems to power outages and to failures of systems.
I don't know how comfortable different strains of Atlantic salmon might be at very high densities, but basic biological principles would suggest that at higher densities your system is going to be more vulnerable to minor interruptions. If the electricity goes off and your backup generator doesn't kick on, and you've got 70 kilos of biomass in the water as opposed to 20 kilos of biomass, you're going to have a problem faster.