I still believe keeping salmon farms, no matter if caged or enclosed, is not as "sustainable and healthy" as we are led to believe.
Whilst the content of salmon feed has seen a reduction from around 70% fish meal to about 35%, thus reducing the ridiculous situation of needing up to 8kg of wild caught fish to produce 1kg of farmed fish, they are now bulking feed with terrestrial based plants and oil.
That brings its own issues of fertilisers, deforestation for palm and canola oil (fish oil substitute for pellets) and production of crops not directly for human consumption.
This also introduces non marine based proteins and toxins into the marine food chain in the way of waste and uneaten pellets.
We have severe environmental issues in Chile, Tasmania, Norway, Russia, Ireland and Scotland associated with salmon farming. Is it not about time this industry was called into account rather than having millions thrown at it by governments?