The approval means while Huon Aquaculture and Petuna have to...

The approval means while Huon Aquaculture and Petuna have to maintain stocking levels under 13 tonnes per hectare, Tassal can run more than double that amount - up to 28 tonnes per hectare.

The article linked clarifies how Tassal have somewhat bypassed the production cap. Huon seems to be chucking a fit given that Tassal sided with the government. They also are complaining about preferential treatment which I think is the core reason for this case.

"It beggars belief that special treatment appears to be given to Tassal at every turn and this is yet another example," they said.

"It is clear that Huon has been deliberately been kept uninformed about the project."