Closed containment salmon farms require an energy input for the circulation of fresh water and dissolved oxygen as well the removal of waste. In the media, the salmon farming industry claims this energy use creates an “extensive” environmental footprint. However, what they leave out of the equation is that while net-cages use tidal power to perform circulation and waste removal functions (at no cost to the industry) this practice in the open ocean creates a significant environmental footprint.
In assessing the overall sustainability of net-cages vs. closed containment, we must consider all environmental impacts and their potential solutions in order to determine the most responsible technology for salmon aquaculture.
The main environmental concerns associated with open net-cage aquaculture are: sea lice and disease transfer to wild salmon; pesticides and antibiotics and their impact on ecosystem health; chemical pollution; escapes and invasive alien species; marine mammal deaths; waste build-up and contamination of the ocean floor; the use of wild fish for feed; and marine debris.
Closed containment technology reduces or eliminates most of the environmental impacts of net-cage farming, with energy use and feed impacts the remaining concerns. However, solutions are on the horizon to address these concerns as the technology continues to mature.
In a world working towards green energy solutions and sustainable industry, net-cage salmon farming is a dead-end technology. Independent scientists, concerned citizens, First Nations, fishermen, conservationists, wilderness tourism businesses and coastal communities that depend on healthy oceans agree – the weight of scientific evidence is clear and it’s time to get net-cage farmed salmon into closed containment.