Where Is It Safe to Farm Salmon? On Shore!
When one hears about farming fish, you think about the net-pen rearing of Atlantic salmon or trout — which we know pose threats to our resident and migratory salmon. Cramming thousands of salmon into a small pen creates a continuous, concentrated plume of fish excrement for the local environment. This plume pollutes the environment, and since many pens are built in inlets to reduce wave action, the effluent concentrates in these areas.
The collapse of the net pens off Cyprus Island in 2017, moreover, demonstrated how the largest net pen operators can fail to comply with existing regulations, which should cause all of us to closely reconsider this type of farming.
Thankfully, Canada is addressing these problems by phasing out pen-rearing of salmonids (including salmon and trout) and encouraging a whole new form of aquaculture: Recirculating Aquaculture Systems (RAS). RAS are land-based, closed systems which eliminate the problems and risks of net pens. The fish are raised in tanks, and the water goes through several stages of treatment before recycling back into the closed system. No effluents are released, and potential disease is contained.
Last year, Canada’s Prime Minister Justin Trudeau committed to a transition from net pens in coastal waters to RAS systems by 2025. British Columbia is carrying out this national policy locally, detailed in this excellent article in RASTech Magazine: Canada Begins Transition for Salmon Net Pen Farms. Check it out!
Our coho have a perilous journey from the Chittenden Locks to the Issaquah Salmon Hatchery — and researchers at the University of Washington, Tacoma and Washington State University, Puyallup have identified the chemical responsible for mass pre-spawning deaths of adult returning coho in our urban streams. 
One of the miraculous facets of a Pacific salmon’s life is its death. All Pacific salmon die after they spawn. In doing so, they enrich their home stream with their harvest of years of nutrition on the high seas. This chinook will feed the local ecosystem, and perhaps even its progeny when they emerge from the gravel in 4 months time. 
King County has funded a new study to examine how wastewater pollutants from the county impact salmon and orcas. Pollutants from our roads and drains end up in stormwater runoff — and now scientists are looking for more information on how these pollutants impact juvenile salmon. 
A plan to divert water from the Sacramento-San Joaquin River Delta jeopardizes already endangered salmon populations. NOAA Fisheries biologists and environmental groups are fighting to protect the water source and the fish who call the threatened delta home. 
