The species I chose is salmon.  Ocean wise recommended for consumers are the Atlantic salmon (blue circle brand only) from Norway – Kvaroy and Selsoyvik farms only.  Kvarøy and Selsøyvik reported no escaped salmon for over 10 years. The use of lumpsucker fish to control sea lice necessitates the use of small-mesh netting. This reduces the likelihood of escapes. This salmon is farmed by an open net pen.  Open net pens allow discharge to flow into the environment and have the potential to cause many negative habitat impacts. However, the Kvarøy and Selsøyvik farms are located in open coastal areas instead of fjords where there is less water circulation. .  Along with the Atlantic salmon worldwide which is farmed by the recirculating aquaculture system.  Source of stock is domesticated broodstock for the vast majority of RAS farms. Therefore wild populations are not depleted to source the aquaculture operations.  The contained nature of RAS allows for close control and prevention of potential disease or parasite outbreaks.  About 90-99% of water is typically recirculated after filtration and waste treatment.

Ocean wise did not recommend any of the Atlantic salmon that come from British Columbia, Atlantic Canada, Maine, US, Norway, Scotland, Chile, Faroe Islands, and Worldwide.  All of these salmon are farmed by open net pen.  When open net pen farming is carelessly done it produces waste products (faeces and feed) from the farmed salmon in the pens and is released directly into the surrounding water and settles to the sea floor. These wastes can change the chemical make-up and biological diversity of the seabed around the pens.

Salmon farming comes with issues and concerns as well as advantages.  One issue being the way it is farmed.  Open net-cage salmon farms are a serious threat to the balance of life on the coast, and to wild salmon in particular.  Waste, chemicals, disease, and parasites from the farms pass through the mesh and pollute the surrounding water and seabed. Especially harmful are the sea lice who attach to wild juvenile salmon on their migration out to sea. Too many sea lice can kill the young wild salmon.  Not only is the salmon polluting the waters with their waste they are killing their own species.  Storms, accidents and predators can tear the nets allowing the farmed fish to escape.   Advantages of these methods however, is that it is efficient.  You catch great amounts of salmon to sell and this is ultimately beneficial to our economy.   Although, what’s more important our oceans and the species or our economy?

Sources:

https://livingoceans.org/initiatives/salmon-farming/issues/environmental-impacts-open-net-pen-salmon-farms-benefit-the-ocean

https://seafood.ocean.org/seafood/type/salmon-atlantic/

https://livingoceans.org/initiatives/salmon-farming