Salmon are threatened mostly by fishing, both commercial and recreational. According to the FAO, since 1990, the global capture of salmon was estimated at 1 million tonnes per year.
When it comes to farmed animals, the only land farmed animals are taken into consideration, however, aquatic animals can suffer in farming too. Salmon is one of the most used species of fish in farming. They are kept in sea cages that are made out of steel or plastic.
Salmon are caught by a wide variety of methods, the most common are, of course, nets. Other methods are gillnets - “walls of stationary or drifting netting that are almost invisible to fish.”
“Set, drift, and trammel gillnets use different configurations of floats and weights to suspend the netting more or less vertically. Encircling gillnets are set in shallow waters, and noise or another means is used to entangle the fish in the netting. Fix gillnets are stretched between two or more stakes that are driven into the seabed in the intertidal zone.
Gillnets can accidentally catch vulnerable ocean animals like sea turtles, marine mammals, and sharks. These impacts can be reduced by setting the gillnets deeper in the water column to allow room for animals to swim over and adding gear like pingers, which warn passing marine mammals.”
Another method of fishing salmon is trolling lines. “Trolling lines lure fish with moving fishing lines with baited hooks. Several trolling lines are often towed at the same time, and equipment called outriggers keeps the lines away from the boat’s wake. The lines are hauled in by hand or mechanically using small winches. Trolling lines are used to catch a variety of species such as mackerel, rockfish, salmon, and tuna. This fishing method has low catch of unwanted marine life.”
As for the farming methods, salmon are kept in pens. There are more hundreds of marine and freshwater species of aquatic animals that are farmed at present. All of the seafood comes from farming, not wild, except for amateur fishing, of course.
“Pens are structures that hold farmed fish in open water as they grow. They’re made with wooden, mesh, or net screens, which allow water to flow freely through them. Net pens can be in marine waters to farm species such as salmon and trout or freshwater to farm species such as tilapia and trout. Types include pens, which are fixed to the bottom in shallow waters. Net pens are enclosed on the bottom and sides. Submersible net pens are fully enclosed and submerged, usually in offshore marine waters.”
Read more: Fishing and Farming Methods