Marine dead zones are places where nearly all life has disappeared from the ocean ecosystems and they are as every bit as scary as they sound. They occur where intensive feedlot salmon production goes beyond what our oceans can bare. With too many fish in a particular area, levels of dissolved oxygen in the water decrease and the surrounding marine life suffer.
A clear example of this occurred in Macquarie Harbor on the west coast of lutruwita/Tasmania. Intensive, profit-driven pressure to produce more and more salmon led to extreme decreases in dissolved oxygen, leaving the dead zones on the seafloor beneath salmon pens adjacent to the Wilderness World Heritage Area. Ordinarily rich and biodiverse waters, home to endangered species like the Maugean Skate, became lifeless and barren.
Feedlot salmon producers have been asked to transparently inform consumers and the community about the minimum levels of dissolved oxygen in the water at each of their pens, but they have refused. The companies provide data on other oxygen measurements, but failing to give transparent data on what matters leaves consumers in the dark about the welfare of feedlot salmon and the surrounding ecosystem.
Would you eat farmed salmon if you knew it was creating marine dead zones?