- Wed Feb 03, 2021 10:17 pm
Check out this sentence from paragraph 3: "For the ten species of fish most commonly farmed, an average of 1.9 kilograms of wild fish is required for every kilogram of fish produced." If it takes 1.9 kilograms of wild fish to produce 1 kilogram of farmed fish (the farmed fish are eating the wild fish) then farming fish ultimately results in a net decrease of fish.
Think of it this way. All the fish in the world are a potential food source, whether they are farmed or wild caught. If we just catch the wild fish, we can catch 1.9 kilograms and all of that would be food for humans. But if we farm fish, we can produce 1 kilogram of farmed fish as food for humans, but only by using 1.9 kilograms of wild fish to feed the farmed fish. In both scenarios, we would be consuming the same amount of wild fish. But in the all wild-caught example we've got 1.9 kilograms of fish to feed to humans and in the farmed fish example we've only got 1 kilogram of fish to feed to humans. Thus, in the farmed fish scenario, to meet whatever demand humans have for fish as a food source, would require consuming more wild fish than would just using wild fish only as a food source.
Farming fish is basically taking 1.9 kg of fish and turning it into 1 kg of fish.
Food produced by the process of farming fish: 1 kg
Food consumed by the process of farming fish: 1.9 kg
1 kg - 1.9 kg = -0.9 kg
That -0.9 is the net amount of fish produced as a food source for humans from the process of farming fish. That's a net decrease!
Hope this helps!