T7

• fish farming pros: more regular than fishing, reduces over fishing (helps maintain biodiversity), many of the fish are products of selective breeding
• fish farming cons: parasites can be spread easily, greater risk of disease, pollution of uneaten food and feces sink in the tank
• eutrophication 1: nitrates from fertiliser are washed into lakes and streams
• eutrophication 2: an algae bloom grows on the surface
• eutrophication 3: algal bloom block sunlight
• eutrophication 4: plants die on the bottom of the lake
• eutrophication 5: bacteria decompose dead plants using up oxygen when respiring
• eutrophication 6: lack of oxygen means animals suffocate and die