Rough fish are commonly found in eutrophic lakes. Mesotrophic lakes lie between the oligotrophic and eutrophic stages. Devoid of oxygen in late summer, their hypolimnions limit cold water fish and cause phosphorus cycling from sediments. People can accelerate the eutrophication process by allowing nutrients from agriculture, lawn fertilizers, streets, septic systems, and urban storm drains to enter lakes. In nutrient-poor areas, the aging process may lead instead to dystrophic and bog lakes which are highly colored, acid, and not as productive as eutrophic lakes.
Researchers use various methods to calculate the trophic state of lakes.
The trophic states associated with these three measures are shown in Table 4.