Cisco are sometimes called the "canaries of cold water." They do not tolerate warm water or low oxygen levels and have declined in, or disappeared from, over 20 percent of their native lakes in Michigan. Development and other land use changes can lead to increases in the nutrient phosphorus. Increased nutrient levels accelerate plant and algae growth, which in turn drives greater decomposition below the thermocline of stratified lakes, depleting oxygen required for cisco to thrive. Inland lakes that do retain high water quality are often stocked with trout, which also require cold oxygenated water, or other gamefish. Stocking predators or competitors is also recognized as the cause of cisco decline in some inland lakes.