A declining cisco population has consequences for aquatic habitat and other species in the food chain.
Lake stressors such as increasing water temperatures and nutrient runoff present challenges for many native Minnesota species to thrive and survive. One essential species is cisco, often referred to as “tullibee,” which provide an integral source of food for walleye, northern pike, muskellunge, loons and many other native species. Cisco are especially sensitive to changes in their environment and need cold, well-oxygenated water to survive. Depletion of oxygen caused by longer periods of ice free, open-water and nutrient runoff force cisco to move into warmer surface waters where they can experience mortality from thermal stress.
The Department of Natural Resources (DNR), in partnership with the Pollution Control Agency, champion the monitoring of Sentinel Lake. The long-term program monitors habitat to learn how changing conditions affect pelagic cold-water fish like cisco.
The DNR is stepping up by helping landowners who own forested land in cisco lake watersheds. Minnesota’s coldwater fish face declines in habitat caused by rising temperatures. Actions that reduce nutrient runoff and maintain oxygen levels in deep, cold lake waters will help reduce stress on fish populations like cisco and are more important than ever.