During October, Minnesota Department of Natural Resources’ (DNR) fisheries crews will be busy harvesting and stocking walleye fingerlings all across the state. In Otter Tail County, the fisheries crew, based in Fergus Falls, will harvest and stock walleye fingerlings into 11 lakes. These lakes include Donalds, Marion, Little McDonald, Seven, Six, Stalker, Pebble, Hoot, Wright, Bass and Loon. Approximately 4,100 pounds of walleye fingerlings will be stocked into these lakes this fall.
Walleye fingerlings are produced in DNR rearing ponds. The rearing ponds are shallow, fertile water basins that the DNR leases access rights to. Area DNR fisheries crews take newly hatched walleye fry from the Walker Lake fish hatchery on the Dead River in the spring and stock them into these ponds. The fry are then allowed to feed and grow on their own over the summer months. The fry will feed on natural foods that are produced in the ponds including zooplankton, a variety of invertebrates, and minnows. The mosquito-sized fry grow over the summer into 4 to 8-inch walleye fingerlings. Once stocked, fingerlings will grow approximately 3 inches per year. Walleye will be about 14 inches in length or weigh about a pound at 4 years old.
Area fisheries crews set trap nets into the rearing ponds to capture the walleye fingerlings. Several times a week the crews launch boats to collect fingerlings from the traps. The fingerlings are weighed and transferred to a transport truck. The fingerlings are then released into one of the lakes on the stocking list. This process is referred to as walleye pond harvest which continues through the end of October.
The amount of fingerlings stocked into a lake is based on the littoral acreage of each individual lake. Littoral acreage is the number of acres of the lake that is 15 feet in depth or less. The standard stocking rate is a pound of fingerlings per littoral acre. For instance, a lake with 450 littoral acres will be stocked with 450 pounds of walleye fingerlings. The rate for each specific lake is identified in a lake management plan. Rates can vary depending on whether a lake is identified as a core walleye fingerling stocking lake or as a primary or secondary management species. Stocking frequency is also identified in the lake management plan. The standard fingerling stocking rotation is every other year; however, a few lakes are stocked every third year or two out of three years.
Walleye fingerling stocking allows area DNR fisheries managers to manage for walleye angling opportunities in lakes where walleye populations would otherwise be nonexistent or exist at very low densities due to a lack of walleye natural reproduction. Walleye natural reproduction is typically limited in these lakes due to a lack of suitable spawning habitat. Walleye fingerling stocking is not a panacea however. The vast majority of walleyes caught each year in Minnesota are the result of walleye natural reproduction. Approximately 95% of the walleyes caught and harvested each year are from lakes that are not stocked. Most of those fish are produced in Minnesota’s large natural walleye lakes. Examples of these lakes are Red Lake, Lake of the Woods, Leech Lake, and Cass Lake. In Otter Tail County, the most renowned walleye fishing lakes are ones that are not stocked. Walleye populations in these lakes sustain themselves at much higher levels than ever could be achieved by stocking. These lakes include Big and Little Pine, Rush, Otter Tail, and South Ten Mile.
Walleye fingerling stocking is a tool DNR fisheries managers can use to maintain fishable walleye populations in some lakes; however, Mother Nature (natural reproduction) is going to remain the most important element in keeping Minnesota one of the premier walleye angling states in the country.