Crayfish, frogs, snails, and insect larvae are also utilized at times. The walleye is relatively easy to propagate and rear in hatcheries. Nearly l25 million walleye fry are produced each year in Iowa for stocking larger lakes and reservoirs throughout the state. A smaller number are also raised to fingerling size in shallow nursery lakes and in concrete raceways prior to planting. Walleye typically reach 5.5 inches in length the first year and about 9.3, 12.4, 15.2, 17.4, 19.2, 20.6, 21.7, 22.1 and 23.2 inches in the succeeding 8 years.
Females grow more rapidly and attain a larger maximum size than males.
The current Iowa record walleye was caught in Spirit Lake during l968. Several larger individuals have been reported in netting operations for brood fish.