The Natural Lakes Research team provides high quality and relevant research information to fisheries management and hatchery programs to enhance fisheries resources in Iowas natural lakes.
Contribution and Survival of Stocked Muskellunge, and Population Dunamics of Adult Muskellunge in Spirit, East Okoboji, West Okoboji, and Clear Lake
Muskellunge are produced in Iowa hatcheries and stocked in natural lakes and reservoirs to provide anglers with “trophy” angling opportunities. Efficient stocking strategies are necessary to reduce production costs and to provide desired muskellunge population densities. Our objective was to evaluate the stocking contribution and survival of pellet-reared and minnow– reared muskellunge stocked in either the fall (fingerlings) or spring (yearlings). Minnow-reared muskellunge fingerlings survived much better than pellet-reared fish, most likely due to there larger size (10-13 inches), better camouflage barring, and better health. Moreover, this research also discovered that minnow-fed yearlings stocked in the spring survived much better than these same fish stocked in the fall.
Stocking Survival and Population Dynamics of Adult Walleyes in Iowas Large Natural Lakes
Natural production walleye in Iowas natural lakes is extremely limited, therefore, annual stockings of fry and fingerlings are necessary to sustain these fisheries. Current research monitor broodstock densities, assess various life history characteristics of the broodstock populations, and evaluate stocking success. Populations are being monitored using creel surveys, mark and recapture tagging, and extensive age and growth analysis. This information helps us understand the impacts of changes in harvest regulations and stocking strategies. Ultimately, findings will guide decisions and strategies for managing walleye populations in Iowas natural lakes.
Shallow Lake Renovation Based on Alternative Stable Trophic States
Shallow natural lakes in Iowa are notorious for poor water quality. Shallow lakes are known as “tweeners” since they are too shallow to be consistently good lakes, and too deep to be consistently good marshes. When these lakes are in the turbid water state they are characterized by very turbid water, little to no aquatic vegetation, limited emergent vegetation, a sparse fishery dominated by carp and bullheads, and limited waterfowl production. However, many of these same lakes can also be in a clear water state which is typified by clear water, abundant aquatic vegetation, shallow bays covered with emergent vegetation, a desirable fishery dominated by sport fish species, and enhanced waterfowl production. The goal of this project is to develop tools that managers can use to shift and maintain shallow lakes in a clear water state.