Comparative Growth of Four Species of Fish in Three Different Types of Iowa Artificial Lakes

Growth of four species of fish are compared in three different types. of Iowa artificial lakes and reservoirs. The lakes were classified by similarity of physical, chemical, and biological characteristics. Scale samples and total length measurements were obtained from 14,705 fish at 71 impoundments. Largemouth bass, bluegill, black crappie, and white crappie growth was greatest in Group I lakes. Factors influencing differences in growth rate in the three types of impoundments are discussed. One of the ultimate goals of sport fishery management is to produce fish of harvestable size in the shortest period of time. Slow-growing fish are neither desirable to the angler, nor advall!tageous to the population structure. Before fishery management can be effective, expectations of maximum and/or minimum growth must be determined. These factors are readily established by comparative growth studies in varying environments. Since 1944, annual fishery inventories of reproduction and adult fish populations have served as the major tool for management of the sport fishery in Iowa recreational lakes. Limited studies of growth characteristics of major species of fish are an integral segment of these surveys. Approximately 15 scale samples are obtained from representative size groups of each species. Additional scales are also obtained from related projects such as, creel censuses and population eradications. These scales are aged by miroprojection and compared for rapidity of growth. Growth is determined by the total length of each individual specimen at a given age rather than mathematical calculation. This is a comparative study of the growth of largemouth bass ( M icropterus salmoides), bluegill ( Lepomis rnacrochirus), black crappie (Pomoxis nigromaculatus), and white crappie (Pomoxis annularis) in three different types of southern Iowa artificial lakes. Although this is not a complete list of sport fishes in the artificial lakes, these are the most popular and widespread. Scale samples were collected from 14,705 fish at 71 artificial lakes and reservoirs. The samples were separated into lake classification categories based on similarity of physical, chemical, and 1 Senior Biologist, Artificial Lakes and Reservoir Investigations, State Conservation Commission, Chariton, Iowa.