IOWA (Cont. ) 



Statewide; began in 1936, continuing. 



Address correspondence to: Glen Powers, Supt. of Engineering Construction, 

 State Conservation Comniission, East 7th and Court Sts. , Des Moines, Iowa. 



17. Natural Lake Survey. 



All of the natural lakes of Iowa managed for angling are surveyed by the Biology 

 section each year. This involves test seining with 500 feet of l/4-inch nnesh 

 (bar) seine at several stations on each lake. In addition, stationary gear {pound 

 and gill nets) are used to supplement the seine catch. The small-mesh seine 

 hauls are designed to determine primarily the magnitude of reproduction each 

 year, and the nets to determine population fluctuations and status of the adult 

 fishes. Fishes taken are sorted into young-of -the-year and older groups, 

 weighed, measured, and scale samples taken from representatives for age and 

 growth analyses. Data on vegetation, amount of bottom foods (dredge samples) 

 turbidity and lake chennistry are also obtained. This information is recorded on 

 forms and recommendations presented for possible improvem.ent of fishing. 



Northern half of Iowa; began July 1940, continuing; $5,000; Earl T. Rose, Proj. Ldr . 



reports available. 

 Address correspondence to: E. B. Speaker, Supt. of Biology, East 7th and Court 



Sts. , Des Moines, Iowa. 



18. Artificial Lakes Survey. 



A continuing inventory is maintained in the form of an annual netting survey and 

 limited limnological investigations of the artificial lakes. Although special em- 

 phasis is placed on the relative abundance of each species and extent of repro- 

 duction, other items such as age and growth (determined from subsamples), 

 abundance of bottom fauna, extent and species of vegetation, turbidity, and extent 

 of chemical and thermal stratification are also determined. These items are 

 recorded on standard forms for comparison from year to year. 



Statewide, but primarily in southern half of the State; began September 1947, con- 

 tinuing; $1,500; Tom Moen, Proj. Ldr. ; form reports available. 



Address correspondence to: E. B. Speaker, Supt. of Biology, East 7th and Court 

 Sts. , Des Moines, Iowa. 



19. Techniques of Fish Surveys in Streams. 



This project involves a study of the effectiveness of various types of gear used to 

 make stream and river surveys. At present, special emphasis is placed upon 

 determining the best gear suited to the rivers and streams of the type found in 

 Iowa and at what time of year and under what conditions they work best. The 

 types of equipment under observation include the conventional electrical gear, 

 traps and seines of various design used under a variety of conditions, and the 

 use of several instruments to drive fish into traps. In addition to this, studies 

 are underway to determine the possibility of making stream surveys xinder ice. 



Statewide; began July 1948, planned to November 1955; $2,000; R. E. Cleary and 



Harry M. Harrison, Proj. Ldr. 

 Address correspondence to: E. B. Speaker, Supt. of Biology, East 7th and 



Court Sts. , Des Moines, Iowa. 



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