IOWA (Cont.) 



five days of netting the following spring produced an estinnate of 1, 503, 959 bull- 

 heads or about 800 pounds per acre. Removal of one -half of this population 

 failed to produce a satisfactory growth in the following two seasons. Marked 

 fish have been stocked in Center Lake prior to ice breakup this spring, to form 

 the basis for another population estimate. 



Center Lake, Dickinson County; began October 1950, to close November 1953; $200; 

 E. T. Rose and Tom Moen, Proj. Ldrs. ; Qxiarterly Biology Report, Vol. 111(2), 

 1951, available. 



Address correspondence to: E. B. Speaker, Supt. of Biology, Iowa State Conser- 

 vation Commission, East 7th and Court Sts. , Des Moines, Iowa. 



A Study of Hatchery Techniques. 



The project was set up to study general hatchery procedures as they are concerned 

 with the hatching and stocking of yellow pike-perch and northern pike. Basic 

 data is collected on production (total number of eggs), number of eggs per quart 

 (size), size at various stages of development, fertility, temperatures, and 

 numbers and sex of fish handled. Some experimental work is being carried on 

 in methods of handling both eggs and fish. 



Spirit Lake and Clear Lake hatcheries; began in April 1946, continuing; $500; Tom 

 Moen, Proj. Ldr.; some reports available. 



Address correspondence to: E. B. Speaker, Supt. of Biology, Iowa State Conser- 

 vation Commission, East 7th and Court Sts. , Des MoineSy Iowa. 



Blue-green Algae Control. 



Several fishing and general recreation lakes of Iowa develop large blooms of blue- 

 green algae which are unsightly and occasionally toxic to waterfowl and domestic 

 animals. Aid of a technical nature is provided to communities or organizations 

 in administering copper sulfate to control these growths. A study of toxic algae 

 is receiving special consideration due to waterfowl losses in the fall of 1952. 



State Lakes; began June 1952, indefinite; Earl T. Rose, Proj. Ldr. ; Mid-West 

 Wildlive Conference Report, 1952 and Quarterly Report Dec. 1952, available. 



Address correspondence to: E. B. Speaker, Supt. of Biology, Iowa State Conser- 

 vation Commission, East 7th and Court Sts. , Des Moines, Iowa. 



The Value of Stocking Walleyes in Iowa Streams. 



The object of this investigation is to study the possibility of supplementing our stream 

 fisheries by the introduction of hatchery-reared walleyes. Stocking in on an alternate 

 year basis. Collections of scales are made to determine whether or not the major- 

 ity of fish caught come from the years in which walleye are planted. 



In streams in the northeast quarter of the State; began May 1950, continuing; R. E. 



Cleary and Harry M. Harrison, Proj. Ldrs. 

 Address correspondence to: E. B. Speaker, Supt. of Biology, Iowa Conservation 



Commission, East 7th and Court Sts. , Des Moines, Iowa. 



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