KEOKUK DAM 
91 
The continuity of such collections, made for other purposes summer after summer, 
have afforded many suggestions and served as a check upon premature generalizations. 
A study of the plankton, or minute fish food, of the lake and of the river above 
and below and an examination of the distribution of aquatic vegetation in the lake 
were made by A. A. Doolittle in 1914. War conditions prevented a repetition of 
this survey after a period of two or three years, as was considered necessary for the 
best use of such data for purposes of deductions. 
In the summer of 1921 Dr. Paul S. Galtsoff, of the United States Bureau of 
Fisheries, studied the composition, amount, and distribution of plankton in various 
parts of the Mississippi River from Lake Keokuk northward to Hastings, Minn., a 
few miles above Lake Pepin. His observations and conclusions have already been 
published by the bureau. (Galtsoff, 1924.) 
Statistical canvasses of the fisheries in Lake Pepin and in Keokuk Lake (some- 
times called Lake Cooper * * * 4 ) were made in 1915 by W. A. Roberts (for the year 1914), 
in 1918 by Arthur Orr (for the year 1917), in 1923 by various agents (for the year 
1922), and in 1928 (for 1927). 5 
Another source of valuable information was found in the regular records of fish 
stranded on the top of the lock gates during 1915, 1916, and 1917, kept by lock 
masters William Huele, Timothy Harrington, and Walter Raber by direction of 
Montgomery Meigs, civil engineer, United States Army. 
The officers and employees of the Mississippi River Power Co. have been uni- 
formly considerate and helpful, extending to the investigators free access to all parts 
of the plant as necessary for the purpose of investigation and furnishing all informa- 
tion requested as well as several of the photographs used in this report. The coopera- 
tion of United States Engineer Meigs in allowing the regular use of a trammel net 
on the top of the lock gate during several months of 1915 and the assistance of lockmen 
in the operation of the net deserve special mention. Many fish dealers and fisher- 
men (of Keokuk especially and of other places as well) have freely furnished information 
that has been indispensable to the effective conduct of the investigation, but their 
names are too numerous to mention. 
Grateful acknowledgment is also made for the opportunities and the encourage- 
ment extended by former Commissioner of Fisheries Hugh M. Smith and Deputy 
Commissioner H. F. Moore and, more recently, by Commissioner of Fisheries Henry 
O’Malley and Elmer Higgins, in charge of scientific inquiry. 
KEOKUK DAM AS A POSSIBLE OBSTRUCTION TO FISH 
The dam has been described at some length in a previous report, 6 and it is 
unnecessary to repeat the details in this report. The features of the dam most 
essential for a correct understanding of its relation to fishes may be stated briefly in 
the following way : 
Its location is across the Mississippi River, 1,435 miles by river from New 
Orleans (about 1,545 miles from the Gulf of Mexico) and 490 miles by river below 
< The mine Lake Cooper was originally given to the body of impounded water above the dam and therefore was employed 
by the bureau in preceding reports. The change in the present report to the use of the name Lake Keokuk is occasioned by the 
action of the TJ. S. Board on Geographic Names, which has officially sanctioned the latter designation. To avoid the possi- 
bility of confusion, however, it seems advisable to state that our remarks refer in no case to the locally well-known Keokuk 
Lake of Muscatine County, Iowa. 
4 The results of these canvasses, frequently quoted in this report, are found in full in the following publications: Reports, U. S. 
Commissioner of Fisheries, for 1916, pp. 58-60; 1918, pp. 75-80; Sette, 1925, pp. 210-212; and Sette and Fiedler, 1929. 
e Coker, Robert E.: Water-Power Development in Relation to Fishes and Mussels of the Mississippi. Appendix VIII, 
Report of the U. S. Commissioner of Fisheries for 1913. Bureau of Fisheries Document No. 805, pp. 11-18. 
