536 U. S. BUREAU OF FISHERIES 
KEOKUK DAM AND THE FISHERIES OF THE UPPER MISSISSIPPI 
RIVER 
Immediately after the dam was constructed across the Mississippi 
River between Keokuk, Iowa, and Hamilton, Ill., there was begun 
a study of the effect of this and other changes in the Mississippi 
River upon the fisheries above the dam. ‘The investigation was 
under the direction of Dr. R. E. Coker, then director of the fish- 
eries biological station at Fairport, Iowa. An investigation of this 
kind necessarily involved observations over a long period of time. 
The process of adjustment of living animals to the changing con- 
ditions of environment in a stream is so gradual that safe conclusions 
can be drawn only after years of study. It would have been desirable 
if the observations could have been continued year after year without 
interruption, but this was not possible. The problem has not been 
out of mind, however, and studies have been made from time to 
time and tentative reports have been prepared. ‘The time now seems 
ripe to put into form for publication the considerable data secured 
in the investigation. Accordingly, during the past year Doctor 
Coker undertook to complete the report and to make additional 
observations in the field. Accompanied by H. L. Canfield, he visite 
the Mississippi River at various points between Lake City, Minn., 
and Canton, Mo. The additional data gathered this year are now 
being incorporated in the report, which is nearing completion. 
WESTERN TROUTS AND OTHER COLLECTIONS 
In addition to investigating the New England smelt fisheries, 
Dr. W. C. Kendall also was occupied intermittently in studying and 
classifying trout material contained in numerous hitherto unstudied 
or little studied collections of trout from the Western States and 
Alaska, which represent years of accumulation. Inasmuch as these 
specimens were collected before the regions from which they came 
were affected by extensive fish-cultural distribution of nonindigenous 
species, this study is expected to throw greatly needed light upon the 
relationship of western species, and particularly upon the much- 
rooted problem of the so-called rainbow and steelhead trouts. 
The wide fish-cultural distribution of these species and the varied 
experience with them in the east and abroad have given rise to a 
number of questions concerning them, and from time to time inquiries 
have been received for information and opinion. An inquiry par- 
ticularly difficult to answer was from Doctor Ehrenbaum, of Ham- 
burg, Germany, who wished to ascertain the specific identity of 
rainbow trout imported into Germany. Doubtless the rainbow- 
trout eggs sent to Germany were from the same two or three different 
species that seem to compose the mixture that (at least in the past) 
has been distributed from the hatcheries under the one name, “ rain- 
bow trout.” 
During the summer, through the Bureau of Fisheries, five speci- 
mens of rainbow trout, which were the result of introduction, were 
received from H. L. Kelly, executive officer of the fish and game 
commission of the Territory of Hawaii, with the request that they 
be identified. 

