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BULLETIN OF THE BUREAU OF FISHERIES 
ductive had the submerged woodlands been more generally cleared before the lake 
was filled. One might have the impression that land such as is represented in Figure 
16, had it been cleared of vegetation and left to form spaces of open water, would 
have produced more useful plankton (drifting microorganisms, both plant and 
animal), would have supported more rooted aquatic plants to serve as food producers 
and oxygenators, would have contributed less to the deoxygenation of the lake, and 
would have afforded better breeding places for fish. One might have this impression, 
but the precise observational and experimental data to substantiate or to contradict 
such an inference are now lacking. It might be suggested that refuge is a primary 
need of young fish, and that this is afforded by the submerged brush and fallen 
trees; but refuge can also be offered by rooted aquatics, which at the same time 
serve other useful purposes to aquatic animal life. Since the question is continually 
arising as to the propriety of fully clearing lands that are to be submerged by the 
formation of lakes and fish ponds, there is obviously a very practical sort of problem 
in this that awaits critical study. 
The preceding paragraphs were written prior to the author’s last visit to the lake 
in 1926, when it was found that the aspect of the lake had changed greatly in respect 
to the submerged islands and shores. Where forests of dead trees had stood on 
submerged lands (fig. 16) there were now chiefly stumps and a dense growth of 
Sagitaria and other aquatic plants (fig. 17). Doubtless some of the trees had rotted 
at the base and fallen, but it was said that many of them had been cut away during 
the winter, when residents of the shores could work on the ice and haul the wood 
away for use as fuel. Where the lake in 1917 had presented the aspect of winding 
passages amongst heavily wooded areas, there was in 1926 uninterrupted view in 
all directions. Shallows still prevailed over submerged islands and shore lands, but 
the water in such places was subject to more severe wave action. (Coker, 1930.) 
The Green Bay region and adjacent territory, as has been mentioned previously, 
had been removed from the lake entirely and converted into agricultural lands, 
thus eliminating some of the best breeding and nursery grounds for fish. 
ABUNDANCE OF FISH 
During 1914, 1915, and 1916 several visits were made by Stringham to the 
markets at Burlington, Iowa; during 1915 and 1916 to those at Fort Madison, Iowa, 
and to fisheries at Nauvoo, 111.; and during 1916 to newly established fisheries at 
Montrose, Iowa. There was a tendency at first to complain that fish were less 
abundant than theretofore; in 1915 this was substantially confined to two species — - 
the Missouri sucker, a southern species never common here, and the shovelnose 
sturgeon. By 1916 the complaints had about ceased. It seemed clear, however, 
that the sturgeon fishery was ended for the southern end of the lake, and that it had 
probably diminished above. Against this, there had been gains in carp, catfishes, 
and drum, and possibly in buffalo fishes and black bass. As to game fishes, little 
or no complaint was heard at any time. There was observable a distinct develop- 
ment of the commercial fishery with the use of more and larger apparatus. The 
statistics of the commercial fishery for 1922, to be discussed later, will show that the 
gains had been maintained for black bass, catfish, and drum, but not for carp and 
buffalo fishes. The sturgeon fishery apparently had disappeared in that year. 
In 1917 the author interviewed fishermen and dealers at Fort Madison, Dallas 
City, and Burlington and on Green Bay. The general purport of the information 
