568 
portion of the 1,000,000 to 1,500,000 pounds of fish marketed 
annually at Havana. 
The development in recent years of extensive systems of 
levees in the bottoms of the Illinois River for the purpose of 
protecting farm lands from untimely floods increases the impor- 
tance of, and necessity for, the reservoir backwaters. In con- 
nection with these systems it might be feasible from an engi- 
neering point of view, and perhaps even profitable from the 
commercial standpoint, to convert some of the adjacent low- 
lying marshes, swamps, bayous, and lakes into reservoirs in 
which invading and richly fertilized storm waters might be 
impounded and retained as river levels fall. The increased vol- 
ume of water thus provided should—in the light of our results 
—yield an abundant plankton, and support a large fish popula- 
tion. Under present conditions of abundance of most of our 
valuable food fishes in the Illinois, stocking such reservoirs 
is relatively a simple matter. If properly protected from es- 
cape at high water, such an area once-stocked with the now 
rapidly disappearing Polyodon, whose roe is much sought for 
the manufacture of caviar, might become a very profitable in- 
vestment. 
As a basis for further development of the fishing industry 
it seems desirable that public and private waters should be 
more accurately defined, and that fishing privileges for market 
purposes in the former should be matters of license or franchise 
to responsible parties, so that legislation concerning methods 
and seasons of fishing could be more easily controlled. With 
the ever increasing industrial development in the drainage ba- 
sin of the Ilhnois River, especially in Chicago and the minor 
cities along its banks, there is great danger that industrial 
wastes will so accumulate in the river waters that not only the 
plankton but also the fish and other animal inhabitants will be 
driven out or exterminated. Legal supervision over the dis- 
charge of such industrial wastes may soon become imperative 
for the Illinois River as it has for some European streams. 
With the legal status thus clearly defined, and with wise legis- 
