income for Illinois fishermen since 1972, indications along the river 

 are that the market may improve soon (Bellrose et al. , 1977: C-117). 



Pre- and Post-Dam Mussel Harvests . A comparison of reported 

 mussel catches in pre- and post-dam construction years is difficult 

 considering the paucity of available data. Also, harvest information 

 by species is not available. Possible effects of the navigation 

 system on the mussel catch will be discussed later. 



The earliest reliable commercial mussel harvest information 

 for the Illinois River is contained in a statement made by 

 Danglade: 



The Illinois /River/ reached its maximum shell production 

 during the season of 1909, when thousands of tons of good 

 button shells were gathered and put in piles along the shore 

 to await shipment. (1914: 8) 



Danglade also found that in 1912 the mussel fishermen in the river from 

 Kampsville (river mile 32.0) to Grafton (river mile 1.0) averaged a 

 daily yield of 500-700 pounds of shells per man (1914: 23). 



Other pre-construction years for which data are available are 

 1922 and 1931 (Table 5) . While these figures compare favorably 

 with the "thousands of tons" Danglade mentioned, the 1931 harvest 

 represents a 62.5 percent reduction from the 1922 harvest. 



Post-construction mussel catch information to 1963 shows harvests 

 which are greatly reduced from 1922 and 1931 figures. However, with 

 the advent of the pearl-culture industry, the mussel catch peaked in 

 1965 and 1966 to over 1,000 tons (Table 5). These figures are 

 similar to pre-construction catches. This increased catch was short- 

 lived and catch figures since 1968 are significantly reduced, with 

 no reported catch since 1970. The catch was reduced after 1968 

 because the market had been glutted and the Japanese had stockpiled 

 shell. The stockpiles have been reduced and the Japanese are buying 



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