In this same period, the number of commercial mussel fishermen working 

 between Meredosia and Naples fell from 200 to 25-35 (Danglade, 1914- 21) 

 The total value of shells and pearls taken from the river dropped from 

 $139,000 ($836,085 in 1977 dollars) in 1908 to $128,692 ($696,738 in 

 1977 dollars) in 1913 (Table 5 ). 



Although the data are incomplete for the years following 1913 

 the values of the 1922 mussel catch and the 1931 catch were greatly 

 reduced from previous years (Table 5 ). After World War II plastic 

 generally replaced shell material in the manufacture of buttons. The 

 mussel catch data for 1956 and 1958 follow the trend of previous 

 years, showing greatly reduced harvests and values (Table 5). 



From 1961 to 1966 the number of mussel-fishing licenses sold in 

 Illinois rose from 69 to 1,279 (Lopinot, 1968: 6). A rise in mussel production 

 paralleled the rise in license sales and the harvest from the Illinois 

 River topped 1,000 tons in 1965 and 1966 (Table 5). The Wabash and 

 Mississippi Rivers were the other main mussel-producing waters of the 

 state during this period, with shells from the Wabash being of the best 

 grade and commanding significantly higher prices (Lopinot, 1968- 10- 

 Starrett, 1971: 268). During the revival of this fishery most of the 

 shell beds fished commercially were located in Alton Pool (Starrett, 1971- 390) 

 These beds possessed substantial standing crops of mussels (Starrett, 1971- 390) 



By 1970 shell production had dropped to only 54,000 pounds from 

 the entire river (Table 5 ). While a reduction in the kinds of mussels 

 in the pool has taken place, this reduction did not affect the commer- 

 cial catch significantly as the remaining species are the types favored 

 by the pearl-culture industry. Although mussel fishing has not been 

 economically worthwhile since 1972, the market has begun to improve 

 recently, as mentioned previously. 



Effects of the Navi gation S ys tem on the Ifaggej f^ Specific ef- 

 fects of the navigation system on mussels are difficult to pinpoint as 

 the river has been subjected to varying degrees of other potentially 

 detrimental influences. According to Starrett, conditions for mussels 

 in the Pool have generally worsened since 1930: 



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