. The changing Illinois environment : critical trends : technical report of the Critical Trends Assessment Project. Man; Pollution; Environmental protection; Ecology; Environmental impact analysis. i 60 OS 50 OS 40 OS 30 OX 20 OS 10 OS 0 OS -10 OS -20 OS -30 OS -40 OS -50 OS -60 OS I Mississippi River â â >â â â Illinois River Other large nvers â O- - Small Streams. Figure 15. Number of days spent sport fishing in Illinois. More then million anglers sport fished in Illinois during 1989, with only of the anglers being from outside the state. Anglers averaged fishing trips in Il
. The changing Illinois environment : critical trends : technical report of the Critical Trends Assessment Project. Man; Pollution; Environmental protection; Ecology; Environmental impact analysis. i 60 OS 50 OS 40 OS 30 OX 20 OS 10 OS 0 OS -10 OS -20 OS -30 OS -40 OS -50 OS -60 OS I Mississippi River â â >â â â Illinois River Other large nvers â O- - Small Streams. Figure 15. Number of days spent sport fishing in Illinois. More then million anglers sport fished in Illinois during 1989, with only of the anglers being from outside the state. Anglers averaged fishing trips in Illinois during the year, with resident anglers averaging trips and nonresident anglers averaging trips. In 1990 anglers spent over 41 million days fishing in Illinois' lakes, ponds, and streams. At the current rate of increase, by the year 2010 the number of angling days is likely to increase by over 40% to approximately 57 million angling days per year (one angling day is one fisherman fishing all or any part of a day). The above projection was created from a regression analysis (V= .802) of angling day estimates from 1965 to 1990. Source: Office of Resource Management, Division of Fisheries, Illinois Department of Conservation, Springfield. (Figure 17). Catfish, black bass, walleye and sauger, and crappie have remained the top four groups of sport fish sought after since 1977 (Figure 17). Of the four groups however, black bass have continually risen in popularity while preference for the others has remained fairly stable. Fish Kills Attributable to Pollution Streams are occasionally subject to disturbances so severe that they result in unusually high mortality of animals or plants in an area. Normally such distur- bances result from natural causes (, severe floods or droughts; see Hynes 1970), but they can also be induced by human activities. Fortunately, a common result (, high mortality of fish) of such human perturbations to streams usually is quite
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