. The changing Illinois environment : critical trends : technical report of the Critical Trends Assessment Project. Man; Pollution; Environmental protection; Ecology; Environmental impact analysis. Figure 17. Hierarchy of the most sought sport fish species in Illinois, 1977-1989. This figure demon- strates that catfish species continually receive the highest fishing pressure, approximately 40% of the total number of angling days. Fishing pressure on black bass species has steadily increased since 1977. Wallye/sauger and crappie were the third or fourth most preferred species during this period
. The changing Illinois environment : critical trends : technical report of the Critical Trends Assessment Project. Man; Pollution; Environmental protection; Ecology; Environmental impact analysis. Figure 17. Hierarchy of the most sought sport fish species in Illinois, 1977-1989. This figure demon- strates that catfish species continually receive the highest fishing pressure, approximately 40% of the total number of angling days. Fishing pressure on black bass species has steadily increased since 1977. Wallye/sauger and crappie were the third or fourth most preferred species during this period. Although the popularity of these species does seem to be constant, it is important to realize that each year the absolute pressure received by any one of these species is The IDOC immediately investigates all reported fish kills and files a report including, when possible, an assessment of the probable cause of the high fish mortality. These records, then, serve as a rough index of one aspect of the relationship between Illinois and its flowing waters. Between 1962 and 1991, an annual average of fish kills that could be attributed to non-natural causes were reported from flowing waters in Illinois. These kills resulted on average in the loss of 532,000 fish annually. The data suggest that the annual number of fish kills has not declined over time; rather, there has been a trend toward an increased number of pollution-caused fish kills per year (Figure 18). The mean number of kills in the first 15 years of the 30-year period ( ± [SE]) is less than the mean number in the past 15 years ( + [SE]). Since 1966, the number of fish kills reported per year has increased significantly (linear regression; P < .05) despite large year-to-year fluctuations. There has been no obvious trend in the estimated number of fish killed per year (Figure 18). It is often difficult to ascertain the cause of a given pollution-caused fish kill, but two trends in the dat
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Keywords: ., bookcentury1900, booksubjecte, booksubjectecology, booksubjectman
