Forest Preserve District of Cook County, Illinois
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Fish, Weather and People
Nature Bulletin No. 241-A   October 22, 1966
Forest Preserve District of Cook County
Seymour Simon, President
Roland F. Eisenbeis, Supt. of Conservation


Fishing can be one of the cheapest and most satisfying forms of recreation for people of all ages and both sexes. The proudest moment for many a boy is when he comes home with a big catfish or a string of bluegills caught with a can of worms for bait, and a cane pole or a willow cut from a thicket. Fishing can also be an expensive sport when the fisherman, laden with gadgets and high-priced tackle, journeys long distances to northern waters.

The time of year, the sign of the moon, the barometric pressure, the direction and velocity of wind, rainfall, the amount of fishing and other conditions are some of the reasons given by credulous fisherman to bolster up their alibis. None of them can be proved. We do know that, in general, in the streams, ponds and inland lakes of Illinois, the principal fish caught in early spring are bullheads and, after them, the crappies. In summer the catches are mostly bluegills and largemouth black bass. In autumn, often, we again get good strings of crappies. But beyond that, as far as we know, in only one body of water has there been kept sufficient records over a long term of years, and a scientific study of such records, to throw any light upon the theories about why and when fish bite or don't bite.

Rinaker Lake, a 14-acre impoundment near Carlinville, Illinois -- about midway between Springfield and St. Louis -- has been used for almost 50 years by a club of local people to furnish some of the best year- round fishing in the state. From 1932 to 1943, a careful day-to-day record was kept of each angler's catch, to serve as a guide for the management of the lake. During this 12-year period, a total of over 15,000 pounds of hook-and-line fish was taken. This amounted to 3-1/4 pounds per fisherman per trip -- over twice as good as the average success in other waters of Illinois. The catch was made up almost exclusively of four kinds -- largemouth black bass, white crappies, bluegills and black bullheads. Although each of these kinds, in certain years, made up a much more important part of the total catch than in other years, the total average catch per fisherman' s trip was about the same from year to year.

These records and the records of the local weather station were used to test some of the beliefs that weather has a lot to do with the best time to fish. One of the oldest ideas is that fish bite better during and following rains. There was a moderate increase in the average catch on the 244 days when over a half inch of rain fell but there was little effect during the days that followed except that bass bit almost twice as well when the water cleared up, two or three weeks later. Whether it was sunshiny or cloudy made little difference. Neither did wind direction, possibly because the lake was so small that there could be little wave action.

Some fishermen claim that fish bite better on days with a high barometric pressure, and others that a rising barometer is best. This was tested in detail, using US Weather Bureau records, but there was no evidence of any effect. Incidentally, fish rising or sinking through a few inches of water undergo greater pressure changes than the most extreme changes shown by the barometer during the course of a year. Both bluegills and crappies seemed to bite a little better in the light of the moon than in the dark of the moon but the average difference was only a few percent. Further, confirmed anglers fishing one or more times each week had no better luck than persons who fished only a few times a year. During the entire twelve years, men averaged 3.25 pounds per day, while the women averaged 3.22 pounds.

Of course, the men say they hooked a lot of big ones that got away.

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