. Bulletin. Natural history; Natural history. 504 Illinois Natural History Survey Bulletin Vol. 32. Art. 4 loo- se- 60- 1)0- 20- FISH AND CRAYFISH â¡ = INTAKE â = DISCHARGE Jni JIL IJ. 100- 80- LU g 60- LU § 20- 1 I u 100- 50- 40- 20- ZOOPLANKTON iL 6 15 20 N-INTAKE 5 8 15 32 31 34 N-DISCHARGE âI Fâ 50 60 70 1 1 1 1 1 1 1 r-//-| 1 rV/n 1 1 r 80 90 100 110 120 130 WO 150 200 250 300 400 500 500 700 800 FISH TOTAL LENGTH (mm) Fig. 1.âAverage weight percentages of major foods found in largemoutfi bass of different lengtfis from the intake and discharge arms of Lake Sangchris during 1974 and 1975
. Bulletin. Natural history; Natural history. 504 Illinois Natural History Survey Bulletin Vol. 32. Art. 4 loo- se- 60- 1)0- 20- FISH AND CRAYFISH â¡ = INTAKE â = DISCHARGE Jni JIL IJ. 100- 80- LU g 60- LU § 20- 1 I u 100- 50- 40- 20- ZOOPLANKTON iL 6 15 20 N-INTAKE 5 8 15 32 31 34 N-DISCHARGE âI Fâ 50 60 70 1 1 1 1 1 1 1 r-//-| 1 rV/n 1 1 r 80 90 100 110 120 130 WO 150 200 250 300 400 500 500 700 800 FISH TOTAL LENGTH (mm) Fig. 1.âAverage weight percentages of major foods found in largemoutfi bass of different lengtfis from the intake and discharge arms of Lake Sangchris during 1974 and 1975. found here to be mainly insectivorous. Young-of-the-year bass were reported not to have preyed upon fish consistently un- til they reached a total length of 90-100 mm. The data presented here indicated that for largemouth bass in Lake Sangchris the complete shift from insec- tivore to piscivore may occur at around 140 mm. According to size, bass from both arms of Lake Sangchris showed about the same food habits. Those in the intake arm ate more insects and less fish than those in the discharge arm until the com- plete shift in food habits occurred. From fish of that size to the largest bass examin- ed, reliance upon fish as forage was equally great in both the intake and discharge arms of the lake. These trends were evident during both 1974 and 1975. For the best analysis of feeding seasonality, it is essential that com- parisons of similar-sized fish be made at frequent intervals throughout the year. As in most analyses, the effort required for such comparisons proved too great, and conclusions had to be based upon smaller samples. In general, though, con- sumption of fish by bass in both arms of the lake was high during each Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Illinois. N
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Keywords: ., booka, bookcentury1900, bookdecade1910, booksubjectnaturalhistory
