. Bulletin. Natural history; Natural history. 454 Illinois Natural History Survey Bulletin Vol. 31, Art. 10 adults. Squaniaiion was complete at this stage. At a slightly larger size ju- veniles began to take on the form, pattern, and coloration illustrated in Fig. 3. L. symmetrkrLs from Wolf Lake grew at a decreasing rate (Fig. 7) and reached I • I 21 Y= + LOG X. 22 21 54 36 58 Fig. 7—Size distribution by age of Lepomis symmetricus collected in Wolf Lake between 21 June 1973 and 30 May 1974. Data from 27 May 1975 and 12 December 1974 are included. Black dots represent sample means for
. Bulletin. Natural history; Natural history. 454 Illinois Natural History Survey Bulletin Vol. 31, Art. 10 adults. Squaniaiion was complete at this stage. At a slightly larger size ju- veniles began to take on the form, pattern, and coloration illustrated in Fig. 3. L. symmetrkrLs from Wolf Lake grew at a decreasing rate (Fig. 7) and reached I • I 21 Y= + LOG X. 22 21 54 36 58 Fig. 7—Size distribution by age of Lepomis symmetricus collected in Wolf Lake between 21 June 1973 and 30 May 1974. Data from 27 May 1975 and 12 December 1974 are included. Black dots represent sample means for both sexes combined. In total, 233 speci- mens are represented. one-half of the first year's mean growth in approximately 10 weeks. The rela- tionship between standard length (Y) and age in months (X) expressed for the sexes combined is Y = + log X, with r = Males grew at a slightly more rapid rate than females but were not significantly larger than females. At 13-18 months males aver- aged mm and females averaged mm (t = , df = 11). At 19-24 months males averaged mm and females averaged mm (t = , df = 14). The largest specimen exam- ined from Wolf Lake was a female collected 25 July 1973. In other parts of its range L. symmelricus is known to attain a greater length, and specimens as long as mm have ijeen collected (TU 148—St. Tam- many Parish, Louisiana). Based on the collections examined, such large size is imusual, with most adidts rang- ing between 55 and 60 mm. DEMOGRAPHY Density The nature of the habitat of L. sym- metricus made population density mea- surements difficult, since submerged logs, brush, and vegetation prevented thorough sampling of a given area. However, on two occasions approx- imately 5 months apart quantitative samples of L. symmelricus were taken in Wolf Lake by repeatedly seining a measured shallow margin of the lake until no more individuals could be collected. The number collected was
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