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Redear sunfish display great variation in spawning season. Within most of their range, redear sunfish usually begin to spawn in May to June, and may continue to spawn until September (Schoffman 1939; Dineen 1968; Pflieger 1975). Redear may spawn sparingly during the summer and heavily in the early fall (Swingle 1949). In Florida redear sunfish begin to spawn in late February or early March and continue to spawn intermittently until October 1 (Clugston 1966). In the northern reaches of their distribution (Michigan, Illinois, and Indiana), nesting begins in May to July and generally does not extend into late summer (Krumholz 1950; Cole 1951; Childers 1967).

The eggs are laid in saucer-shaped nests, fanned free of debris (Gresham 1965; Wilbur 1969). Redear tend to be community spawners, often with nests only a few inches from each other (McCl ane 1955; Clugston 1966; Emi g 1966; Pflieger 1975). Nests have been found at water depths from approximately 5 to 10 cm (Swingle and Smith 1947; Gresham 1965; Emig 1966) to 4 to 6 m (Wilbur 1969). Gresham (1965) and Clugston (1966) reported that nests were usually at water depths of 45 to 90 cm. McClane (1955) reported that spawning most often occurred at depths of 91 to 122 cm in the St. Johns River; Swingle and Smith (1947) reported that nests in ponds were most often at water depths of at least 183 cm.

Redear sunfish grew faster and reproduced more abundantly in average turbidities of s 25 ppm (Buck 1956b). Although redear sunfish were reported to reproduce and young redear were recovered in a pond with a high turbidity (174 ppm) in one study, the critical level for successful reproduction and growth over time is probably between 75 and 100 ppm (Buck 1956b). Although redear prefer clear waters, redear sunfish seem to be more tolerant of turbidity than bass or bluegills (Buck 1956b; Smith 1979).

Adult. The best growth for redear was reported to occur at temperatures \of 23.9° C by Rounsefell and Everhart (1953), but Leidy and Jenkins (1977) reported the optimum or preferred temperature for growth of bluegill s , sma11mouth bass, and largemouth bass to be 27° C. At acclimation temperatures of 16° C, 21° C, and 26° C the redear sunfish selected temperatures at 22° C, 23° C, and 28° C, respectively (Hill et al. 1975). From this information the author assumes optimal temperatures for redear growth range from 24 to 27° C. Cole (1951) reported that bacterial fin rot and fungus attacked redear sunfish almost continuously in aquaria once temperatures fall below 14.4° C. Below 6.6° C, redear were inactive and did not feed. It is assumed that redear growth ceases when temperatures fall below 10° C, as is true for bluegills (Anderson 1958). A lower lethal temperature of 6.5° C was determined in reservoirs by Leidy and Jenkins (1977). Redear sunfish are susceptible to rapid temperature changes (Swingle 1949; Rounsefell and Everhart 1953).