Effects of supplemental feed on bluegill growth and reproduction

Several pond enhancements are commonly used to increase fish production or enhance angling opportunities, but their effects are rarely evaluated.  We investigated whether providing supplemental feed to bluegill leads to higher bluegill reproductive rates as measured by growing season larval fish density and fall age-0 density. In April 2009, adult bluegill were stocked in nine 0.1-ha ponds (125/pond); ponds were provided with no pelleted food (control), a low ration (1.52 kg/ha/d), or a high ration (2.68 kg/ha/d) from May to September.  Ten largemouth bass (mean TL = 140 mm) were stocked into each pond in late July.  Supplemental feeding increased growth of initially-stocked bluegill compared to the control, but growth did not differ between low and high ration treatments.  In contrast, larval bluegill density during the growing season and the final number of age-0 bluegill at experiment’s end did not increase with feeding.  Whole-body caloric density of age-0 bluegill was higher in both feeding treatments versus the control. These results indicate that supplemental feeding improves bluegill growth, but not reproductive output.  However, the quality of potential forage for largemouth bass was higher with supplemental feeding, potentially enhancing largemouth bass growth and condition.