Ada Hayden Heritage Park, Ames, Iowa, a mesotrophic quarry-pit fishery, was opened for new public exploitation on July 1, 2004 after many decades of private ownership and limited exploitation. A monthly, electro-fishing, population survey was conducted to both characterize the fishery and document any significant angler impacts from June 2003 to October 2004; an expandable creel survey was conducted from July 2004 to October 2004 to estimate angler use and analyze harvest change. The fishery is characterized by little to no structural habitat, high water quality, high diversity of 32 fish taxa including gizzard shad, low sport fish biomass, and an unbalanced bluegill population. Angler use peaked in July 2004 with 220 angler hrs/ha and fell rapidly to low levels. Creeled crappie, channel catfish, and yellow perch saw significant declines in average weight over time. Creel catch per unit effort (CPUE) did not significantly change as angling progressed for any species. Approximately 80% of the total fish biomass harvested since July 2004 was crappie species. Bluegill, channel catfish, yellow perch, freshwater drum, and green sunfish comprised the remaining 20%. Angler exploitation rate of bluegill [greater than or equal to] 100 mm during the creel period was 13%. No significant changes in CPUE, proportional stock densities, and relative weights were detected after this fishery was opened to public fishing. However, largemouth bass stomach analyses indicated increased gizzard shad use after exploitation began. Due to the limited scope of the post-exploitation study period, future changes due to exploitation may be possible.