The Effect of the Dye Aquashade ® on Water Quality, Phytoplankton, Zooplankton, and Sunshine Bass, Morone chrysops × M. saxatilis , Fingerling Production in Fertilized Culture Ponds

Rooted macrophytes make harvesting fingerling fish difficult because they can smother fish or tangle in the seines during harvest. Aquashade ® , a dye, is used to reduce macrophyte growth. Fingerling culturists are reluctant to use it because it may reduce phytoplankton concentrations and zooplankton food supplies of larval fish. Aquashade was applied at 4 mg/L (twice the recommended rate) to three ponds when filled and to three ponds when fry were started on prepared feed. Three ponds served as a control. All ponds were stocked with sunshine bass larvae at 15,000/0.04 ha. Water quality and plankton were monitored daily until harvest. Few differences were found among treatment ponds for water quality, chlorophyll a , primary productivity, phytoplankton and zooplankton concentrations, or weight of rooted macrophytes. Unionized ammonia and pH increased to potentially harmful levels in ponds that did not receive the dye. No differences were found in the number, total weight or percent survival of fingerlings harvested. No differences in average individual total length, total weight, or coefficient of condition were found either. At the concentration of dye used, the dye was not effective for rooted macrophyte control but may offer fish some protection from high pH or unionized ammonia concentrations.