Blooms of toxic phytoplankton, including cyanobacteria, plague aquaculture production ponds given that some cyanobacteria can produce (1) potent toxins that can kill fish and (2) off-flavor compounds that make fish taste earthy. Controlling algal blooms is complicated given that nutrient management is difficult in active aquaculture ponds. Chemical methods, such as copper sulfate, are often effective at killing phytoplankton but tend to have to be used repeatedly because their effects are short-lived or don’t select for higher quality phytoplankton species. Hydrogen peroxide is an approved FDA treatment but not often used at the whole aquaculture pond scale. Using lab and field experiments, we found that hydrogen peroxide doses ~7 mg/L reduce cyanobacteria and algal toxins while promoting high quality green algae. Biological methods, including foodweb manipulations, that promote large-bodied zooplankton, such as Daphnia, show promise as effective and sustainable approaches for managing algal blooms. With a new USDA-NIFA grant, Alan Wilson and Luke Roy along with our students will conduct whole pond experiments aimed at promoting cyanobacteria-resistant Daphnia that naturally eliminate cyanobacteria in catfish aquaculture ponds.
Zhen Yang — email@example.com