Prymnesium parvum blooms result in fish kills around the world and are devastating to fish hatcheries, where few management tools are available. Current control strategies include algaecides, nutrient management, and flocculation, which are moderately effective at best and can be toxic to nontarget organisms. A relatively new type of medium, registered by the U.S. Environmental Protection Agency for the control of fecal coliforms in storm water runoff, was evaluated as a possible P. parvum control tool. The medium, called Smart Sponge, was designed to absorb petroleum hydrocarbons; a variant, Smart Sponge Plus, is enhanced with antimicrobial properties. It is these antimicrobial properties that we investigated for possible use in algal bloom management. Our objective was to evaluate the efficacy of this type of medium on the eradication of P. parvum and its associated toxins, with a view toward advancing toxic algae control strategies. Prymnesium parvum was passed through columns of the filter medium. Algal cell counts and visual observations were used to assess mortality; fish bioassays were conducted to assess toxicity. Smart Sponge Plus successfully killed the algae, although toxins were released during filtration. After filtration, 87-100% algal removal was achieved, with the variability potentially being related to cell density at the initiation of the test. Smart Sponge was also successful in reducing associated the toxicity of P. parvum, as was a charcoal medium. Smart Sponge Plus shows promise for use in the management of golden algal blooms by reducing cell density and should be further evaluated in hatchery and field settings.
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