Growth Rates and Digestive Abilities of Bullfrog Tadpoles (Rana catesbeiana) Fed Algal Diets

Abstract

Although there are many accounts of the diversity of algae consumed by anuran larvae, growth and digestive responses of tadpoles fed algae have been poorly studied. In this study, growth rates and digestive abilities of larval bullfrogs (Rana catesbeiana) fed monospecific algal diets were investigated. The four algal species used in feeding trials were Selenastrum capricornutum, Microcystis incerta, Anabaena flos-aquae, and Ulothrix coniferricola. The filamentous blue-green alga Anabaena flos-aquae was the only alga that promoted growth in tadpoles and was digested more thoroughly than the other algae. Ability of tadpoles to digest nuisance, bloom-forming algae such as Anabaena has important implications in freshwater resource management. Such results also contribute to a better understanding of the roles tadpoles play in nutrient cycling, their potential to combat eutrophication, and their influence on primary productivity in freshwater ecosystems.