This study completes a segment of a project to evaluate the use of anhydrous ammonia as a fisheries management technique in small impoundments. Objectives were to determine the feasibility of using anhydrous ammonia for fish eradication, for pond fertilization, and for vegetation control. Treatments in 15 pounds in Central Texas indicate that anhydrous ammonia fulfills these objectives. Anhydrous ammonia was selected because of known toxicity to fishes and because ammonia is a naturally occurring compound. Thus, the use of anhydrous ammonia as a total or selective population control agent will not leave a persistent nondegradable residue in a pond. Treatment rates varied from 13 to 40 ppm of anhydrous ammonia. Higher treatment rates caused total kills while lower treatment rates appeared selective for certain species. Phytoplankton and zooplankton populations were decimated and recovered slowly. As expected, profound changes in ammonia, pH, C02, and alkalinity occurred following treatments.
