Abstract
In artificial pools Gambusia affinis greatly reduced rotifer, crustacean, and insect populations and thus permitted extraordinary development of phytoplankton populations (2x108 cells per milliliter). Other effects included decreased optical transmissivity and increased temperature of the water, decreased amounts of dissolved inorganic phosphorus, and increased amounts of dissolved organic phosphorus, inhibition of Spirogyra, and replacement of one annelid, Chaetogaster, by another, Aeolosoma.
